37 Green Chemistry綠色化學 7D 7E 37.1 Concepts of Green Chemistry 綠色化學的概念 37.2 Some Green Chemistry Practices 綠色化學的實踐

Concepts of Green Chemistry綠色化學的 概念 37.1 Concepts of Green Chemistry綠色化學的 概念 http://www.epa.gov/greenchemistry/

37.1 Concepts of Green Chemistry (SB p.207) Introduction簡介 Chemical industry has been very important in manufacturing 化學工業對製造下列物品非常重要：  drugs for our health藥物  fertilizers and pesticides肥料和殺蟲劑  various important products其他重要的化學品 (e.g. polymers聚合物, dyes染料, cosmetics化妝品) Our living qualities have been improved 化學工業使我們的生活質素日漸提高

37.1 Concepts of Green Chemistry (SB p.207) Introduction簡介 The manufacture of these chemical products improve our living qualities這些產品的製造與化學息息相關，大大改善了我們的生活質素

37.1 Concepts of Green Chemistry (SB p.207) Sustainable Development and Green Chemistry 可持續發展和綠色化學 First came out of the United Nations Commission on Environment and Development in 1987 (Brundtland Commission)最初由聯合國環境與發展委員會（布倫特蘭委員會）在 1987 年提出 Defined sustainable development as: 它把可持續發展定義為 “...... Meeting the needs of the present without compromising the ability of future generations to meet their own needs.” 「……我們在消耗地球資源來滿足自身需要的同時，不應影響後世滿足他們需要的能力。」

Sustainable Development and Green Chemistry可持續發展和綠色化學 37.1 Concepts of Green Chemistry (SB p.208) Sustainable Development and Green Chemistry可持續發展和綠色化學 The Earth has a limited natural capacity  for diluting and assimilating the waste and pollutants that the human society generates 地球稀釋和吸收人類社會所產生的廢物和污染物的能力有限

Sustainable Development and Green Chemistry可持續發展和綠色化學 37.1 Concepts of Green Chemistry (SB p.208) Sustainable Development and Green Chemistry可持續發展和綠色化學 With rapidly rising population and industrialization in recent decades, 近數十年，隨著人口的增加和工業化的普及  that capacity is exceeded　 地球稀釋和吸收廢物和污染物的能力已到了極限  our lifestyle is not sustainable 我們的生活方式已不是可持續的

Sustainable Development and Green Chemistry可持續發展和綠色化學 37.1 Concepts of Green Chemistry (SB p.207) Sustainable Development and Green Chemistry可持續發展和綠色化學 Promotion of sustainable development in Hong Kong 香港政府積極提倡可持續發展

Sustainable Development and Green Chemistry可持續發展和綠色化學 37.1 Concepts of Green Chemistry (SB p.208) Sustainable Development and Green Chemistry可持續發展和綠色化學 The disposal problem of computer waste is one of the concerns of sustainable development 電腦廢物的棄置問題是可持續發展其中一個關注的議題

37.1 Concepts of Green Chemistry (SB p.208) During the early 1990s,在 1990 年代初  the US Environmental Protection Agency (EPA) coined the phrase “green chemistry” 美國環境保護局（EPA）創作「綠色化學」片語  promote innovative chemical technologies 藉著發展新的化工技術  reduce or eliminate the use or generation of hazardous substances in the design,　 manufacture and use of chemical products 在設計、製造和使用化合物時，確保整個生產 過程對環境造成的負面影響最低

Sustainable Development and Green Chemistry可持續發展和綠色化學 37.1 Concepts of Green Chemistry (SB p.208) Sustainable Development and Green Chemistry可持續發展和綠色化學 Green chemistry is the use of chemistry for prevention of pollution problems 綠色化學是利用化學方法來防止環境污染  involves the design of chemical products and processes that are environmentally benign 它涉及設計化學品及其生產過程， 生產過程需要符合環境保護的要求

Sustainable Development and Green Chemistry可持續發展和綠色化學 37.1 Concepts of Green Chemistry (SB p.208) Sustainable Development and Green Chemistry可持續發展和綠色化學 Green chemistry covers all aspects and types of chemical processes  reduce negative impacts to human health and the environment 綠色化學涵蓋所有減少對人類及環境 帶來負面影響的方法

Sustainable Development and Green Chemistry可持續發展和綠色化學 37.1 Concepts of Green Chemistry (SB p.208) Sustainable Development and Green Chemistry可持續發展和綠色化學 Green chemistry is environmentally benign綠色化學有利於環境  links the design of chemical products and processes with their impacts on human health and the environment 能把設計和製造化學品的過程及它們對 人類健康和環境的影響聯繫起來 Example 37-1 Activity活動

活動 : Group activity (p.208) Discuss the feasibility of using the principles of green chemistry for daily life application of chemistry. 討論日常生活中運用綠色化學的原則的可行性。 Green chemistry involves the design of chemical products and processes that are environmentally benign. Green chemistry covers all aspects and types of chemical processes that reduce negative impacts to human health and the environment. 綠色化學涉及設計化學品及其生產過程, 而生產過程需要符合環境保護的要求。綠色化學涵蓋所有減少對人類及環境帶來負面影響的方法。 In this activity, form a group of four or five students and then discuss the feasibility of using the principles of green chemistry for daily life applications of chemistry.這個活動中，每四或五個同學組，討論在日常生活應用中運用綠色化學的原則的可行性。

Example 37-1 (2) (3) 37.1 Concepts of Green Chemistry (SB p.208) In what ways can green chemistry contribute to achieving sustainability?綠色化學怎樣有效達致可持續發展的目標？ Green chemistry can contribute to achieving sustainability in three key areas: 綠色化學從以下三方面達致可持 續發展的目標： It is used to harness renewable energy technologies like utilization of solar energy, making of fuel cells and so on. 利用可再生能源，例如太陽能和燃料電池 (1) Green chemists can help the switching of the reagents used mostly derived from petroleum to renewable sources so as to reduce our dependence on fossil fuels. 利用可再生資源作為原料，以取代化石燃料，從而減少我們對化石燃料的需求 (2) (3) Green chemistry works on the replacement of polluting technologies by environmentally benign alternatives. Hence, it can reduce pollution and waste production. 利用環保技術，以取代對環境有害的技術，從而減少污染或廢物的產生

Green Chemistry andsustainable development 綠色化學和可持續發展 Green Chemistry is chemistry for the environment. It was first defined by the US Environmental Protection Agency(EPA) as “the utilization of a set of principles that reduces or eliminates the use or generation of hazardous substances in the design, manufacture and application of chemical products”. 綠色化學係一門學問，諗下點樣用化學整嘢出來之時，佢個過程同產品都到最少污染物，從而可以保護環境。 Education for sustainable development is about the learning needed to maintain and improve our quality of life and the quality of life for future generations. 可持續發展教育我們學習維持改善生活的質素和下一代的生活質素。

12 principles of Green Chemistry Prevention – it is better to prevent waste than to treat or clean up waste預防有廢物 Atom economy – synthetic methods should be designed to maximize the incorporation of all materials used into the final product. 用盡反應物所有原子。 Less hazardous chemical synthesis 降低化學合成方法的危險: 降低或消除生成產物的合成方法對人類及環境的毒性。

12 principles of Green Chemistry 筆記notes 12 principles of Green Chemistry Design safer chemicals設計低毒性化學品。 Safer solvents and auxiliaries 少用或者用安全溶劑同輔助物。 Design for energy efficiency 為慳能源、少影響環境，反應條件以常溫常壓狀態為主。 Use renewable feedstocks使用永續資源為原料。 Reduce derivatives簡化反應步驟，減少整出非必要性衍生物。

12 principles of Green Chemistry 筆記notes 12 principles of Green Chemistry Catalysis 盡可能使用高選擇性嘅催化劑。 Design chemicals and products to degrade after use 設計可分解嘅化學品 Real-time analysis for pollution prevention 及時偵測污染物。 Minimize the potential for accidents 慎選過程用嘅化學物質，以減少意外災害發生。

Work of chemists 化學家的工作 Devise greener reaction conditions for old syntheses.設計較綠色的反應條件。(Room Temp, 1 atm) Develop greener synthesis for existing chemicals. 發展現存化合物的較綠色合成方法。 Design new compounds that are less toxic but have the same desirable properties as an existing compound. 設計毒性較低的新化合物取代現存化合物。 1 e.g. replace an organic solvent with water or eliminate solvent altogether. 2 e.g. use biomass instead of petrochemical feedstock 2 e.g. use catalysts rather than stoichiometric reagents 3 e.g. a new pesticide that is toxic only to target organisms and biodegrades to harmless substances.

Preparing propene(丙烯) – reaction(反應) 1 Atom economy原子經濟性 筆記notes Preparing propene(丙烯) – reaction(反應) 1 15 17 14 43 C3H6=42 x 100% Formula mass of desired product Formula mass of all products = % atom economy 原子經濟性百分比 C4H13N +OH- C3H6 + ….. = 35% % atom economy of reaction 1 =

Preparing propene – reaction 2 筆記notes Atom economy原子經濟性 Preparing propene – reaction 2 C3H6=42 60 C3H7OH C3H6 + H2O x 100% Formula mass of desired product Formula mass of all products = % atom economy 原子經濟性百分比 % atom economy of reaction 2 = = 70%

Traditional synthesisof Ibuprofen 布洛芬傳統合成法 筆記notes Traditional synthesisof Ibuprofen 布洛芬傳統合成法 2008al-chemistry PII#6(c) 6 main steps

6 main steps 40% only

Alternative synthesis of Ibuprofen布洛芬另一合成法 3 main steps 77%

Some Green Chemistry Practices 綠色化學的實踐 37.2 Some Green Chemistry Practices 綠色化學的實踐 Decaffeination using Supercritical Carbon Dioxide 使用超臨界二氧化碳移除咖啡因 A B Use of Hydrogen Peroxide as a Bleaching Agent 使用添加了錳基催化劑的過氧化氫作為漂白劑

What is supercritical carbon dioxide甚麼是超臨界二氧化碳? A supercritical fluid is a substance above its critical temperature and critical pressure. Under these conditions the distinction between gases and liquids does not apply and the substance can only be described as a fluid. 超臨界流體是位於臨界溫度和壓強之上。於此狀態下液態和氣態已無法明顯區別, 只能稱為流體。 s6-part04-past Paper_Chi_eng-p.2 2008PII#1(a)(i) –SCF CO2

Supercritical fluid of CO2 超臨界流體的CO2 Above 31.1 0C and 73 atm carbon dioxide behaves as a supercritical fluid and shows properties of both a liquid and a gas. It fills the container, like a gas, and dissolves substances like a liquid. 此時形成超臨界流體,同時具有液氣性質。 如氣體般可填充整個容器和如液體溶解其他物質。

Supercritical fluid of CO2 超臨界流體的CO2 液態 liquid 氣態gas With an increase in temperature the meniscus begins to diminish. 溫度升高, 兩相間的彎月面,新月面開始消失。 The liquid density falls due to expansion and the gas density rises as more of the substance evaporates. 液態密度因體積澎張而下降,氣態密度因蒸發而增加。

Supercritical fluid of CO2 超臨界流體的CO2 Once the critical temperature and pressure have been reached the two distinct phases of liquid and gas are no longer visible. The meniscus can no longer be seen. One homogenous phase called the “supercritical fluid” phase occurs. 當達致臨界溫度和壓強時, 兩個不同相再無法分辨,而界面的新月面亦消失生成一同相的超臨界流體。 超臨界流體 supercritical fluid

s6-part04-past Paper_Chi_eng-p.2 -2008PII#1(a) –SCF CO2 1. (a) (i) 根據以下資訊, 描繪二氧化碳的壓強-溫度標示圖。圖中須指超臨界流體的區域。 triple point三相點: -56°C and 5.1 atm critical point臨界點: 31°C and 72.9 atm 固態二氧化碳的密度高於液態二氧化碳。 (ii) 說明超臨界流體的一項特性。 (iii) 超臨界二氧化碳可應用於多方面。例如作為乾洗溶劑和除咖啡因溶劑。說明使用有機溶劑於此等用途和對比使用超臨界二氧化碳的二項優點。 (iv) 有一學生作出以下結論: 「因為二氧化碳是一種溫室氣體, 工業上若廣泛使用超臨界二氧化碳會對環境產生損害。」 你是否認同此學生?試解釋。 (7 marks) Powerpoint –Ch.11 Ch11-intermolecular-Eng-中文.ppt

s6-part04-past Paper_Chi_eng-p.2 -2008PII#1(a) –SCF CO2 1. (a) (i) Based on the information given below, sketch a labelled pressure-temperature diagram for carbon dioxide. Indicate on your diagram the supercritical fluid region. triple point: -56°C and 5.1 atm critical point: 31°C and 72.9 atm solid carbon dioxide is denser than liquid carbon dioxide (ii) State ONE characteristic of a supercritical fluid. (iii)Supercritical carbon dioxide finds a number of applications, e.g. as a dry-cleaning solvent and as a decaffeinating solvent. State TWO advantages of using supercritical carbon dioxide over using organic solvents in such applications. (iv) A student made the following assertion: 'As carbon dioxide is a greenhouse gas, the extensive use of supercritical carbon dioxide in industry will pose harm to our environment.' Do you agree with the student? Explain. 。 (7 marks) Powerpoint –Ch.11 Ch11-intermolecular-Eng-中文.ppt

2008PII#1(a)(i)-Page 2-part 04 3 marks 根據以下資訊, 描繪二氧化碳的壓強-溫度標示圖。圖中須指超臨界流體的區域。Based on the information given below, sketch a labelled pressure-temperature diagram for carbon dioxide. Indicate on your diagram the supercritical fluid region. triple point三相點: -56°C and 5.1 atm critical point臨界點:31°C and 72.9 atm Solid carbon dioxide is denser than liquid carbon dioxide. 固態二氧化碳的密度高於液態二氧化碳。 Slope斜率 = +ve (s) > (l) e.g.CO2 超臨界流體 supercritical fluid 加入p.281 Pressure（atm) 壓強 72.9 p.288 Slope斜率 = -ve (s) < (l) e.g. H2O 5.1 Slope斜率 =  (s) = (l) e.g. He Temp溫度 OC -56 31

它像氣體般填充整個容器, 但密度則與液體相若。 s6-part04-past Paper_Chi_eng-p.2 -2008PII#1(a) –SCF CO2 supercritical fluid 超臨界流體 1 marks 它像氣體般填充整個容器, 但密度則與液體相若。 It fills its container like a gas but with a density like that of a liquid.

s6-part04-past Paper_Chi_eng-p.2 -2008PII#1(a) –SCF CO2 (iii) Supercritical carbon dioxide finds a number of applications, e.g. as a dry-cleaning solvent and as a decaffeinating solvent. State TWO advantages of using supercritical carbon dioxide over using organic solvents in such applications. 超臨界二氧化碳可應用於多方面。例如作為乾洗溶劑和除咖啡因溶劑。說明使用有機溶劑於此等用途和對比使用超臨界二氧化碳的二項優點。 以下任何兩項 Any TWO of the following: 2 - 它不會引致漏出有毒/致癌/污築空氣的有機帶劑。 It will not lead to leakage of organic solvents, which may be toxic/carcinogenic/ air pollutants. - 二氧化碳無毒/不易燃。 Carbon dioxide is non-toxic/non-flammable. - 使用超臨界CO2的過程可在室溫下操作，可減低能源的成本。 The processes involving the use of supercritical CO2 are operated at room temperature. The energy cost can be reduced.

2008PII#1(a)(iv)-Page 2-part 04 1 marks (iv) A student made the following assertion: 有一學生作出以下結論: 'As carbon dioxide is a greenhouse gas, the extensive use of supercritical carbon dioxide in industry will pose harm to our environment.' 「因為二氧化碳是一種溫室氣體, 工業上若廣泛使用超臨界二氧化碳會對環境產生損害。」 Do you agree with the student? Explain. 你是否認同此學生?試解釋。 No. In the process no new CO2 is generated. 否。在過程中，不另產生CO2。 1 part 04-Page 8- 2003PI#2(a)(i)(ii)-CO2

Decaffeination using Supercritical Carbon Dioxide使用超臨界二氧化碳移除咖啡因 37.2 Some Green Chemistry Practices (SB p.209) A Decaffeination using Supercritical Carbon Dioxide使用超臨界二氧化碳移除咖啡因 1. Caffeine咖啡因 Occurs naturally in tea, coffee, cocoa and chocolate products茶、咖啡、可可豆和巧克力等食品都含有天然咖啡因 Added to soft drinks and a variety of both prescription and over-the-counter drugs 人們亦把咖啡因加入汽水，以及各種各樣的處方和非處方(市售)藥物中

1. Caffeine咖啡因 Major action:咖啡因的主要作用 37.2 Some Green Chemistry Practices (SB p.209) 1. Caffeine咖啡因 Major action:咖啡因的主要作用  stimulate the central nervous system 刺激人體的中樞神經  make people less sleepy 減少睡意 Also a mild painkiller that can relieve pains它一種溫和的止痛劑，可以減輕痛楚

1. Caffeine咖啡因 Tea, coffee andcocoa contain caffeine 茶、咖啡因和可可豆都含有天然咖啡因 37.2 Some Green Chemistry Practices (SB p.209) 1. Caffeine咖啡因 Tea, coffee andcocoa contain caffeine 茶、咖啡因和可可豆都含有天然咖啡因 Caffeine is added to soft drinks and some drugs人們把咖啡因加入汽水和某些藥物中

红牛维生素功能饮料 （Red Bull Energy Drink) 牛磺酸（taurine）：1100毫克 葡萄糖醛酸内酯（glucuronolactone）：600毫克 咖啡因（caffeine）：80毫克， 其成份粹取自咖啡豆浓缩物 烟碱酸（niacin，又称为维生素B3）：20毫克 维生素B6（vitamin B6）：5毫克 泛酸（pantothenic acid， 又称为维生素B5）：5毫克 维生素B12（vitamin B12）：0.005毫克 果糖（sucrose）：21.5克 葡萄糖（glucose）：5.25克

英女喝4 罐紅牛致死 壹蘋果生活網 - 2009年2月3日 英國21 歲女大學生莉奇（ 左圖） ， 去年9 月在夜店暴斃， 死因聆訊指， 死者當時飲了四罐紅牛（ 右圖） 和兩杯含有伏特加的飲品後， 因攝取過多咖啡因， 令心跳加速， 而她患有罕見隱性心臟病， 最後心臟不勝負荷而倒斃。 本網站內容只供參考，無意取代專業醫療諮詢。

2010-01-29 記者：蔡元貴、倪清江 【本報訊】一名去年中學會考取得 8A1B的數學奇才，前日在課堂中暈倒，送院時仍能清醒對答，卻在送院後不久猝死。這位中六尖子一星期前開始患上氣管炎，有醫生說，他可能是受過濾病毒感染，導致心肌炎。校方昨日舉行追思會，有師生在課室內泣不成聲。 死者陳俊淇，就讀香港道教聯合會鄧顯紀念中學的中六理科班。前日下午，俊淇在化學課堂中突然暈倒，懂得急救的老師即時替他量度脈搏，當時俊淇臉色蒼白，但仍有呼吸，而且對老師的問題仍能清晰對答。校方召喚救護車，並通知俊淇家長。 送院時，俊淇病情似乎並不嚴重，其母親趕到醫院時，俊淇仍保持清醒，能與母親對答。但再過了一段時間，俊淇就陷入昏迷，搶救無效，至晚上 7時證實不治。

隱性心臟病難察覺 俊淇猝死前患上氣管炎，暫時未知是否與死因有關，有待化驗報告交代。呼吸系統專科醫生梁宗存說，氣管炎可能是感染過濾病毒的徵兆，若病人患有隱性心臟病，則有可能受病毒感染而引發心肌炎。嚴重的心肌炎可導致心臟無法提供正常的血液循環，病人會感覺暈眩，繼而心律不正，最終死亡。 心臟科專科醫生鄭俊豪說，隱性心臟病如先天性心律不正，很難靠身體檢查察覺。理論上，病人可以利用電生理檢查，利用導管測試心臟不同部位的心跳，檢視病人是否患有心臟病，但通常只有在家族患有心臟病的情況下，醫生才會建議病人接受電生理檢查。 另一種猝死可能是哮喘發作，梁宗存說，冬天的低溫與混濁空氣是誘發哮喘的高危季節。本港平均每年有 80人至 90人因哮喘病發而死，其中三成是 35歲以下患者。 

37.2 Some Green Chemistry Practices (SB p.210) 1. Caffeine咖啡因 不是啡色 The IUPAC name of caffeine is 1,3,7-trimethylxanthine 咖啡因的系統名稱是 1,3,7-三甲基黃嘌呤(2 環) Molecular formula分子式: C8H10N4O2 分子式是 C8H10N4O2 Caffeine is white in colour and has a bitter taste 咖啡因呈白色，並帶有苦味

1. Caffeine咖啡因 Structural formula of caffeine 咖啡因的結構式 37.2 Some Green Chemistry Practices (SB p.210) 1. Caffeine咖啡因 Structural formula of caffeine 咖啡因的結構式 Ball-and-stick model of caffeine 咖啡因的球棒模型 戴立體眼鏡 可見立體

2. Decaffeinated Coffee移除咖啡因的咖啡 37.2 Some Green Chemistry Practices (SB p.210) 2. Decaffeinated Coffee移除咖啡因的咖啡 Coffee naturally contains caffeine 咖啡含有天然咖啡因 Some people like caffeine for its stimulating effect as well as its characteristic taste 很多人為了提神，又或者因為咖啡的特別味道而飲用咖啡

2. Decaffeinated Coffee移除咖啡因的咖啡 37.2 Some Green Chemistry Practices (SB p.210) 2. Decaffeinated Coffee移除咖啡因的咖啡 There are people who do not want caffeine for health or other reasons 但有些人則不能接受咖啡因，  can opt for decaffeinated coffee 為了迎合這些人的需要，市場上提供 移除咖啡因的咖啡  coffee without caffeine (or more accurately with very low caffeine level) 較準確來說，這些移除咖啡因的咖啡 所含的咖啡因水平非常低

2. Decaffeinated Coffee移除咖啡因的咖啡 37.2 Some Green Chemistry Practices (SB p.210) 2. Decaffeinated Coffee移除咖啡因的咖啡 Decaffeinated coffee移除咖啡因的咖啡

3. Decaffeination移除咖啡因的過程 37.2 (SB p.210) The first decaffeinated coffee was made by首次移除咖啡  extracting the caffeine from green coffee beans with trichloromethane 從綠色的咖啡豆中提取出咖啡因時，使用三氯甲烷俗稱哥羅芳CHCl3） Since then various organic solvents (e.g. benzene and trichloroethane) were used 自此以後，人們使用不同的有機溶劑（例如苯和三氯乙烯）移除咖啡中的咖啡因 all toxic 它們都是有毒 caused environmental and health concerns 對環境和人類的健康造成不良的影響

Later evidence suggested that 後來有研究指出 37.2 Some Green Chemistry Practices (SB p.210) In early 1970s 1970 年代早期,  dichloromethane, CH2Cl2, became the solvent of choice 二氯甲烷（CH2Cl2）成為主要使用的溶劑  1. its lower toxicity它的毒性較低 2. its ability to selectively dissolve caffeine without carrying off sugars, peptides, and flavor ingredients 它只會溶解咖啡中的咖啡因， 而不會同時移除咖啡中的糖分和天然香料 Later evidence suggested that 後來有研究指出  dichloromethane might be carcinogenic 二氯甲烷可能會致癌  its use was sharply reduced 它的使用亦自此大大減少

3. Decaffeination移除咖啡因的過程 37.2 Some Green Chemistry Practices (SB p.211) 3. Decaffeination移除咖啡因的過程 Currently, three main methods used for decaffeination of coffee are 現時，三種移除咖啡因的方法包括:  water decaffeination 利用水移除咖啡因  carbon dioxide decaffeination 利用二氧化碳移除咖啡因  solvent decaffeination　 利用溶劑移除咖啡因

3. Decaffeination移除咖啡因的過程 37.2 Some Green Chemistry Practices (SB p.211) 3. Decaffeination移除咖啡因的過程 Water decaffeination and carbon dioxide decaffeination利用水移除咖啡因和利用二氧化碳移除咖啡因  commonly used by major manufacturers 生產商常用的方法 Solvent decaffeination利用溶劑移除咖啡因  governed by legislation 受到國際法例和很少採用這個方法歐洲法 例的管制

3. Decaffeination移除咖啡因的過程 37.2 Some Green Chemistry Practices (SB p.211) 3. Decaffeination移除咖啡因的過程 In solvent decaffeination 常用來移除咖啡因的溶劑  the solvent commonly used is dichloromethane二氯甲烷(CH2Cl2)  may cause both environmental and health concerns 它可能對環境和健康帶來負面的影響

Decaffeination using supercritical carbon dioxide 使用超臨界二氧化碳移除咖啡因的過程 37.2 (SB p.211) Phase diagram of carbon dioxide二氧化碳的相圖 CO2 behaves as a supercritical fluid above its critical temperature (31°C) and pressure (73 atm) 在超過CO2的臨界溫度（31 oC）和壓強（73 atm）的情況下，二氧化碳以超臨界液體的狀態存在

Decaffeination using supercritical carbon dioxide 使用超臨界二氧化碳移除咖啡因的過程 37.2 Some Green Chemistry Practices (SB p.211) Decaffeination using supercritical carbon dioxide 使用超臨界二氧化碳移除咖啡因的過程 Supercritical carbon dioxide is a nearly ideal solvent 超臨界二氧化碳幾乎是一種理想的溶劑 Under normal conditions, carbon dioxide is not a very good solvent for organicsubstances 在常溫常壓下，二氧化碳並不是有機化合物的良好溶劑 Supercritical carbon dioxide readily dissolves many of these substances, including caffeine 很多物質（包括咖啡因）都很易溶於超臨界二氧化碳

Decaffeination using supercritical carbon dioxide 使用超臨界二氧化碳移除咖啡因的過程 37.2 Some Green Chemistry Practices (SB p.211) Decaffeination using supercritical carbon dioxide 使用超臨界二氧化碳移除咖啡因的過程 The use of supercritical carbon dioxide to replace dichloromethane in extracting caffeine from coffee beans is a green chemistry practice 使用超臨界二氧化碳從咖啡豆移除咖啡因是綠色化學的實踐的其中一個例子 Compared to dichloromethane與二氯甲烷相比,  carbon dioxide is non-toxic and does not cause environmental problems 二氧化碳既無毒，又不會引致環境問題

Decaffeination using supercritical carbon dioxide 使用超臨界二氧化碳移除咖啡因的過程 37.2 Some Green Chemistry Practices (SB p.211) Decaffeination using supercritical carbon dioxide 使用超臨界二氧化碳移除咖啡因的過程 Traditionally, caffeine was removed with a solvent called methylene chloride (CH2Cl2, a suspected carcinogen). Unfortunately, many of the other compounds in coffee (those responsible for its flavor and smell) were also soluble in methylene chloride. 傳統上，二氯甲烷(一可疑致癌物質)移除咖啡因。不幸的是，在咖啡中許多其他化合物（那些負責其味道和氣味）也溶於二氯甲烷。 Many governments tighten regulationson environmentally hazardous solvents (such as methylene chloride). 許多國家的政府加強管制對環境有害的溶劑（如亞甲基氯化物）。

Decaffeination using supercritical carbon dioxide 使用超臨界二氧化碳移除咖啡因的過程 37.2 Some Green Chemistry Practices (SB p.211) Decaffeination using supercritical carbon dioxide 使用超臨界二氧化碳移除咖啡因的過程 補充 Supercritical carbon dioxide gains its popularity due to it‘s relatively mild critical points of 31.1 0C and 73 atm.  It is also abundant and mostly benign. 超臨界二氧化碳中獲得其受歡迎因為它的相對溫和的臨界點31.1 0℃和73個大氣壓。也是豐富及溫和。 Supercritical solvent (carbon dioxide) can easily remove most of the caffeine from the raw coffee beans, but aromatic compounds responsible for taste and smell are largely left in the beans. 只溶解咖啡因,大部份相關味道和氣味之物質郤餘下。 Supercritical carbon dioxide method is said to be the best of the chemical decaffeination processes currently in use. This method uses carbon dioxide, which is more stable than the other chemicals employed for caffeine extraction. Residual carbon dioxide can be safely vented into the atmosphere without any harmful effects on the environment. In addition, precise control over temperature and pressure can selectively remove caffeine leaving most, if not all, of the flavour intact. Removing 97-99% of a coffee's caffeine is possible employing this method. In addition, this method leaves behind little or no toxic residue and is therefore not usually a health concern. The disadvantages of using this method include the fact that it's rather costly, since the high pressure used requires expensive equipment.

Decaffeination process移除咖啡因的過程 37.2 Some Green Chemistry Practices (SB p.211) 補充 Decaffeination process移除咖啡因的過程 萃取器 水 SOAKING(浸) green coffee beans in water doubles their size, allowing the caffeine to dissolve into water inside the bean. ” 用水浸綠色咖啡豆發脹, 容許水溶解豆中的咖啡因。 CAFFEINE REMOVAL 移除咖啡因 occurs in an extraction vessel. Caffeine diffuses into this supercritical carbon dioxide, along with some water. 於萃取器咖啡因擴散至超臨界二氧化碳中。　 浸豆 CO2 Beans enter at the top of the chamber and move toward the bottom over five hours. To extract the caffeine continuously, the beans lower in the column are exposed to fresher carbon dioxide, which ensures that the caffeine concentration inside beans is always higher than in the surrounding solvent. Caffeine therefore always diffuses out of the beans.  已處理 的豆 水+CO2 吸收室

37.2 Some Green Chemistry Practices (SB p.211) 補充 水 萃取器 浸豆 CO2 DECAFFEINATED BEANS at the bottom of the vessel are removed, dried and roasted.  從底部收集無咖啡因的咖啡豆 烘乾。 RECOVERY of dissolved caffeine occurs in an absorption chamber. A shower of water droplets leaches the caffeine out of the supercritical carbon dioxide. 吸收塔中, 利用花灑的水滴將超臨界二氧化碳中的咖啡因吸濾取。 The caffeine in this aqueous extract is then often sold to soft-drink manufacturers and drug companies. The purified carbon dioxide is recirculated for further use.  已處理 的豆 水+CO2 吸收室

#4工業利用超臨界CO2萃取 Industrial extraction with supercritical CO2 37.2 Some Green Chemistry Practices (SB p.215)#4 補充 #4工業利用超臨界CO2萃取 Industrial extraction with supercritical CO2 Decaffeinating coffee and tea 移除荼和咖啡的咖啡因 Extracting bitterness from hops to make beer 萃取啤酒花 的苦味後, 製煉啤酒 Defatting cocoa powder 可可粉脫脂。 Extracting spices and aromatic plants 從芳香植 物萃取香料

Significant properties of supercritical fluids #5超臨界流體的特殊性質 37.2 Some Green Chemistry Practices (SB p.215)#5 補充 Significant properties of supercritical fluids #5超臨界流體的特殊性質 Diffusivity 擴散性 gas > supercritical fluid > liquid 氣體 > 超臨界流體 > 液體 Viscosity 黏性 (度) gas < supercritical fluid < liquid 氣體 < 超臨界流體 < 液體 Surface表面 tension,張力 gas = supercritical fluid < liquid 氣體 = 超臨界流體 < 液體 Density 密度 gas < supercritical fluid < or = liquid氣體 < 超臨界流體 <或= 液體

#6 Benefits of using supercritical CO2 for extraction 用超臨界CO2萃取的好處 37.2 Some Green Chemistry Practices (SB p.215)#6 補充 #6 Benefits of using supercritical CO2 for extraction 用超臨界CO2萃取的好處 It is has the penetration power of a gas and the extraction power of a liquid. 具備氣體的穿透力和液體的萃取能力。 It acts as a solvent to extract organic compounds with a low molecular weight. 萃取低分子量有機化合物的溶劑。 It leaves no residual trace on treated material 處理物質後没有殘餘痕跡。 It respects the environment.不污染(尊重)環境。 Low viscosity and surface tension results in small pore penetration. High diffusivity helps to increase rate of reaction.

Supercritical CO2 as solvent 用超臨界CO2作溶劑 37.2 Some Green Chemistry Practices (SB p.215)#7 補充 Supercritical CO2 as solvent 用超臨界CO2作溶劑 #7 Purification of specialty chemicals and useful natural products 淨化指定化合物和有用的天然生成物。 An alternative solvent in coatings industry (replacing 40 - 90% of volatile solvents). 塗層工業的替代溶劑(替代40 - 90% 的揮發性溶劑)。 Degreasing and dry cleaning applications 除脂和乾洗應用。 Increasingly applied as a solvents in synthetic industrial processes 工業合成過程的溶劑。

37.2 Some Green Chemistry Practices (SB p.212) Use of Hydrogen Peroxide as a Bleaching Agent 使用添加了錳基催化劑的過氧化氫作為漂白劑 B Bleaching agents are used to remove colours from materials 漂白劑是用來去除物料的顏色 Very important in both textile industry and household cleaning 它在製衣業和家居清潔方面都十分重要

37.2 Some Green Chemistry Practices (SB p.212) Use of Hydrogen Peroxide as a Bleaching Agent 使用添加了錳基催化劑的過氧化氫作為漂白劑 B The most common household bleaching agent is chlorine bleach 最常見的家居漂白劑是氯漂白劑  contains hypochlorite (ClO－) as the active ingredient 它含有次氯酸根離子(ClO－)作為有效成分

Chlorine bleach has several disadvantage 氯漂白劑有幾個缺點: 37.2 Some Green Chemistry Practices (SB p.212) Use of Hydrogen Peroxide as a Bleaching Agent 使用添加了錳基催化劑的過氧化氫作為漂白劑 B Chlorine bleach has several disadvantage 氯漂白劑有幾個缺點: chlorine gas may evolve during the bleaching process 部分氯氣會在漂白過程中逸出 poisonous chlorinated organic compounds may be formed during the bleaching process 漂白過程中，可能生成含氯的有機化合物, 這些化合物通常都有毒的  causing environmental problems 會引致環境問題

Available in various concentrations 它分為幾種不同的濃度 37.2 Some Green Chemistry Practices (SB p.212) Use of Hydrogen Peroxide as a Bleaching Agent 使用添加了錳基催化劑的過氧化氫作為漂白劑 B Hydrogen peroxide (H2O2) is a viscous liquid that has strong oxidizing power 過氧化氫（H2O2）是一種帶黏性的液體，氧化能力極高 Available in various concentrations 它分為幾種不同的濃度  including包括6%, 30% and 50%

37.2 Some Green Chemistry Practices (SB p.212) Use of Hydrogen Peroxide as a Bleaching Agent 使用添加了錳基催化劑的過氧化氫作為漂白劑 B Aqueous solutions of 3% hydrogen peroxide are often used as a bleach and as a topical antiseptic 濃度為 3% 的過氧化氫水溶液通常被用作漂白劑和局部抗菌劑 Commercial hair bleaches also contain hydrogen peroxide at 6% concentration 商業用的染髮劑一般含有濃度為 6% 的過氧化氫

Hydrogen peroxide bleaches by oxidation 過氧化氫通過氧化作用進行漂白 37.2 Some Green Chemistry Practices (SB p.212) Use of Hydrogen Peroxide as a Bleaching Agent 使用添加了錳基催化劑的過氧化氫作為漂白劑 B Hydrogen peroxide bleaches by oxidation 過氧化氫通過氧化作用進行漂白

The process is environmentally friendly 水並不會造成環境污染 37.2 Some Green Chemistry Practices (SB p.212) Use of Hydrogen Peroxide as a Bleaching Agent 使用添加了錳基催化劑的過氧化氫作為漂白劑 B Hydrogen peroxide is reduced to water which is non-polluting 漂白過程中，過氧化氫被還原為水 The process is environmentally friendly 水並不會造成環境污染 Hydrogen peroxide acts as a green bleaching agent 過氧化氫是一種環保的漂白劑

The use of a catalyst (e.g. manganese(IV) oxide) 使用催化劑（例如氧化錳(IV)） 37.2 Some Green Chemistry Practices (SB p.212) Use of Hydrogen Peroxide as a Bleaching Agent 使用添加了錳基催化劑的過氧化氫作為漂白劑 B The use of a catalyst (e.g. manganese(IV) oxide) 使用催化劑（例如氧化錳(IV)）  greatly increases the rate of bleaching action of hydrogen peroxide 能大大加快過氧化氫的漂白速度

Use of H2O2 as a Green Bleaching Agent in Industry 工業上使用過氧化氫作為環保漂白劑 37.2 Some Green Chemistry Practices (SB p.212) Use of H2O2 as a Green Bleaching Agent in Industry 工業上使用過氧化氫作為環保漂白劑 In paper manufacturing在紙的製造過程中,  chlorine is commonly used to remove wood pulp from lignin 一般會使用氯從木質紙漿中去除木質素 However, the use of chlorine gives rise to environmental problems這會引致環境問題   the reaction of lignin with chlorine to give dioxin as the by-product 木質素會和氯產生反應，生成二噁英

2,3,7,8- tetrachlorodibenzo-p-dioxin 四氯雙苯环二噁英 1 2 3 4 5 6 7 8 9 10

37.2 Some Green Chemistry Practices (SB p.212) Dioxin is a carcinogen二噁英是一種致癌物  causes various health problems 引致許多健康問題  can pass along food chain and accumulate in food products like dairy products, pork, beef and fish 會沿食物鏈積聚在食物產品中，例如奶類食品、豬 肉、牛肉和魚類 In view of this, the use of chlorine in the process has been discouraged 在紙的製造過程中已禁止使用氯

德豬肉二噁英含量超標 2011-01-12 09:43:00 德國農場飼料受二噁英污染事件繼續擴大，繼雞蛋及雞肉後，當局首次在豬肉亦驗出二噁英的含量超標，部分相信已經流出市面。驗出可致癌物質二噁英含量超標的豬隻，是來自北部下薩克森州費爾登附近一間豬場，500多隻豬中，有140隻二噁英含量超標五成，都是食了有毒的飼料。當局已經下令銷毀，但相信部分受污染的豬肉已經流入市面。而當局亦抽驗過同區另一間農場的豬肉，證實沒有問題。當局售賣豬肉副生品的商販，生意暫時未有受到太大影響。今個月初，德國的雞蛋及雞肉驗出二噁英含量超標，當局指飼料生產商使用製造生物柴油時產生的工業物料生產飼料，令飼料受污染。香港食物安全中心會向德國及歐盟有關當局了解事件，並抽取豬肉樣本化驗，以及密切留意情況。

據新華社  由於下薩克森州一家與二惡英污染事件有關的動物飼料廠涉嫌隱瞞資訊，德國當局15日下令934家農場關閉，等待檢查。      德國檢方當天搜查這家飼料廠多處辦公室。檢方女發言人卡羅琳·卡斯塔尼亞說，他們主要搜尋貨物發送的文件資料，原因是這家企業向一些農場提供可能遭二惡英污染的飼料，但隱瞞這些資訊。      德新社報道，這家企業總部位於距漢堡市西南大約150公里的達默鎮，在附近城鎮還有兩家分廠。按照聯邦官員的說法，它向4個州的110家養雞場、651家養豬場及其他一些農場提供飼料。      德國去年12月底曝出二惡英污染事件，隨後蔓延至全國10多個州。大約5000家農場一度遭關閉，經檢驗無恙後，超過4000家現已重新運營。      德國農場主聯合會主席格爾德·松萊特納15日說，這次二惡英污染事件預計致使德國農場主損失1億歐元(約合1.3億美元)。（責任編輯：邵希煒）

【明報專訊】新聞撮要﹕ ── 綜合《明報》新聞 德國當局表示，有多達3000噸受污染的飼料送到逾千個家禽和養豬農場，而來自這些農場的數以萬計雞蛋，其後出口到荷蘭，其中約14噸蛋白再由荷蘭運往英國。這些蛋白通常會售給食物製造商，用於製作沙律醬和糕點。 污染事件源於德國北部省份一家化學公司，2010年底將多達3000噸受污染的脂肪酸，供應給25家飼料製造商。2010年12月底，德國一批雞蛋被驗出二噁英含量超出歐盟法定限制的4倍，因而爆出這宗醜聞。有德國傳媒指出，該化學公司早在2010年3月已測出脂肪酸的二噁英含量超標，但測試報告未有送往有關當局，農業部也是在2010年底才得悉測試結果。官員正調查是否有人涉及「不法行為」。 食物安全專員陳漢儀稱，決定扣檢所有入口的德國雞蛋及禽肉，直至確定對二噁英的化驗合格才會放行零售。外界對政府能否杜絕德國禽畜食品在本港零售亦存疑，因每月入口本港的德國蛋平均多達170萬隻、經處理的入口德國禽肉及內臟亦達16萬公斤。

知識增益 二噁英 二噁英（Dioxins）是焚燒廢物過程中產生的一類有毒化學品，亦是化學品和生產過程中的副產品，是最具毒性和持久性的污染物之一。對人類來說，大約90%的二噁英來自食物，其中動物脂肪含量高的牛奶、魚、雞蛋和肉類是主要來源。二噁英對健康沒有即時影響，但若長期大量攝入就會導致癌症、影響生育並帶來免疫系統問題，當中對懷孕婦女尤其危險。

Use of H2O2 as a Green Bleaching Agent in Industry 工業上使用過氧化氫作為環保漂白劑 37.2 Some Green Chemistry Practices (SB p.212) Use of H2O2 as a Green Bleaching Agent in Industry 工業上使用過氧化氫作為環保漂白劑 Hydrogen peroxide was used as a bleaching agent in the presence of the TAML iron(III) activators 在 TAML 鐵(III) 活化劑存在的情況下, 過氧化氫用作漂白劑 The TAML activator acts as a catalyst TAML TAML活化劑則作為催化劑  promotes the conversion of hydrogen peroxide into hydroxyl radicals that are involved in the bleaching process 加快過氧化氫轉化為羥基自由基的過程

Use of H2O2 as a Green Bleaching Agent in Industry 工業上使用過氧化氫作為環保漂白劑 37.2 Some Green Chemistry Practices (SB p.212) Use of H2O2 as a Green Bleaching Agent in Industry 工業上使用過氧化氫作為環保漂白劑 The reaction product is water which is harmless 這漂白過程的生成物是無毒的水 The catalytic activity of TAML activators allows TAML 活化劑讓  hydrogen peroxide to break downmore lignin in a shorter time and at a much lower temperature 過氧化氫在較短時間內和較低溫度下分解較多木質素

37.2 Some Green Chemistry Practices (SB p.212) TAML (tetraamido macrocyclic ligands) are made from naturally occurring biochemicals. 可由天然生化物製造而得。 Their presence allows H2O2 oxidation to proceed at much lower temperature and pressure. 較低溫及壓強下讓H2O2進行氧化。 TAML activated peroxide shows attractive dye transfer inhibition attribute. TAML活化過氧化物令鮮艷染料的顏色不被抑制。 TAML are made from naturally occurring biochemicals. the highly selective activator uses the peroxide present in some detergents to hunt and destroy free dye molecules,

Cleaning applications of TAML activators 37.2 Some Green Chemistry Practices (SB p.212) Cleaning applications of TAML activators Bleaching the lignin(木質素) in wood pulp(木槳) Decolorizing the effluent from the pulp and paper and textile industries紡織工業。 Destroying free dye molecules in clothes laundering 洗衣時破壞自由染料分子。 Lignin is a complex array of molecules that holds the cellulose in wood together. It is also responsible for the brown color of paper, like that used for paper grocery sacks. In order to get bright white paper, the lignin must be removed. The paper industry traditionally used chlorine for this purpose. In the past 10 years, most of the industry has moved to chlorine dioxide, which minimizes the formation of dioxins that result from chlorine treatment. Bleaching with TAML® activators and hydrogen peroxide offers another advance in the greening of the process, by completely eliminating the formation of dioxin waste.

Hydrogen peroxide as bleaching agent 過氧化氫用作漂白劑 37.2 Some Green Chemistry Practices (SB p.212) Hydrogen peroxide as bleaching agent 過氧化氫用作漂白劑 Laundry bleaches(家用漂白) fall into two categories: “chlorine” bleaches and “oxygen” bleaches. 家用漂白可分為氯漂和氧漂兩大類。 When water is added to oxygen bleaches such as sodium carbonate peroxide (2Na2CO3 · 3H2O2), sodium peroxide (Na2O2), or sodium perborate (NaBO3), hydrogen peroxide is released. 當水加入2Na2CO3 · 3H2O2, Na2O2 和NaBO3, 釋出過氧化氫。 Most oxygen bleaches work best in hot water. 氧漂於熱水效果最好。

Hydrogen peroxide as bleaching agent 過氧化氫用作漂白劑 37.2 Some Green Chemistry Practices (SB p.212) Hydrogen peroxide as bleaching agent 過氧化氫用作漂白劑 Hydrogen peroxide is a greener alternative to chlorine bleaches. 相對氯漂而言, 過氧化氫為比較綠的替代品。 Primary decomposition products: water and oxygen . (主要分解生成物是水和氧): In the process of decomposing, H2O2 releases free radicals that oxidize colored stains or pigments, rendering them colorless – bleached. 分解過程中, H2O2釋出自由基將顏色污點或色塊氧化變成無色。

37.2 Some Green Chemistry Practices (SB p.212) Why not replace chlorine bleaches with hydrogen peroxide?為何不用過氧化氫取代氯漂白劑? Any molecules in the vicinity that are exposed to decomposing H2O2 get exposed to reactive free radicals, so some unwanted chemistry might accompany the desired oxidation. 於周遭的分子亦會和自由基發生反應生成非必要的氧化反應。 Successful bleaching with H2O2 requires higher temperature, pressure and longer reaction time. 需要較高溫度, 壓強和較長的反應時間方可完成漂白程序。 Check Point 37-2

37.2 Some Green Chemistry Practices (SB p.213) Check Point 37-2 (a) What is a hydroxyl radical?羥基自由基是甚麼？ (b) Hydroxyl radical bleaches by oxidation. Explain its oxidizing property. 羥基自由基藉著氧化作用進行漂白作用。試解釋為甚麼羥基自由基具有漂白特性。 (a) Hydroxyl radical carries an odd electron (i.e. unpaired electron) on the oxygen atom . 羥基自由基中的氧原子含有一個不成對電子。

37.2 Some Green Chemistry Practices (SB p.213) Check Point 37-2 (b) Hydroxyl radical bleaches by oxidation. Explain its oxidizing property. 羥基自由基藉著氧化作用進行漂白作用。試解釋為甚麼羥基自由基具有漂白特性。 (b) The hydroxyl radical is highly reactive. It tends to accept an electron in reaction so as to achieve an octet electronic configuration of the oxygen atom. That explains why it is a strong oxidizing agent. 羥基自由基是高度活潑的，它傾向在反應中接受一個電子，以達致氧原子的八隅體電子組態。這解釋了為甚麼羥基自由基是一種強氧化劑。

Ionic liquids and green chemistry離子液體和綠色化學 STS Zone (p.213) Ionic liquids and green chemistry離子液體和綠色化學 Ionic liquids (or more correctly non-aqueous ionic liquids) have been known for many years. As their name implies, they are ionic in nature but exist as liquids at room temperature and pressure. This is due to the poor packing of ions in the lattice. Ionic liquids usually consist of large, non-spherical cations and various anions. 離子液體(或非水性離子液體)已被發現了多年。正如它們的名稱，它們含有離子。但是它們在常溫常壓下並不如其他離子化合物般呈固態，而是呈液態。這是由於晶格內離子呈不規則的排列。離子液體通常含有大的而非球狀的陽離子，並含有不同的陰離子。

Much of the research of ionic liquids is related to their use to replace organic solvents in chemical reactions and processes. Given a material - an organic substance, a plastic, or even a rock - researchers believe you will be able to find an ionic liquid that is able to dissolve it. Many chemical processes use volatile organic liquids as solvents. These organic solvents evaporate easily into the surrounding air and cause air pollution. It is also a waste of materials. Besides, organic solvents are often flammable and cause safety concerns. Ionic liquids have the advantages that they are neither volatile nor flammable. There is much scope for the development of using ionic liquids to replace organic solvents. 很多離子液體的研究都和有機溶劑的化學反應和過程有關。如果有 一種物料一一有機物質、塑膠、甚至是石頭一一科學家都相信你能夠找 到可以把它們溶解的離子液體。很多化學過程利用易揮發的有機液體作為溶劑。這些有機溶劑容易蒸發到空氣中，造成空氣污染，並且浪費物料。此外，有機溶劑通常都是易燃的，這令人關注安全問題。離子液體的優點是它們既不易揮發，又不易燃。因此，利用離子液體取代有機溶液還有很大的發展空間。

離子液體中常見的離子 Ions commonly found in ionic liquids STS Zone (p.213) 陽離子cation: Ph-N+(CH3)3 陰離子Anions: BF4- PF6- A12C17- (CF3SO2)N- 離子液體中常見的離子 Ions commonly found in ionic liquids

STS Zone (p.213) Questions問題: 1.列出使用有機溶劑產生的環境問題。 List some environmental problems caused by the use of organic solvents. 2.化學反應中，利用離子液體作為溶劑有甚麼好處? What are some of the advantages of using ionic liquids as solvents in chemical reactions? 有機溶劑容易蒸發到空氣中，造成空氣污染；它們都是易燃的，這令人關注安全問題。 Organic solvents evaporate easily into the surrounding and cause air pollution. Also, they are flammable and cause safety concerns. 離子液體既不易揮發，又不易燃。因此，它們可取代有機溶劑。 Ionic liquids are neither volatile nor flammable so that they can replace organic solvents.

STS Zone (p.213) Questions問題,,: 3.試以離子液體的結構，解釋為甚麼它們在常溫常壓下呈液態。 Explain the existence of ionic liquids as liquid state at room temperature in terms of their structures. 3. 離子液體通常含有大而非球狀的陽離子，並含有不同的陰離子。這使晶格內離子呈不規則的排列。 Ionic liquids consist of large, non-spherical cations and various anions so that the ions pack poorly in the lattice.

STS Zone (p.213) Ionic Liquid 離子液體– Green Chemistry

S.T.S ZONE 地帶 P .213 Ionic Liquid 離子液體– Green Chemistry

S.T.S ZONE 地帶 P .213 Ionic Liquid 離子液體– Green Chemistry In general, ionic liquids consist of a salt where one or both the ions are large, and the cation has a low degree of symmetry. 通常離子液體是不同的大體積電荷或低對稱陽離子所組成的鹽。 These factors tend to reduce the lattice energy of the crystalline form of the salt, and hence lower the melting point. 因以上因素令其晶格焓下降, 熔點亦因此下降。 © 2000 IUPAC, Pure and Applied Chemistry 72, 1391–1398

S.T.S ZONE 地帶 P .213 Ionic Liquid 離子液體– Green Chemistry CONCLUSIONS結論 Because the properties and behavior of the ionic liquid can be adjusted to suit an individual reaction type, they can truly be described as designer solvents. 因為離子液體之組合可調節以適應不同反應模式,故它們被稱為設計者液劑。　 We have shown that, by choosing the correct ionic liquid, high product yields can be obtained, and a reduced amount of waste can be produced in a given reaction. Often the ionic liquid can be recycled, and this leads to a reduction of the costs of the processes. 我們可選擇合適的離子液體, 令反應中獲得高產率, 減少廢物。離子液體亦經常可回收, 降低過程中的成本。

S.T.S ZONE 地帶 P .213 Ionic Liquid 離子液體– Green Chemistry It must be emphasized that reactions in ionic liquids are not difficult to perform and usually require no special apparatus or methodologies. The reactions are often quicker and easier to carry out than in conventional organic solvents. 離子液體的使用無需特別儀器或方法。 而且比日常之有機溶劑之反應更快和容易。

S.T.S ZONE 地帶 P .213 Ionic Liquid 離子液體– Green Chemistry Ionic liquids have no measurable vapor pressure(離子液體沒有可量之蒸氣壓), and hence can emit no volatile organic compounds (VOC揮發性有機化合物). They have attracted, quite justifiably, enormous attention as media for green synthesis. 它們可作為綠色合成的媒體。 The first room-temperature ionic liquid [EtNH3]+[NO3-] (m.pt. 12 °C) was discovered in 1914. ***2010 ALPI#6 ---- Ionic Liquid 離子液體***

Immiscibility with water separations與水不混溶液而分離 http://www.ngimat.com/pdfs/Ionic_Liquids.pdf Not Just Green不單綠色 Ionic liquids not only provide a less hazardous solvent option, they also have useful industrial applications: 離子液體不但可以減少使用有害溶劑，他們也應用於工業應用： Dissolution of metal oxides ore, refractory,and metal oxide processing (溶解金屬氧化物礦石，耐火材料，金屬氧化物加工 Immiscibility with water separations與水不混溶液而分離 Dissolve polar and non-polar hydrocarbons flexibility in organic synthesis (有機合成中, 靈活溶解極性和非極性的烴)

Note--s7_ch37_GreenChem_IonicLiquid 2010 PI#6-10% Read the passage below and answer the questions that follow: 閱讀以下一段文字，並回答隨後的問題: Ionic Liquids離子液體 Non-aqueous ionic liquids, or simply ionic liquids, generally have low vapour pressure and low melting point. They are becoming popular solvents in organic synthesis. 非水離子液體(簡稱離子液體)普遍有低蒸氣壓和低熔點。它們在有機合成中，逐漸成為較多人使用的溶劑。

[emim]+ Note--s7_ch37_GreenChem_IonicLiquid 2010 PI#6-10% Ionic Liquids離子液體 Ionic liquids mainly consist of ions, and at least one of them is a bulky organic ion. 1–Ethyl-3-methylimidazolium tetrafluoroborate ([emim]BF4) is an example of ionic liquids. 離子液體主要由離子(多於一種)組成，其中最少有一種是龐大的有機離子。1-乙基-3-甲基咪唑四氟硼酸鹽(1–Ethyl-3-methylimidazolium tetrafluoroborate) ([emim]BF4)便是一個離子液體的例子。 [emim]+

Note--s7_ch37_GreenChem_IonicLiquid 2010 PI#6-10% Ionic Liquids離子液體 Ionic liquids are also described as 'designer solvents' because their properties such as melting point, viscosity and hydrophobicity can be modified by changing the structure of their component ions. This enables them to meet the particular requirements of a synthesis. 離子液體亦被描述為「量身設計溶劑」，因為改變其組成離子的結構，可以改變它們的性質(例如:熔點、黏滯度和疏水性等)來滿足某個合成的特定要求。

Note--s7_ch37_GreenChem_IonicLiquid 2010 PI#6-10% Ionic Liquids離子液體 (a) 1–Ethyl-3-methylimidazolium cation, [emim]+, is stabilised by dispersion of its positive charge. Draw structure(s) to show the dispersion of charge in [emim]+. 由於1-乙基-3-甲基咪唑陽離子([emim]+)所帶正電荷被分散，令它變得穩定。繪出(一個或多個)結構來顯示[emim]+的電荷的分散。

This leads to poor packaging or the ions in solid state. Note--s7_ch37_GreenChem_IonicLiquid 2010 PI#6-10% (b) (i) Some ionic liquids, including [emim]BF4, are liquid at room temperature. They are called 'room-temperature ionic liquids'. Account for the low melting point of such ionic liquids. 有些離子液體(包括[emim]BF4)在室溫時是液體。它們被稱為 「室溫離子液體」。解釋為什麼這些離子液體有低熔點。 The size difference between the cation and anion is very large. 陰離子與陽離子的體積差異十分大。 1 This leads to poor packaging or the ions in solid state. 令這些離子在固態中裝填得不夠緊密。 1/2 The dispersion of the charge of the cation (due to resonance) also weakens the ionic interaction. 陽離子的電荷(因共振而)被分散，令離子間的相互作用減弱。

In [emim]BF4, the interparticle attraction is ionic bond. Note--s7_ch37_GreenChem_IonicLiquid 2010 PI#6-10% Ionic Liquids離子液體 (b) (ii) Explain why [emim]BF4 has low vapour pressure. 解釋為什麼[emim]BF4 有低蒸氣壓。 In [emim]BF4, the interparticle attraction is ionic bond. 在[emim] BF4,中，粒子間的引力是離子鍵。 1 The strong interparticle attraction prevents the ions from escaping from the liquid phase to give the vapour. 由於粒子間的引力強，令離子不容易從液相逸至氣相。 1/2

1/2 1 Note--s7_ch37_GreenChem_IonicLiquid 2010 PI#6-10% Ionic Liquids離子液體 (iii) Replacing the ethyl group in [emim]BF4, by a butyl group gives another ionic liquid [bmim]BF4. Which of these two ionic liquids would you expect to have a higher viscosity? Explain. 以丁基取代在 [emim]BF4 中的乙基，得到另一個離子液體 [bmim]BF4。這兩個離子液體中的哪一個會有較高的黏滯度? 請解釋。 [bmim]BF4, is more viscous [bmim] BF4,的黏滯度較高。 1/2 The increase in size of the alkyl group leads to an increase in strength of Van der Waals forces and relative movement of the species is thus restrictedu 烷基的體積增大令范德華力增強，所以物種的相對位移也會受限制。 1

Note--s7_ch37_GreenChem_IonicLiquid 2010 PI#6-10% (c) Suggest THREE advantages of using ionic liquids over using organic solvents such as CH3COCH3 and (C2H5)2O in organic synthesis. Explain your answer. 提出三項在有機合成中使用離子液體較使用有機溶劑(例如: CH3COCH3和 (C2H5)2O優勝之處。解釋你的答案。 (3 marks) Any THREE ofthe following: 下列任何三項: - Tunability (可調性) : By varying the cation/anion ratio, type and alkyl chain length, properties such as acidity/basicity, melting point and viscosity of ionic liquids can be changed to meet particular demands of a reaction 可調性:改變陰離子與陽離子的體積比、烷基的鏈長,可改變離子液體的性質,例 如:酸鹼性、熔點、黏滯度等，以符合反應的特定要求。 - Wide liquid range (液態域) : Ionic liquids have low melting point, and high boiling point (as revealed from their low vapour pressure). They provide the opportunity to carry out high-temperature reactions at low pressure. 寬的液態域:離子液體具低熔點，卻有高沸點(由於它們的蒸氣壓低) ，因此它們可用作在低壓強下進行高溫反應的介質。

(Accept other correct answers.) Note--s7_ch37_GreenChem_IonicLiquid 2010 PI#6(c) - Low combustibility : Due to their low vapour pressure, ionic liquids usually have low flash points. 低可燃性:由於離子液體的蒸氣壓低，它們一般有低的閃點。 _ Low vapour pressure: Volatile organic compounds can easily be removed from the ionic liquids by simple distillation. 低蒸氣壓:利用簡單蒸餾法可把易揮發的有機溶劑從離子液體中分離出來。 Electrolytic property: They can be used as a medium for reactions involving ionic reagents. 電解性質:用作涉及離子試劑的反應的介質。 (Accept other correct answers.)

Any ONE of the following: 下列任何一項: Note--s7_ch37_GreenChem_IonicLiquid 2010 PI#6-10% Ionic Liquids離子液體 (d) Suggest ONE reason which prevents ionic liquids from replacing organic solvents in organic synthesis. 提出一項有礙離子液體在有機合成中取代有機溶劑的理由。(l mark) Any ONE of the following: 下列任何一項: 1 - The synthesis of ionic liquids can be very costly. 合成離子液體的價格可能十分高昂。 - The disposal of ionic liquids can pose greater harm to the environment than organic solvents. 與有機溶劑相比，排放離于液體對環境可能導致較嚴重的危害。

Atom economy 原子經濟性 P.214-資訊角2 For your interest2 An "atom economy" approach to the green manufacturing of chemical products (like pharmaceuticals, plastics or pesticides) was suggested. In the approach, the syntheses would be designed so that all reactant atoms end up as desired products, not as wasteful by-products. In this way, money as well as materials are saved. Also, undesired products, which require treatment or disposal, would not be produced. 有人提出以「原子經濟性」的綠色方法製造化學產品(例如藥物、塑膠或殺蟲劑)。利用這個方法，合成過程需要特別設計，合成所有反應物原子最後都變成有用的生成物，而不是沒有用的副生成物。這個方法既可以節省 金錢和物料，又不會產生廢物。

= Atom economy 原子經濟 P.214-資訊角2 For your interest2 High Yield高產率  good reaction好反應????　 副產品的多少????　the amount of side-products ?????? Molecular mass of the desired product 要求生成物的分子量 % atom economy 原子經濟百分比 = x 100% Molecular mass of all product 所有生成物的分子量 Green reation ‘s atom economy should be as high as possible. 綠色反應的原子經濟是盡量高  Alternate routes 另闢路徑

P.215 The synthetic reaction of propylene oxide is : 環氧丙烷 的合成反應如下所示: Step 1 : CH2CH=CH2 + HOCl  CH3CH(OH)CH2Cl Step 2 : CH3CH(OH)CH2Cl + Ca(OH)2  2 + CaCl2 + 2H2O New Route(新路徑) : CH2CH=CH2 +H2O2 + H2O Catalyst 催化劑

P.214 Step 1 : CH2CH=CH2 + HOCl  CH3CH(OH)CH2Cl (a) Name the reaction mechanism in step 1. 步驟1的反應機理的名稱 electrophlilic addition親電加成 (b) Calculate the atom economy() for the two methods .計算兩個方法的原子經濟。 (c) Beside atom economy , is the new route a ‘greener ; process?Explain.除了原子經濟外, 新路徑是否比較綠色的方法?試解釋。

(b) 52.5 42 96.5 Step 1 : CH3CH=CH2 + HOCl  CH3CH(OH)CH2Cl Step 2 : 2CH3CH(OH)CH2Cl + Ca(OH)2  2 + CaCl2 + 2H2O 74 18 58 111 44.1 atom economy(原子經濟)= _______% 58 CH3CH=CH2 +H2O2 + H2O Catalyst 催化劑 42 34 18 atom economy(原子經濟)= _______% 76.3

Full-scale production of plastics from corn 大規模生產栗米塑膠 發酵& 凝結 聚乳酸 Polylactic acid 葡萄糖 丙交酯 Fermentation to lactic acid Condensation to dimer lactide  di-ester of lactic acid 乳酸

P.217 Exercises練習 1. What is Green Chemistry 「綠色化學」是甚麼? P .208或 筆記 2. Green solvent /環保溶劑? Non-toxic, ease of recycling of solvents, not easily vaporize , non-hazardous 無毒、容易循環再用、不易揮發和不危險 Ionic liquid離子液體-P.213-214 AL2010 PI#6-10%

P.217 Exercises練習37#3 繪畫水的壓強對溫度的線圖，並顯示水呈固態、液態和氣態的範圍。在圖上標示水的臨界點，並顯示超臨界水存在的範圍。 Sketch a pressure-temperature diagram of water showing the existence of solid, liquid and gaseous states. Mark the critical point of water on your diagram and indicate regions representing the existence of supercritical water.

P.217 Exercises練習37 3. Critical point of water 超臨界水 SFC water 3. Critical point of water Book 1 11.5 Hydrogen bonding (p.288)

C4H8+ 3O2 C4H2O3 + 3H2O P.217 Ch37-Exercises練習#4 (a) (i)苯(C6H6)被氧氧化為馬來酐 (C4H2O3)。寫出涉及反應的化學方程式，反應的副生成物只有二氧化碳和水。 Write the chemical equation for the oxidation of benzene (C6H6) by oxygen to maleic anhydride (C4H2O3). The by­products are carbon dioxide and water only. (ii)另一個合成馬來酐的方法是，利用氧把丁烯氧化為馬來酐。寫出涉及反應的化學方程式，反應的副生成物只有水。 In another synthesis of maleic anhydride using butene, write the chemical equation for the oxidation of butene by oxygen to maleic anhydride (C4H2O3).. The by-product is water only. 4(a)i. benzene苯 maleic anhydride馬來酐 C6H6+ O2 C4H2O3 + CO2 + H2O 4(a)ii. 丁烯+氧馬來酐 + 水 butene + oxygen  maleic anhydride+ H2O C4H8+ 3O2 C4H2O3 + 3H2O

P.217 Ch37-Exercises練習#4 (b) 計算原子經濟性的百分比的方程式是: 100% x (要求的生成物的相對分子質量所有反應物的相對分子質量) The percentage of atom economy is 100% X (relative molecular mass of desired products  relative molecular mass of all reactants). (i) 分別計算由苯氧化為馬來酐，及由丁烯氧化為馬來酐的原子經濟百分比。 Calculate the percentage of atom economy of the oxidation of benzene to maleic anhydride, and the oxidation of butene to maleic anhydride. (ii) 指出哪個方法製造馬來酐較合乎原子經濟的原則。 State which of the two routes to make maleic anhydride is a better choice in terms of atom economy.

4(a)i. benzene  maleic anhydride 苯馬來酐 P.217 Ch37-Exercises練習#4 4(a)i. benzene  maleic anhydride 苯馬來酐 C6H6+ O2 C4H2O3 + CO2 + H2O 2 2 % atom economy of the oxidation of benzene to maleic anhydride 由苯氧化為馬來酐的原子經濟百分比 44.1% = (98.0)/(78.0+144.0) * 100% =

4(a)ii. 氧+ 丁烯馬來酐 + 水 butene maleic anhydride+ H2O P.217 Ch37-Exercises練習#4 4(a)ii. 氧+ 丁烯馬來酐 + 水 butene maleic anhydride+ H2O C4H8+ 3O2 C4H2O3 + 3H2O % atom economy of the oxidation of butene to maleic anhydride 由丁烯氧化為馬來酐的原子經濟百分比 = (98.0)/(56.0+96.0) * 100% = 64.5%

Green Chemistry 綠色化學 2006PII#4(c)- H2 (clean energy source 潔淨能源) 2007PI#10-Fats/Oils - 20% ---- Car fuels(汽車燃料)-Essay 2008pI#10 Apply Green Chemistry in industry(工業)-Essay - 20% 2008 PII#7(b)(i)(ii)-Polyimines (聚亞胺 )--- 9% 2009pII#4(c)(iv) – 4 reasons of e.g of green chem. 2010PI#6(a)(b)(i,ii,iii)(c)(d) – Ionic liquids離子液體

nucleophilic addition 親核加成 2008PII#7(b) Polyimines (聚亞胺)—conductor 導電體 Part 08_p.27 7. (b) (i) 下列反應生成有機中間物 J , 它藉消去水生成了產物K。 The following reaction gives an organic intermediate J which by elimination of water gives product K.  (I) 分別寫出 J 和 K 的。Give the of J and that of K. 1,1 structure結構 nucleophilic addition 親核加成 dehydration脫水 (II) 概述生成 J 的機理。 Outline a mechanism for the formation of J.

nucleophilic addition of carbonyl group 羰基的親核加成反應 2008PII#7(b)(i) Polyimines (聚亞胺)—conductor 導電體 Part 08_p.27  (II) 概述生成 J 的機理。 Outline a mechanism for the formation of J. 機理mechanism 2 nucleophilic addition of carbonyl group 羰基的親核加成反應

nucleophilic addition of carbonyl group 羰基的親核加成反應 (II) Outline a mechanism for the formation of J.  H+ -H+ nucleophilic addition of carbonyl group 羰基的親核加成反應

2008PII#7(b)(ii) Polyimines (聚亞胺)—conductor 導電體 Part 08_p.27 (ii) 聚亞胺有共軛性甚高的骨幹，屬於一類導電性聚合物，並且用途廣泛 (如電子及光電子器件等)。一個聚亞胺 L 的部分結構如下: Polyimines, with a highly conjugated backbone, belong to a type of conducting polymer which has a wide variety of applications, such as in electronics and optoelectronics. A part of the structure of a polyimine L is shown below: Add C=N  (I) 繪出 L 的重複單位的結構。 Draw the structure of the repeating unit of L. (II) 繪出 L 的單體(一個或多個)的結構。 Draw the structure of the monomer(s) of L. (III) 提出兩個理由說明為什麼從單體生成 L 是綠色化學的例子。 Suggest TWO reasons why the formation of L from its monomer(s) is an example of green chemistry.

 (I) 繪出 L 的重複單位的結構。 Draw the structure of the repeating unit of L. 2008PII#7(b)(ii) Polyimines (聚亞胺)—conductor 導電體 Part 08_p.27  (I) 繪出 L 的重複單位的結構。 Draw the structure of the repeating unit of L. (II) 繪出 L 的單體(一個或多個)的結構。 Draw the structure of the monomer(s) of L.

2008PII#7(b)(ii) Polyimines (聚亞胺)—conductor 導電體 Part 08_p.27  (II) 繪出 L 的單體(一個或多個)的結構。 Draw the structure of the monomer(s) of L. H2 O 1+1

2008PII#7(b)(ii) Polyimines (聚亞胺)—conductor 導電體 Part 08_p.27 (III) 提出兩個理由說明為什麼從單體生成 L 是綠色化學的例子。 Suggest TWO reasons why the formation of L from its monomer(s) is an example of green chemistry.  green chemistry綠色化學 + nH2O(l) (III) 這反應只產生L和水，即是沒有生成有毒產物。 The reaction gives only L and water, i.e. no toxic products are formed. 1 The reaction has a high atom economy. 這反應有高原子經濟量。

Joint-US – 9 points, 筆記有十二項 HKEAA列出五項 (考試要求四點) Write an essay on the application of the principles of green chemistry in industry. 2008pI#10寫一篇文章討論綠色化學各原理在工業上的應用。-20% 10. 化學知識(10分) 本題預期考生能就不少於四個綠色化學原理(總數=12)，討論它們在工業上的應用。 Candidates are expected to discuss the application of at least four of the principles (Total :12)of green chemistry in industry. 答案例子: (可接受不同的應用，閱卷員需基於綠色化學的原理，予以評分。) Examples (A variety of applications can be accepted. Markers are required to make their own judgement based on the principles of green chemistry.) Joint-US – 9 points, 筆記有十二項 HKEAA列出五項 (考試要求四點)

- Haber process in the manufacture of ammonia. 以哈柏法生產氨。 Write an essay on the application of the principles of green chemistry in industry. 2008pI#10寫一篇文章討論綠色化學各原理在工業上的應用。-20% (1) 原于經濟性:設計合成法時,盡可能把過程中使用的物料都納入最終產物中。 Atom economy: synthetic methods should be designed to maximise the incorporation of all materials used in the process into the final product 符合原子經濟性的工業過程計有: Atom economy industrial processes: - 利用貝克曼重排反應生產尼龍-6。 manufacture of nylon-6 by Beckmann rearrangement - addition reactions, e.g. obtaining saturated fats by catalytic hydrogenation 加成反應, 例如經催化加氫反應得到飽和脂肪。 - Haber process in the manufacture of ammonia. 以哈柏法生產氨。

2008pI#10 Apply Green Chemistry in industry(工業)-Essay - 20% (2) 採用危險性較低的合成法:設計合成法時，盡可能使用對人類與環境無害或微毒性物質 此原則亦適用於合成法中的產物。 (2) Less hazardous chemical synthesis: wherever practicable, synthetic methods should be designed to use and generate substances that possesses little or no toxicity to human health and the environment -使用超臨界CO2作乾洗溶劑和脫咖啡因溶劑，來代替有害的有機溶劑如CH2Cl2及苯等。 - use of supercritical CO2 in decaffeinating coffee and in dry cleaning : replacing harmful organic solvents such as CH2Ch, benzene by non-polluting supercritical CO2

(3) 安全溶劑及輔助物:盡可能避免使用輔助物(如溶劑、分離試劑等) ;需要時，應盡可能使用無毒輔助物。 2008pI#10 Apply Green Chemistry in industry(工業)-Essay - 20% (3) 安全溶劑及輔助物:盡可能避免使用輔助物(如溶劑、分離試劑等) ;需要時，應盡可能使用無毒輔助物。 (3) Safer solvents and auxiliaries: the use of auxiliary substance (e.g. solvents, separating agents) should be made unnecessary wherever possible and innocuous when used. -無溶劑合成法:例如把單體與催化劑研磨以生產PMMA。 - solvent-free syntheses: e.g. manufacture of PM MA by grinding monomers with a catalyst

2008pI#10 Apply Green Chemistry in industry(工業)-Essay - 20% (4) 催化反應:使用催化試劑(選擇性愈高愈好)遠勝於使用計量試劑。 (4) Catalysis: catalytic reagents (as selective as possible) are superior to stoichiometric reagents - 以哈柏法生產氯 - Haber process in the manufacture of ammonia -使用生物催化劑和不對稱催化劑。 - biocatalysts and asymmetric catalysts 計量試劑 – 通常會過量 而產生廢物 stoichiometric reagents – use in excess and produce wastes. catalytic reagents :They can be regenerated at the end of reaction and can be reused. 催化試劑 : 反應後期會再生和可重用。

2008pI#10 Apply Green Chemistry in industry(工業)-Essay - 20% 5) 具能源效益的設計:應考愚化學過程耗用能量對環境及經濟的影響，並應減至最低。合成 應盡量在接近室溫及常壓下進行。 (5) Design for energy efficiency: Energy requirements of chemical processes should be recognised for their environmental and economic impacts, and should be minimised. If possible synthetic methods should be conducted at ambient temperature and pressure - use of fuel cells使用燃料電池。 - replacing AlCl3 by partially dealuminated 39Y zeolite catalyst以部分脫鋁39Y沸石催化劑來代替AlCl3 (Accept other examples that illustrate the application of the principles of green chemistry接受其他可說明應用綠色化學原理的例子。.) HKEAA 印錯

Part 08_p.31-- 2009pII#4(c)…..(iv) – 4 reasons of e.g of green chem. Compound B (m.p. 39oC) and compound D (m.p. 42oC) react in the presence of a small amount of NaOH(s) to give compound E. The E obtained can be purified by recrystallisation from 90% ethanol. 化合物B (熔點 39°C) 和 化合物D (熔點42°C) 於少量NaOH(s)下反應生成化合物 E. E 可用90%乙醇重結晶法淨化而得。 (6%) (i) Given that the relative molecular masses of B and D are 132.0 and 166.0 respectively, calculate the atom economy of the reaction. 已知 B 和D的相對分子量分別為132.0和166.0。計算反應的原子經濟性。

Part 08_p.31-- 2009pII#4(c)…..(iv) – 4 reasons of e.g of green chem. (i) Given that the relative molecular masses of B and D are 132.0 and 166.0 respectively, calculate the atom economy of the reaction. 已知 B 和D的相對分子量分別為132.0和166.0。計算反應的原子經濟性。 1 = = 94.0%

Part 08_p.31-- 2009pII#4(c)…..(iv) – 4 reasons of e.g of green chem. 132 166 280 2.64 g 4.40 g 3.32 g (ii) In a typical experiment, 2.64 g of B and 3.32 g of D yielded 4.40 g of E. Calculate the percentage yield of E. 傳統的實驗裏, 2.64 g的B和3.32 g 的D可生產4.40 g的 E。計算E的產率百分比。 No. of moles of B used所用B的摩爾數= No. of moles of D used所用D的摩爾數= No. of moles of E obtained生成E的摩爾數= Yield of reaction反應的百分產率= (0.0157 / 0.02) =78.5%

Part 08_p.31-- 2009pII#4(c)…..(iv) – 4 reasons of e.g of green chem. (iii) Give FOUR reasons why this reaction is considered as an example of green chemistry. 舉出四個原因上述反應可作為綠色化學的例子 Any FOUR of the following: 以下任何四項: - The reaction has high atom economy 這反應具有高原子經濟性 - The reaction has a high yield 這反應的百分產率高 - The reaction does not require the use of solvent 這反應毋須使用溶劑 - A catalyst (NaOH(s)) is used這反應使用了催化劑(NaOH(s) ) - The other product (H2O) is non-toxic 副產物(H2O)不帶毒性 2

Caffeine咖啡因-P.225#20(a),(b),(c) – UCLES 2003 咖啡因是種興奮劑，可以在咖啡、茶和可樂中找到。以下是咖啡因的結構: Caffeine is a stimulant found in coffee and tea. It is also added to cola drinks. The structure of caffeine is given below. (a) (i) 在以上的結構中，用星號標示鍵角為109o 的碳原子。 On the structure above, label (with a *) a carbon atom with bond angles of 109°. (ii) 同樣在以上的結構中，圈出酰胺基。 Also on the structure above, draw a circle round an amide group. -sp3

Caffeine咖啡因-P.225#20(a),(b),(c) – UCLES 2003 利用溶劑從固態咖啡和茶中提取咖啡因,便可以製成不含咖啡因的咖啡和茶。 以下工業用的溶劑中，哪個最適合用來製造不合咖啡因的咖啡和茶，並提出兩個原因: Decaffeinated coffee and tea are made by extracting the caffeine from solid coffee or tea using a solvent. Suggest, with two reasons, which of the following industrial solvents would be the most suitable. 苯 benzene 碳氫化合物，如環己烷 a hydrocarbon , such as cyclohexane 液態二氧化碳 liquid carbon dioxide O=C=O Liquid carbon dioxide 液態二氧化碳 Reason 1: Caffeine contains polar amide and amine groups and hence is soluble in liquid carbon dioxide which is also polar. Reason 2: After extraction, carbon dioxide can be easily removed since it is very volatile. 理由1: 咖啡因含有極性酰胺和胺基團, 所以可溶於極性的二氧化碳。 理由2: 萃取後, 二氧化碳因其高揮發性故極易移除。

C8H10N4O2 - p.210 Caffeine咖啡因-P.225#20(a),(b),(c) – UCLES 2003 (i) 寫出咖啡因的分子式。 State the molecular formula of caffeine. (ii) 計算咖啡國的相對分子質量。 Calculate the relative molecular mass of caffeine. (iii) 一罐體積為330 cm3的可樂中含有50 mg的咖啡因。計算咖啡因的濃度,以mol dm-3 . A can of cola contains 50 mg of extracted caffeine in a volume of 330 cm3. Calculate the concentration of caffeine in mol dm-3 C8H10N4O2 - p.210 分子量=194 可樂----50mg /330cm3 [Caeffeine]=???? [咖啡因Caffeine]=7.8 x 10-4M

References http://www.chem.leeds.ac.uk/People/CMR/moreco2.html dbweb.liv.ac.uk/ltsnpsc/devprojs/resources/thermodynamics/energetics/workshop/Supercritical CO2.doc http://www.envsolutions.fmc.com/HydrogenPeroxide/ResourceCenter/tabid/351/Default.aspx http://www.sweetmarias.com/decaf.co-2method.html http://www.ul.ie/~childsp/CinA/Issue45/detergent_giants.htm http://www.chem.cmu.edu/groups/Collins/index.html http://acswebcontent.acs.org/home.html

Chapter 37 – Green Chemistry綠色化學 2006PI#5(b)(i),(iv) Little pollution. 少污染 Part 08_p.12-13 2007PI#8 Benzoin安息香 (a)(b)(c)(d) Part 08_p.19 2008PII#6(b) Major product 主生成物 Part 08_p27 2008PII#10 Application of Green Chemistry 綠色化學的應用 Part 08_p. 25 2009PI#4(c) Cycloxene  nylon-6,6 環己烯尼龍-6,6 Part 08_p.29 p.220 F.S.9#10 Green solvent綠色溶劑–離子液體/ionic liquid SuperCritical fluid / 超臨界流體 p.220 F.S.9#11 Atom economy原子經濟 p.220 F.S.9#13 Essay on green chemistry (2008 ALPI#9) in industry Part8-p.25 --- 2008PI(II)#10 (更正) ---- 請好好安排時間多做2遍或以上

Essay : Tip 2011AL Chem Chlorine may be introduced into many organic compounds by suitable reagents and conditions. With this in mind, write an essay. You should give the type of reaction and also outline the mechanism involved where appropriate. 有機化合物可透過不同的試劑和條件加入氯。據此, 寫一篇文章。文中需依以下的機理描述及其方程。 electrophilic addition 親電加成 electrophilic substitution 親電取代 nucleophilic substitution 親核取代 nucleophilic addition 親核加成 free radical substitution 自由基取代 free radical addition 自由基加成

Chlorination Mechanism 氯化機理 electrophilic addition 親電加成 >=< +Cl2 electrophilic substitution 親電取代 benzene ring/苯環 nucleophilic substitution(SN1, SN2) 親核取代 1o, 2oalcohol/醇 nucleophilic addition 親核加成 Carbonyl / 羰基 free radical substitution 自由基取代 alkane烷基, hv / free radical addition 自由基加成 >=< , hv /

By electrophilic addition親電加成 Chlorine may be introduced to alkenes or alkynes by this type of reaction. The reaction rate of this type of reaction is very fast and does not need any catalyst. 烯烴或炔烴加氯是親電加成反應。反應速率很快和無需催化劑。 Mechanism: 機理 For example, 例如: former cation is more stable due to the positive inductive effect of the CH3 group. 前者的陽離子較穩定, 因為CH3基團的正誘導效應。 )

2. By electrophilic substitution親電取代 By this type of reaction, chlorine may be introduced into the benzene ring of aromatic compounds. Since due to the conjugation(resonance) effect in benzene ring making it less reactive than alkenes and alkynes, electrophilic addition can hardly be taken place. By electrophilic substitution, a catalyst is needed. The catalyst should be a halogen carrier e.g. FeBr3, AlCl3 etc. 芳香族化合物加氯入苯環是親電取代反應。因為苯環的共軛(共振)效應令其活性比烯和炔烴低, 難以進行親核加成反應。加入催化劑以親電取代反應進行。催化劑必須是鹵素載體, 例如: FeBr3, AlCl3等 Mechanism: 機理 Cl-Cl + AlCl3  Cl+ + AlCl4-

3. By nucleophilic substitution親核取代 Chlorine may be replaced the -OH in alcohols by this type of reaction. 氯可親核取代反應取代醇的-OH基。 Actually this type of reaction can be subdivided into two different types: SN1 (unimolecular nucleophilic substitution) and SN2 (bimolecular nucleophilic substitution) . 實際上, 親核取代反應可再分為兩類: SN1 (單分子親核取代反應) 和 SN2 (雙分子親核取代反應)

3. By nucleophilic substitution親核取代 For 30 alcohols in acid medium, SN1 reaction dominates. e.g. 30醇於酸性介質中, 以SN1反應為主導, 如: 速決步

3. By nucleophilic substitution親核取代 For 10 alcohols in acid medium, SN2 reaction takes the priority over SN1. 10醇於酸性介質中, SN2反應比SN1反應優先, 如e.g. For 20 alcohols, both SN1and SN2 may dominante according to the conditions. For example, in polar solvent, SN1 dominates. In non-polar solvent, SN2 dominates. 20醇, SN1和SN2因反應條件不同各呈主導。 例如:極性溶劑有利SN1, 而非極性溶劑時SN2則為主導。 ** SN1和SN2加上消去反應互相比較,亦可獨立成為一題essay ** --- 參考課本 Book 3A – Chapter 30 ----

4. By nucleophilic addition親核加成 Chlorine may be introduced into ketones or aldehydes by this type of reaction. The reagent used is PCl5(s) and the condition should be anhydrous. (∵ PCl5(s) hydrolyses in water very easily.) 酮或醛以親核加成反應引入氯。試劑是PCl5(s), 條件為無水狀態。 (∵ PCl5(s)在水中容易水解)

5. By free radical substitution 5. By free radical substitution. 自由基取代 Alkanes react with Cl2 at high temperature or under U.V. to give chloroalkane. For example, 烷烴可於高溫或紫外線下和氯化應生成氯烷。例如: chain initiation 鏈引發作用: chain propagation 鏈繁延作用: chain termination 鏈終止作用:

Mechanism: 機理 6. By free radical addition自由基加成 Other than electrophilic substitution, chlorine may also be introduced to alkenes by free radical addition but the latter needs more activation energy (by hv or high temperature ) . 烯烴亦可以自由基加成反應加入氯, 後者需要較多的活化能。(如hv或高溫) Mechanism: 機理

Part 08_p.11-- 2006pI#4 4. Read the passage below and answer the questions that follow: 閱讀以下文字，並回答隨後的問題: Phosphazenes(磷氮聯) Phosphazenes are a group of phosphorus(V)/nitrogen(III) compounds featuring P=N linkages. They can exist as chains or cyclic structures. The reaction of PCl5 with NH4Cl in chlorobenzene gives a mixture of white solids of cyclic phosphazenes with formula (NPCl2)n in which the dominant species have n = 3 or 4. Cyclic compounds (NPCl2)3and (NPCl2)4 can easily be separated by vacuum distillation, and (NPCl2)3can further be purified by sublimation. Improved synthetic yield of (NPCl2)3 can be obtained from the reaction of PCl5 with N(Si(CH3)3)3 in dichloromethane at lower reaction temperature. 磷氮聯是一組含有P=N連結特徵的磷(V)/氮(III)化合物，它們能以鏈或環結構存在。PCl5與NH4Cl在氯苯中反應，生成白色固體的環磷氮聯混合物，它們的化學式是(NPCl2)n，其中以n=3或4為主要物種。利用真空蒸餾法，可容易地分離出環化合物(NPCl2)3和(NPCl2)4 ;而(NPCl2)3可藉昇華加以提純。 在較低溫度下，PCl5與N(Si(CH3)3)3在二氯甲烷中反應，可得到較佳的(NPCl2)3合成產率。

Part 08_p.11-- 2006pI#4 X-Ray crystallographic study of cyclic compound (NPCl2)3 shows that all phosphorus-nitrogen bonds are of the same length (0.158 nm) but they are significantly shorter than a normal phosphorus-nitrogen single bond (0.177 nm). The chlorine atoms of phosphazenes are reactive towards nucleophiles such as alkoxides or amines, and the reactions usually involve the replacement of Cl by OR or NR2. X射線結晶研究顯示在環化合物 (NPCl2)3中，各磷氮鍵都有相同的長度(0.158 nm)，卻明顯較一般磷氮單鍵(0.177 nm)為短。磷氯聯中的氯原子對親核體(例如烷醇鹽或胺)的反應性高，這些反應一般涉及Cl被OR或NR2置換。

Part 08_p.11-- 2006pI#4 When pure cyclic compound (NPCl2)3 is heated to above 230°C, it gives a polymer (NPCl2)n (n ~ ≧ 15,000), which belongs to the class of compounds called polyphosphazenes. The reactions of polyphosphazenes with nucleophiles provide a very versatile route to some commercially important materials. For instance, treatment of (NPCl2)n with sodium alkoxides, NaOR, yields cross-linked polymers [NP(OR)2]n which have water-resistant properties, and when R=CH2CF3, the polymers are chemically inert and have a number of biocompatible applications. 當純的環化合物(NPCl2)3加熱至高於230°C時，它會生成聚合物(NPCl2)n(n ≧15, 000) , 屬於一類稱為聚磷氮聯的化合物。聚磷氮聯與親核體的反應提供了靈活的途徑，來製造一些極具商業價值的物料。例如(NPChl2)n遇烷醇的鈉鹽(NaOR)生成具抗水性的交聯緊合物[NP(OR2)n]。當R=CH2CF3時，聚合物的化學性質為惰性，並有多項生物兼容的應用。

(i) 3 PCl5 + 3 NH4Cl  (NPCl2)3 + 12 HCl Part 08_p.11-- 2006pI#4 (a) Complete and balance the following equations完成並平衡下列各方程式:(2分) 氯苯 chlorobenzene (NPCl2)3 + 12________ (i) ____ PCl5 + _____NH4Cl 1 (NPCl2)3 + 9_______ 二氯甲烷 dichloromethane (ii) ____ PCl5 + _____N(Si(CH3)3)3 1 (i) 3 PCl5 + 3 NH4Cl  (NPCl2)3 + 12 HCl (ii) 3 PCl5 + 3 N(Si(CH3)3)3  (NPCl2)3 + 9 (CH3)3 SiCl

Part 08_p.11-- 2006pI#4 (b) 提出為什麼要用真空蒸餾法從其他磷氯聯分離出(NPCl2)3和(NPCl2)4等環化合物，而不用簡單蒸餾法。 Suggest why vacuum distillation rather than simple distillation is used to separate the cyclic compounds (NPCl2)3 and (NPCl2)4 from other phosphazenes 磷氮聯在高溫下進行聚合反應。 The phosphazenes undergo polymerisation at elevated temperatures. 1 (c) 繪出下列環磷氮聯的分子結構。 Draw the molecular structure of each of the following cyclic phosphazenes (i) (NPCl2)3 (ii) (NPCl2)4

Vacuum distillation is a method of distillation whereby the pressure above the liquid mixture to be distilled is reduced to less than its vapor pressure (usually less than atmospheric pressure) causing evaporation of the most volatile liquid(s) (those with the lowest boiling points).  This distillation method works on the principle that boiling occurs when the vapor pressure of a liquid exceeds the ambient pressure. Vacuum distillation is used with or without heating the solution. 真空蒸餾是一種使待分離液體上方壓強小於其蒸汽壓的蒸餾方法 。這種方法適用於蒸汽壓大於環境壓力的液體。由於待分離液體沸點降低，真空蒸餾不一定需要加熱。 一個大氣壓下, 二甲基亞碸(Dimethyl sulfoxide)在189°C沸騰。由於瓶內處於真空狀態，圖中的接受瓶只有70°C. (CH3)2SO

vacuum distillation真空蒸餾法-YouTube Video

vacuum distillation真空蒸餾法-YouTube Video

Part 08_p.11-- 2006pI#4(d) +  (ii) 提出為什麼在環磷氯聯(NPCl2)3中， For cyclic phosphazene (NPCl2)3, suggest why， (i) all phosphorus-nitrogen bonds are of the same length. 各磷氮鍵都有相同的長度。 (ii) the Cl atoms are readily replaced by nucleophiles. 各Cl原子均容易被親核體置換。 (3分) Part 08_p.11-- 2006pI#4(d) (i) Resonance occurs in (NPCl2)3. 在(NPCl2)3出現共振。 The π electrons in the P-N bonds delocalise to some extent indicating certain degree of multiple bond character. 各P-N鍵間的π電子發生離域，故這些鍵呈一定程度的重鍵性質。 (ii) +  N is more electronegative than P. The P-N bond is highly polarised. The P atoms, carrying a partial positive charge, are more susceptible to nucleophilic attack leading to the displacement of Cl atoms. 因為N的電負性較P的電負性高，所以PN鍵具高度極性。各P原子帶著部分正電荷，故易受親核體攻擊，從而令Cl原子發生置換反應。

Part 08_p.11-- 2006pI#4 (e) Draw the structure of the repeating unit of the polymer formed from the reaction of polyphosphazene(NPCl2)n with CH3NHz. 繪出從聚磷氯聯(NPCl2)n與CH3NH2反應而生成的聚合物的重複單位的結構。 (1分) (NPCl2)n + 2 CH3NH2 (f) Suggest a biocompatible application of [NP(OCH2CF3)2]n. 提出一項[NP(OCH2CF3)2]n的生物兼容應用。 (1分) Construction of artificial blood vessels and organs / use to cover severe burns and wounds to prevent loss of body fluids and keep germs out.製造人造血管和器官/用以覆蓋在嚴重灼傷部位或傷口上，以防止體液流失及病菌入侵。

% yield =百分產率=----- x 100% = 91.8% 2007PI#8 Benzoin安息香 (a)(b)(c)(d) Part 08_p.19 14.6 g of benzoin(安息香) was obtained by heating 15.9 g of benzaldehyde with potassium cyanide in a solvent-free condition. 在不使用溶劑的條件下，把15.9 g苯甲醛與氧化餌共熱，得到14.6 g安息香。 benzoin (m.p.137°C) Calculate the percentage yield of benzoin from benzaldehyde 計算從苯甲醛生成安息香的百分產率。. (2 marks) (b) What is the function of potassium cyanide in this conversion? 在這轉化中，氰化鉀的功能是什麼? (1 mark) (c) Is this conversion an example of green chemistry? Explain. 這轉化是否綠色化學的例子?請解釋。 (1 mark) % yield =百分產率=----- x 100% = 91.8% 1 + 1

2007PI#8 Benzoin安息香 (a)(b)(c)(d) Part 08_p.19 (b) What is the function of potassium cyanide in this conversion? 在這轉化中，氰化鉀的功能是什麼? (1 mark) catalyst催化劑 1 (c) Is this conversion an example of green chemistry? Explain. 這轉化是否綠色化學的例子?請解釋。 (1 mark) Open-ended question開放式問題: Yes. Any ONE of the following: 是。可接受答以下任何一項 : -The reaction does not involve the use of solvents. 該反應並不涉及使用溶劑。 -The reaction has a high atom economy. 該反應的原子經濟性高。 -A catalyst is used.使用催化劑。 No. The reaction requires the use of KCN which is highly toxic.否。該反應需使用劇毒的KCN。

1 1 2007PI#8 Benzoin安息香 (a)(b)(c)(d) Part 08_p.19 (d) Devise an experimental procedure to remove potassium cyanide from the crude product.設計從粗產物清除氰化鉀的實驗步驟。 (2 分) 使用合適的有機溶劑，例如乙氧基乙烷，來提取安息香。 Extract benzoin with an appropriate organic solvent. such as ethoxyethane. 用水沖洗有機液層，以去掉KCN。 Wash the organic layer with water to remove KCN. 1 1

以下任何三項Any THREE of the following: : 3 2007PI#8 Benzoin安息香 (e) Part 08_p.19 (e) 利用重結晶法，可提純所得到的安息香。提出適用於這重結晶法的溶劑須具備的三項條件。 The benzoin obtained can be purified by recrystallisation. Suggest three criteria for an appropriate solvent for the recrystallisation. (3 分) 以下任何三項Any THREE of the following: : 3 - 安息香在溶劑中應有高的溶解度，但雜質則否。 benzoin should have a high solubility in the solvent while the impurities should not - 在高溫時，安息香在溶劑中應有高的溶解度;但在室溫時，溶解度則低。 the solubility of benzoin in the solvent should be high at elevated temperature but low at room temperature - 所用溶劑必須容易揮發。 the solvent should be volatile - 溶劑與安息香不起反應。 the solvent should not react with benzoin

No. CN- reacts with H+ to give toxic HCN. 2007PI#8 Benzoin安息香 (f) Part 08_p.19 ( (f) Cyanide waste is usually treated with oxidising agents. Explain whether acidified KMnO4(aq) is suitable for such a purpose.氧化劑常用來處理氰化物廢物。解釋酸化KMnO4(aq)作此用途是否恰當。 (1分) 否。CN-與H+反應產生有毒的HCN。 No. CN- reacts with H+ to give toxic HCN. HCN CN- + H+

2008PII#8(b) Polymer on breast augmentation(隆胸) Part 08_p25 Propenamide, the monomer of polypropenamide (also known as polyacrylamide), is a potential carcinogen. The melting point of propenamide is 84°C and its solubility in water is 2.16 g cm-3 at 30°C. 聚丙烯酰胺的單體是丙烯酰胺，它是潛在的致癌物。丙烯酰胺的熔點是84°C；在30°C時，它在水中的溶解度是2.16gcm-3。 (i) Polyacrylamide gel (PAAG) is polyacrylamide saturated with water. A sample of PAAG for breast augmentation (隆胸)is suspected to contain about 1 % of propenamide. Suggest a chemical test to show the presence of propenamide in the sample. expected results. 聚丙烯酰胺水凝膠(PAAG)是飽和了水的聚丙烯酰胺。一個作隆胸用的 PAAG樣本被懷疑含有約1%丙烯酰胺。建議一個化學試驗來顯示該 樣本中含有丙烯酰胺。

Add Br2/H2O or Br2/CCl4 加入 Br2/H2O 或 Br2/CCl4 1 2008PII#8(b) Polymer on breast augmentation(隆胸) Part 08_p25 (b) (i) Add Br2/H2O or Br2/CCl4 加入 Br2/H2O 或 Br2/CCl4 1 The presence of propenamide causes the reddish brown reagent to turn colourless. 丙烴酰胺令紅棕色的試劑轉為無色。

2008PII#8(b) Polymer on breast augmentation(隆胸) Part 08_p25 (5 分) (ii) 鑑定聚丙烯酰可藉著把它轉化成固體衍生物，並量度衍生物的熔點。以一條反應式為輔助，提出一個適合作此用途的丙烯酰胺固體衍生物。 Propenamide can be identified by converting it to a solid derivative and determining the melting point of the derivative. With the help of a chemical equation, suggest ONE solid derivative of prop en amide suitable for this purpose. (iii) 建議一個儀器方法可進一步顯示你在(ii)中所提出的衍生物的特徵, 並清楚寫出預期的結果。 Suggest an instrumental method for the further characterisation of the derivative suggested in (ii). State clearly the expected results.

Br2 + CH2=CHCONH2  CH2BrCHBrCONH2 1 2008PII#8(b) Polymer on breast augmentation(隆胸) Part 08_p25 (ii) Br2 + CH2=CHCONH2  CH2BrCHBrCONH2 1 (iii) Mass spectrometry質譜法 Expected results: There are three peaks for the molecular-ion at m/z = 229, 231 and 233 respectively.預期結果:分子離子引致在m/z = 229， 231及233等處分別呈現三個峰。

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www.webelements.com Nitrogen oxide 氮的氧化物 Lewis Structure 路易斯結構                 NO` NO2 N2O N2O3 N2O4 N2O5 Lewis Structure 路易斯結構 Oxidation state (氧化態/數)

http://greenchem.uoregon.edu/Pages/GreenChemGlossary.php "The Twelve Principles of Green Chemistry"* 1. Prevent Waste The ability of chemists to redesign chemical transformations to minimize the generation of hazardous waste is an important first step in pollution prevention.  By preventing waste generation, we minimize hazards associated with waste storage, transportation and treatment. 2. Maximize Atom Economy Atom Economy is a concept, developed by Barry Trost of Stanford University that evaluates the efficiency of a chemical transformation.  Similar to a yield calculation, atom economy is a ratio of the total mass of atoms in the desired product to the total mass of atoms in the reactants.  One way to minimize waste is to design chemical transformations that maximize the incorporation of all materials used in the process into the final product, resulting in few if any wasted atoms. Choosing transformations that incorporate most of the starting materials into the product is more efficient and minimizes waste. 3. Design less Hazardous Chemical Synthesis Wherever practicable, synthetic methodologies should be designed to use and generate substances that possess little or no toxicity to human health and the environment. The goal is to use less hazardous reagents whenever possible and design processes that do not produce hazardous by-products.  Often a range of reagent choices exist for a particular transformation.  This principle focuses on choosing reagents that pose the least risk and generate only benign by-products.

4. Design Safer Chemicals and Products Chemical products should be designed to affect their desired function while minimizing their toxicity.  Toxicity and ecotoxicity are properties of the product.  New products can be designed that are inherently safer, while highly effective for the target application.  In academic labs this principle should influence the design of synthetic targets and new products. 5. Use Safer Solvents/Reaction Conditions The use of auxiliary substances (e.g., solvents, separation agents, etc.) should be made unnecessary wherever possible and innocuous when used.  Solvent use leads to considerable waste.  Reduction of solvent volume or complete elimination of the solvent is often possible.  In cases where the solvent is needed, less hazardous replacements should be employed.  Purification steps also generate large sums of solvent and other waste (chromatography supports, e.g.).  Avoid purifications when possible and minimize the use of auxiliary substances when they are needed. 6. Increase Energy Efficiency Energy requirements of chemical processes should be recognized for their environmental and economic impacts and should be minimized. If possible, synthetic and purification methods should be designed for ambient temperature and pressure, so that energy costs associated with extremes in temperature and pressure are minimized.

7. Use Renewable Feedstocks Whenever possible, chemical transformations should be designed to utilize raw materials and feedstocks that are renewable.  Examples of renewable feedstocks include agricultural products or the wastes of other processes.  Examples of depleting feedstocks include raw materials that are mined or generated from fossil fuels (petroleum, natural gas or coal). 8. Avoid Chemical Derivatives Unnecessary derivatization (use of blocking groups, protection/ deprotection, temporary modification of physical/chemical processes) should be minimized or avoided if possible, because such steps require additional reagents and can generate waste.  Synthetic transformations that are more selective will eliminate or reduce the need for protecting groups.  In addition, alternative synthetic sequences may eliminate the need to transform functional groups in the presence of other sensitive functionality. 9. Use Catalysts Catalytic reagents (as selective as possible) are superior to stoichiometric reagents.  Catalysts can serve several roles during a transformation.  They can enhance the selectivity of a reaction, reduce the temperature of a transformation, enhance the extent of conversion to products and reduce reagent-based waste (since they are not consumed during the reaction).  By reducing the temperature, one can save energy and potentially avoid unwanted side reactions.  

10. Design for Degradation Chemical products should be designed so that at the end of their function they break down into innocuous degradation products and do not persist in the environment.  Efforts related to this principle focus on using molecular-level design to develop products that will degrade into hazardless substances when they are released into the environment. 11. Analyze in Real-Time to Prevent Pollution It is always important to monitor the progress of a reaction to know when the reaction is complete or to detect the emergence of any unwanted by-products.  Whenever possible, analytical methodologies should be developed and used to allow for real-time, in-process monitoring and control to minimize the formation of hazardous substances.   12. Minimize the Potential for Accidents One way to minimize the potential for chemical accidents is to choose reagents and solvents that minimize the potential for explosions, fires and accidental release.  Risks associated with these types of accidents can sometimes be reduced by altering the form (solid, liquid or gas) or composition of the reagents. * Modified from Anastas, P. T.; Warner, J. C. Green Chemistry: Theory and Practice; Oxford University Press: New York, 1998; pp 30.