绿色化学原则.ppt

綠色化學的原則,Anastas&Warner(1998)的十二條原則(化工技術,9(12),128,2001)盡量避免廢棄物的生成,從源頭防治污染 盡量使得製程中所採用的原料,進入最終產品之中 盡量使得所使用與產生的物質對人體健康和環境無毒無害 盡量使得產品具有高效的功能與最低的毒性 盡量避免使用溶劑,分離試劑等助劑,如不可避免時,也要選用無毒無害的助劑,綠色化學的原則(2),盡量降低製程的能耗,最好在溫和的溫度與壓力下進行 在技術可行和經濟合理的前提下,降量採用可再生資源代替消耗性資源 盡量避免使用與產生不必要的衍生物 盡量選用高選擇性的催化劑,這比使用化學劑量助劑更優越 改用溫和的生物製程(酵素:生物觸媒)進量使產品在其成功終結後,不會永存於環境中,要能分解成無害的物質,綠色化學的原則(3),儘量在製程中即時線上監控,有可能產生的有害物質,並儘量避免產生這些有害物質 儘量使用與產生可降低意外事故如洩漏,爆炸,火災等的化學品,綠色化學,Green Chemistry,替代性原料無毒性/低毒性,替代性溶劑H2O,新觸媒更有效率,生物程序生物觸媒,替代性產品,提升製程效率,Design Safer Chemicals,藉由分子設計概念,使用各種合成化學(organic/inorganic)得到比較安全的化學品。早期focus:efficacy of chemicals,i.e.效用好,成本低;如今修正為:必須注重對環境與與健康安全的影響與衝擊(or 毒性)Green Chemistry is a source prevention approach;new chemical structural design safe and efficacious existing chemicals(toxic)structural redesign safe and efficacious,General Approaches,Reducing absorption;Use of toxic mechanismUse of structural-activity relationshipUse of isosteric replacementUse of retrometabolic design,Identification of equally efficacious,less toxic chemical substitutesElimination of the need for associated toxic substances,ACS,640,1996,減少吸收 降低效應,毒性物質之生物化學:知其原因,才有對策影響吸收的因素:physicochemical factors molecular size,MW,dissociation constant,solubility,lipophilicity,physical state(G,L or S),particle size;細胞膜內含有lipid,所以lipid solubility 在腸胃內吸收角色重要;表面積(m2)吸收層厚度(m)血流速(L/min)皮膚 1.8 100-1000 0.5小腸 200 8-12 1.4肺部 140 0.2-0.4 5.8Designing safer chemicals,ACS 640,1996,Toxic Mechanism,Electrophilic chemical substances,Electrophilic metabolites(from metabolism),Reactions with nucleophilesWith defensive system,Reactions with nucleophilesOf non-defensive cellularMolecules,DNA,RNA,etc,excretion toxicity,Path I Path II,Structural Modifications,1-(alkoxy)-2-propanolR-O-CH2-C(CH2)-HOH,1-(alkoxy)-1-propanolR-O-CH(CH2)-CH2OH,No toxicity,Toxicity,Hexane,2,5-dimethyl hexane,Neurotoxicity,No toxicity expected;BP增加40oC,藉由改變新陳代謝路徑達成降低毒性效果,Use of Structure-Activity Relationship,近年來分子模擬的主要工作;sometimes called structure property relationship;From qualitative relationship to quantitative structure activity relationships(QSAR);後者定量關係之建立可以靠(i)correlation;or(ii)molecular simulation;用於發展藥物的技巧,Some Examples,Polyeoxylated nonylphenols:as surfactants/emulsifiers;,Glycidyl ethers:as reagents for synthesis;,Isosteric Replacements,一個新的定義:isosteres chemical substances,atoms,or substituents that possess near equal or similar molecular shape and volume,approximately the same distribution of electrons,and which exhibit similar physicochemical properties.,範例:三者皆為液體,12,Metallized azo dyes:M=Cr(toxic)M=Fe 色澤類似,但不具毒性,Other Techniques,retrometabolic design:soft drug 觀念,i.e.該物質很容易被新陳代謝作用轉換掉,e.g.hydrolysis step;因而毒性降低 Equally useful,less toxic substitutes:例如 acetoacetate 取代isocyanate in sealant and adhesive;isothiazolones for organotin as antifoulant for ships;等 Elimination of the need for associated toxic substances:該物質本身無毒,但其輸送儲存時會用到毒性物質,e.g.油漆,水性比油性好,no or less VOC;,Designing Biodegradable Chemicals,p.157-171,ACS 640,1996;Microbial degradation is the major loss mechanism for most organic chemicals;一般會增加生物分解阻力者:(a)含鹵素,esp.Cl,F;(b)太多支鏈,branched,such as quaternary C or tertiary N;(c)nitro-,nitroso-azo-arylamino groups;(d)polycyclic residues,尤其是超過三個以上;(e)aliphatic ether bonds,C-O-C;生物法合成的東西大概都可以被生物分解;,Biodegradable Chemicals(2),比較喜歡:引入oxygen in the form of hydroxyl,aldehydic,carboxylic;unsubstituted linear alkyl chains(4)and phenyl rings;,TPBS:tetrapropylene akylbenzene sulfonate;LAS:linear alkylbenzene sulfonate後者比前者容易被生物分解(一般用途:清潔劑),前:Ethoxylated ethanaminium quaternary ammonium salt後:ester analog of previous compound;比較容易為生物分解,