1、1Chapter 5 Techniques in Green Chemistry5.1 The performance of Catalysts in Chemical reaction5.2 Green Chemistry and Catalysis5.3 The Design of High Efficient and Safe Catalyst5.4 Changing Starting Material for Chemical reaction5.5 Changing Reagents5.6 Changing the solvent of Chemical Reaction5.7 Pr

2、ocess Control and Process IntensificationReferences 25.1 The performance of Catalysts in Chemical reaction3Samples for the Application of CatalystsNoreactantsproductscatalystT/Kp/MPaphaseThe role of catalyst11/2N23/2H2NH3Fe-K2O/Al2O372340.53Gas-solidAccelerate reaction rate2aC2H41/2O2CH3CHOPdCl2-V c

3、omplex5400.1013liquidControl the Selectivity for different products42bC2H41/2O2C2 H4OAg/Al2O35200.1013 gas-solid2cC2H43O22CO22H2ONi5200.1013Gas-solid3anC3H6C3H6nO2420450202.6gas3bnC3H6C3H6nCr2O3SiO2Al2O3 or MO3Al2O3 4204503.1Gas-solid -liquid3cnC3H6C3H6nZiegler- Natta 3730.1013Gas-solid -liquid42-(6

4、-甲氧基-2萘基)丙烯酸氫左旋二羥基苯丙氨酸(L-naproxen)RuGas-solid -liquidControl the Selectivity for different productsControl the Selectivity for different products55aCH3CH2OHC2H4H2OAl2O3623683Gas,solidControl the Selectivity for different products5bCH3CH2OH（C2H5）2OH2OAl2O3523Gas,solid6aCH4O2COH2Ni/Al2O367312730.10131

5、05h1) Gas,solidControl the Selectivity for different products6bCH4O2CO2H2ONi/Al2O36730.1013氣體時(shí)空速率1000h1Gas,solid6Catalyst has been called as molecular machine Accelerate the chemical reaction rate.Accelerate selectively one of the several thermodynamically possible reactions and yield selectively th

6、e special products. Namely, the use of catalysts can control the selectivity for special products. Control the enantioselectivity of reaction. 7Catalyst has been called as molecular machine High selectivity and atom economy is of the most importance in bio-process, and all the reactions in organism

7、are catalyzed by enzyme which are characterized with high specificities, selectivity and atom economy.Synthesize the special conformation of chiral isomers: The consideration of incorporating the catalyst with the reaction conditions could control the selectivity of chemical reaction.8Catalyst has b

8、een called as molecular machine Hence, those enzyme have been called as Molecular Machine.ADPATPATPADPADPATPADP+PiATPADPA hand-over-hand mechanism for kinesin9Catalyst has been called as molecular machine Recent investigations have reported that not only enzyme acts as molecular machine but also the

9、 common catalysts own the similar functions.The classical example is the metal cyclopentadiene (環(huán)戊二烯) complex which was used as the catalyst in olefin polymerization.10continueZiegler-Natta catalyst: mechnsim? 齊格勒納塔催化劑：烷基鋁和三氯化鈦的固體混合物1112Catalyst has been called as molecular machine Enzyme and other

10、traditional chemical catalyst,If they exhibit high specificity, selectivity, yield and atom economy, they should be considered as the molecular machine with special functions in chemical reactions.135.1 The performance of Catalysts in Chemical reaction5.2 Green Chemistry and Catalysis5.3 The Design

11、of High Efficient and Safe Catalyst5.4 Changing Starting Material for Chemical reaction5.5 Changing Reagents5.6 Changing the solvent of Chemical Reaction5.7 Process Control and Process IntensificationChapter 5 Techniques in Green Chemistry145.2 Green Chemistry and Catalysis15Catalysis and Pollution

12、ProtectionThe activation of new starting materials Catalysis and Process Promotion 161、Catalysis and Pollution Protection17Catalysis plays an important role in pollution protectionCatalysis can decrease and eliminate the release of NOx in exhaust from cars and factories，and improve the air quality.H

13、igh Temperature, NOX.Load catalystLower Temperature18 Catalysis can decrease the usages of volatile organic solvents. Catalysis can substitute the synthetic methods and process composed of chlorine materials and intermediates, and decrease the formation of wastes.Catalysis plays an important role in

14、 pollution protection19 Catalysis plays an important role in newly synthesize route without pollution The chemical reaction may become more effective and more selective over catalyst, which can decrease the formation of by-products and other wastes. Catalysts can improve the reaction conditions, suc

15、h as temperature, pressure and energy consuming, and eliminate the usage of toxic reaction medium. In short, the utilization of catalyst can satisfy the requirements of Green Chemistry.202、The activation of new starting materials 21The synthesis of catechol (鄰苯二酚)Traditionally: Benzene is harmful，To

16、o many steps，By-products (ketene hydroquinone)，SO2 is not safe chemicals,continue22 Draths & Frost glucose as starting martialAvoid the usage of toxic and harmful chemicals and sharply decrease the yield of by-products. 23Conversion of BiomassBamboosSmall MoleculesSuch as: CH3COOH, CH3OH etc.New Cat

17、alysts243. Catalysis and Process Promotion25CH2=CH2O2PdCl2CuCl2水溶液 CH3CHO Disadvantages:Consume large amount of catalysts.The concentration of Cl- is greater, and can lead to the formation of chromate by-products.Those by-products is harmful to human healthy.(1) The synthesis of acetic aldehyde The

18、use of Vanadium complexes led to the decreased use of PdCl2 and the decrease of aqueous Cl-, which further resulted in the reduction of the formation of Cl-containing organic compounds.26(2) The synthesis of hydroquinoneTraditional Method：Disadvantage: too many steps, a large mount of by-product, co

19、rrosive chemicals (H2SO4,HCl)27Environmental beigen method: Advantages:Greener method:Short reaction chain，By-products only formatted in the final step.28R1C(OH)R2R1COR2Cat.MicrowaveVarma et al: the activation under microwave and catalyst without any solventTraditionallyOrganic solvent;CrO3, KMnO4;S

20、alt pollution(3) The synthesis of carbonyl compounds295.1 The performance of Catalysts in Chemical reaction5.2 Green Chemistry and Catalysis5.3 The Design of High Efficient and Safe Catalyst5.4 Changing Starting Material for Chemical reaction5.5 Changing Reagents5.6 Changing the solvent of Chemical

21、Reaction5.7 Process Control and Process IntensificationChapter 5 Techniques in Green Chemistry30 5.3 The Design of High Efficient and Safe Catalyst311: Gross analysis 1. At first, analyses: the possibility of reaction and the largest equilibrium yield, the optimized reaction conditions, the availabl

22、e materials, atom economy of reaction in real reaction , economy of catalysts, economy of catalytic reactions,in order to evaluate the reliability of real catalysts.322. Several factors should be considered to design parameters of catalysts. activity, selectivity, stability, duration and toxicity, e

23、tc.3. According to the reaction routes, search the catalyst and possible starting materials, choose the most favorable catalysts, modify and optimize the reaction conditions.4. Confirm the reaction possibility experimentally.If the experiments do not confirm the theoretical perdition, the process sh

24、ould be re-designed.1: Gross analysis 332: Design and develop the new type molecule oxygen oxidative catalystsTraditional inorganic oxidants：NaClO, NaBrO, HNO3, KHSO3,CrO3,KMnO4, KCr2O7 ,etc.The traditional inorganic oxidant can result in a large amount of: waste salts, hazardous gases and liquidshe

25、avy atoms34Clean oxidative and their characters O2:The cleanest oxidative chemicalThe limitation of its reaction conditions, Often companied by other auxiliary oxidants/reductants35H2O2H2O2 contain more than 47 percent active oxygen, and its oxidative products (water) is environmental benign chemica

26、l.H2O2 is more expensive than O2 and O3, and can decompose at room temperature. Clean oxidative and their characters36 O3：O3 is also the environmental benign chemical oxidative, and its oxidative products is oxygen molecule. But the usage of O3 often require some special method and equipments.O3 tub

27、etransformer Clean oxidative and their characters37Clean oxidative and their characters38 N2Oits oxidative products is environmental benign product (N2)the synthesis of N2O is complex and the cost of N2O is very high. Clean oxidative and their characters39 Lattice oxygenIn the metal oxides catalysts

28、 Clean oxidative and their characters40Design of oxidative catalyst based on the reaction mechanismThe reaction mechanism of different reaction system, including catalysts，may vary. Hence, the requirements for catalysts should also be different.The design of catalysts should be toughly considered th

29、e reaction mechanism to meet the requirement of reaction. 41Metal complexes Those metal-organics catalysts are widely used in homogenous catalytic reactions. Chiral metal complexes have been used as homogenous catalyst，and can control the stereo-selectivity of the reaction. It is very important for

30、high stereo-selectivity to search the suitable reaction conditions, proper central metal ions and chiral groups.3: The design of new-type metal complex catalysts42Sample：synthesis of NaproxenThe yield of target product (S-Naproxen) reaches 97%。 2,2-二（二苯基膦）-1,1-二萘的過渡金屬配合物催化劑43Table 5-2 Some metal com

31、plexes in industryChiral complesxIndoctrinationtimeRuBINAPAmine hydrogenation 1991RuBINAPchinoiline1987（Isoquinol alkaloid）RuBINAPTerpene alcohol hydrogenation 1987RuBINAPKetene hydrogenation 1911Cu Sthiff base Complexes1985（Cyclopropanation of olefins）RhBINAPhexahydrothymol1990444: Designing of New

32、 Molecular Sieve Catalyst Molecular Sieve (分子篩)Molecular sieve refers to a kind of inorganic polymer composed of aluminum silicate (silicon aluminate), bearing open structure.45Structurally, molecular sieve bears the tetra-XO4 structure.Designing of New Molecular Sieve Catalyst one atom X shares O w

33、ith other X atoms. X may be tri-(Al, B, or Ga), tetra (Ge, Si)-, or penta-(P) valent.46Designing of New Molecular Sieve Catalyst The pore diameter of molecular sieve is dependant on the number of building units, and the molecular sieve is generally named macro-, meso-, or micro-molecular sieve corre

34、sponded respectively to the mean pore diameter of 50, 2-50 or 2 nm.47Natural Molecular Sieve（Zeolite）is widely used in petrol refinery for its macrospore structure.Synthesized zeolite is now commercialized and has become one of the most important catalyst in petrol industry.XDesigning of New Molecul

35、ar Sieve Catalyst 48Separation oxygen from air變壓吸附制氧4950碳分子篩ZMS51Designing of New Molecular Sieve Catalyst Natural Molecular Sieve（Zeolite) often owns acid and base sites stimulatously.In catalysis, molecular sieve is widely used as a new acid-base catalyst in the related reactions such as the conve

36、rsion of alkanes.Natural Molecular Sieve（Zeolite）is also used in ion exchange process.52The alkylation of butene：Traditional method： HF and/or H2SO4 are used as the catalysts.Advantage: high efficiencyDisadvantages: erosion of HF/H2SO4production of inorganic saltsHF could be recycled, but H2SO4 coul

37、d not and should be removed.53Solid acid catalystthe use of solid molecular sieve acid catalyst：The erosion of liquid acid is eliminated，No inorganic salts as wastes produced.54Molecular Sieve could also be used as basic catalysts or acidic-basic bifunctional catalystAlready used for the production

38、of fundamental chemicals but not as widely as acid catalysts.It will undoubtedly play an important role in the production of fine chemicals and special chemicals. For example, Cs Molecular sieve is used in the synthesis of 4-methyl-thiazoline(4-甲基噻啉，one kind of anti-fungus) instead of Cl2 or CS2 and

39、 NaOH. 55Another example is Surface Pocket Micro-reactor. MoMCM-22 molecular sieve is developed in the synthesis of benzene form methane.Molecular Sieve could also be used as basic catalysts or acidic-basic bifunctional catalyst5657 O O OCH2 = CHCNH2 + CH2 = CHCNHCH2NHCCH = CH2(Acr)(Bis)（聚丙烯酰胺）58Cha

40、nging the selectivity of a chemical reaction originated from the shape of molecular sieve by chemical modification of molecular sieveThe selectivity of chemical reactions based on the shape of the molecular sieve could be altered by chemical modification of the molecular sieve, this provides wide ap

41、plications of molecular sieve in controlling chemical reactions.59For ExampleIn the synthesis of 2,6-di-isopropyl naphthalene, a mixture of 2,6-, 2,7-, and 2,4-substituted naphthalene is obtained using ordinary methods. 2,4-di-isopropyl naphthalene+2,7-di-isopropyl naphthalene2,6-di-isopropyl naphth

42、alene60For ExampleThe traditionally used catalyst SiO2/Al2O3 has large pores, and could not distinguish 3-substituted-isopropyl naphthalene from 4-substituted-isopropyl naphthalene, and the distinguish of 2,6-di-isopropyl naphthalene from 2,7-di-isopropyl naphthalene could neither be realized.The se

43、paration of 2,6-di-isopropyl naphthalene and 2,7-di-isopropyl naphthalene by using special polymer liquid crystal is very troublesome and very expensive.61For ExampleThe use of molecular sieve with small pores could inhibit the formation of 3-, or 4-, substituted products but the formation of equiva

44、lent amount of 2,6- and 2,7-substituted products could not be avoided.The formation of 3- and 4- substituted products could be eliminated, and a ratio of 2,6- to 2,7-substituted products of 7/3 could be obtained by using Zeolite-C as the catalyst.Table 5-3 gives out the distribution of products by u

45、sing different kinds of catalysts.62Table5-3，The distribution of the products from the alkylation of naphthalene by using different kinds of catalystsCatalystPore diameter / nm2, 6-/2, 7-2,6- isomer % SiO2/Al2O36.0132L-molecular sieve0.710.822B-molecular sieve0.73137C*zeolite0.72.770ZSM-50.55Very lo

46、w activity63Prospect for the research of molecular sieve catalystsMolecular sieve catalysts may replace such substance as HF, H2SO4, etc., which are obviously dangerous to peoples health and the environment. Thus, molecular sieve catalyst is regarded as one kind of environmentally benign catalyst. S

47、imultaneously, on account of the significant increase of the activity and selectivity due to the use of molecular sieve catalyst, the research of molecular sieve catalyst will undoubtedly become one of the most prospective field in green chemistry.645.1 The performance of Catalysts in Chemical react

48、ion5.2 Green Chemistry and Catalysis5.3 The Design of High Efficient and Safe Catalyst5.4 Changing Starting Material for Chemical reaction5.5 Changing Reagents5.6 Changing the solvent of Chemical Reaction5.7 Process Control and Process IntensificationChapter 5 Techniques in Green Chemistry655.4 Chan

49、ging Starting Material for Chemical Reaction66Selection of starting materials The feedstock has great influence on the efficiency of the synthetic routes, on the environmental effects and the healthy of human beings. The hazard of feedstock must be considered by the producers, managers in the preser

50、vation and transportation, as well as the operators in the processing. For some bulk chemicals, the change of feedstock may change the market, for some substance are produced just to provide certain feedstock.671. General principles for changing starting materials Reducing hazardous properties (1).

51、Considering the hazardous properties of the starting materials themselves whether the substance itself is benign;whether it poses a hazard for human beings and for the environments; whether it poses a hazard in the form of either toxicity, accident potential, or other forms; whether it is destructiv

52、e for the ecological environment;whether it poses other un-benign properties.68(2). Using preferable sourcesCurrently, more than 90% organic starting materials are almost exclusively derived from non-renewable carbon feedstocks, such as coal or crude oil.Petrol-refinery is energy consuming. For exam

53、ple, in the U. S., the amount of energy consumed in petrol-refinery is about 15% of its energy consumption. The cost will augment for the quality of the crude oil is becoming bad.In the production of organic chemicals from oil, oxidation reactions are usually employed, and it is well known that oxid

54、ation reactions are seriously pollutant.69(2) Using preferable sourcesConsidering the use up of oil, natural gas and coal, we must reduce our dependence on these fossil resources.Agriculture resources and bio-resources are good alternative. Recent studies show that, many agriculture resources, such

55、as corn, potato, soybean, and so on could be converted to textiles or nylon. Agriculture waste, biomass containing cellulose and lignin could also be converted to chemicals.70Advantages 1. Many choices Biomass can be broken down into a huge array of structurally diverse materials, frequently stereoc

56、hemically and enantiomerically defined, giving the user a wide range of new structural features to exploit in synthesis.2. Advantages and disadvantages of biomass as a chemical feedstock71 2. Structural diversity available The structural complexity of the building blocks available from biomass is fr

57、equently higher when compared to building blocks derived from petrochemicals. This property could lead to a reduction of reaction side products, and hence, a reduction of the amount of waste material produced in chemical processes if methodology were available to incorporate this complexity into fin

58、al products.Advantages72 3. Already Oxygen containing Building blocks isolated from crude oil are not oxygenated, yet many of the final products of the chemical industry are oxidized products. There are few ways to add oxygen to hydrocarbons, and many of them require the use of toxic reagents (chrom

59、ium, lead, etc.) in stoichiometric amounts resulting in severe waste disposal problems. Biomass derived materials are often highly oxygenated.Advantages73 4. Prolong the lifetime of fossil resource Increased use of biomass would extend the lifetime of the available crude oil supplies, and then make

60、contribution to sustainable development and make sure the production of certain chemicals that could only be synthesized from oil. Advantages74 5. Zero CO2 emission The use of biomass has been suggested as a way to mitigate the buildup of greenhouse CO2 in the atmosphere. Since biomass uses CO2 for