催化剂在化学反应中的作用课件.ppt

1、1v5.1 23NoreactantsproductscatalystT/Kp/MPaphaseThe role of catalyst11/2N23/2H2NH3Fe-K2O/Al2O372340.53Gas-solidAccelerate reaction rate2aC2H41/2O2CH3CHOPdCl2-V complex5400.1013liquidC o n t r o l the Selectivity for different products42bC2H41/2O2C2 H4OAg/Al2O35200.1013 gas-solid2cC2H43O22CO22H2ONi52

2、00.1013Gas-solid3anC3H6C3H6nO2420450202.6gas3bnC3H6C3H6nCr2O3SiO2Al2O3 or MO3Al2O3 4204503.1Gas-solid-liquid3cnC3H6C3H6nZiegler-Natta 3730.1013Gas-solid-liquid42-(6-甲甲氧基氧基-2萘基萘基)丙丙烯酸烯酸氢氢左旋二左旋二羟基苯羟基苯丙氨酸丙氨酸(L-naproxen)RuGas-solid-liquidControl the Selectivity for different productsControl the Selectiv

3、ity for different products55aCH3CH2OHC2H4H2OAl2O3623683Gas,solidC o n t r o l the Selectivity f o r different products5bCH3CH2OH（C2H5）2OH2OAl2O3523Gas,solid6aCH4O2COH2Ni/Al2O367312730.1013105h1)Gas,solidC o n t r o l the Selectivity f o r different products6bCH4O2CO2H2ONi/Al2O36730.1013气体时气体时空速率空速率1

4、000h1Gas,solid6vCatalyst has been called as molecular machine 7vCatalyst has been called as molecular machine vHigh selectivity and atom economy is of the most importance in bio-process,and all the reactions in organism are catalyzed by enzyme which are characterized with high specificities,selectiv

5、ity and atom economy.8 Hence,those enzyme have been called as Molecular Machine.ADPATPATPADPADPATPADP+PiATPADPA hand-over-hand mechanism for kinesin9vCatalyst has been called as molecular machine 10Cl4TiRCH2CH2Cl4Ti CH2CH2RCl4Ti CH2CH2RH2C CH2Cl4Ti(CH2CH2)2RCl4TiCH2CH2RZiegler-Natta catalyst:mechnsi

6、m?齐格勒纳塔催化剂：烷基铝和三氯化钛的固体混合物1112vCatalyst has been called as molecular machine 13 14151617vCatalysis 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.High Temperature,NOX.Load catalystLo

7、wer 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.19 The chemical reaction may become more effective and more selective over

8、 catalyst,which can decrease the formation of by-products and other wastes.Catalysts can improve the reaction conditions,such 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 Chemi

9、stry.2021 C6H6CH3CHCH2H3PO4CH6CH5CH(CH3)21)O2/80-130 OCOC2)SO2/60-100 CH6CH5OH+CH3CH3CH3COOC70-80 70%H2O2,EDTAFe2+orc2+OHOHOHOH+Benzene is harmful，Too many steps，By-products(ketene hydroquinone)，SO2 is not safe chemicals,22Avoid the usage of toxic and harmful chemicals and sharply decrease the yield

10、 of by-products.OOHOHOHOHHOE.ColiOHOH23BamboosSmall MoleculesSuch as:CH3COOH,CH3OH etc.New Catalysts2425PdCl2CuCl2水溶液 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

11、.v(1)The synthesis of acetic aldehyde The 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：27Environmental beige

12、n method:CH3CH3CH3CH3CH3CH3CH=CH2CH()22CH()CH3O2 CO2HCO2HOHOHH+catalystAdvantages:28Varma et al:the activation under microwave and catalyst without any solvent(3)The synthesis of carbonyl compounds2930311:Gross analysis1:Gross analysis1.At first,analyses:the possibility of reaction and the largest e

13、quilibrium yield,the optimized reaction conditions,the available materials,atom economy of reaction in real reaction,economy of catalysts,economy of catalytic reactions,321:Gross analysis1:Gross analysis332:Design and develop the new type molecule 2:Design and develop the new type molecule oxygen ox

14、idative catalystsoxygen oxidative catalystsTraditional inorganic：vNaClO,NaBrO,HNO3,KHSO3,vCrO3,KMnO4,KCr2O7,etc.The traditional inorganic 34vClean oxidative and their characters35vH2O2H2O2 contain more than 47 percent active oxygen,and its oxidative products(water)is environmental benign chemical.H2

15、O2 is more expensive than O2 and O3,and can decompose at room temperature.Clean oxidative and their characters36O3 tubetransformer Clean oxidative and their characters37Clean oxidative and their characters38 Clean oxidative and their characters39 Lattice oxygenvIn the metal oxides catalysts Ni/NiONi

16、ONireoxidationaminationreactionH2H2OO2 Clean oxidative and their characters40vThe reaction mechanism of different reaction system,including catalysts，may vary.vHence,the requirements for catalysts should also be different.vThe design of catalysts should be toughly considered the reaction mechanism t

17、o meet the requirement of reaction.41vThose metal-organics catalysts are widely used in homogenous catalytic reactions.vChiral metal complexes have been used as homogenous catalyst，and can control the stereo-selectivity of the reaction.vIt is very important for high stereo-selectivity to search the

18、suitable reaction conditions,proper central metal ions and chiral groups.42OCH3MeOMeOCOOHOHCH3MeOCOOHCH3COOHCH2MeO1)CO2 Electrolysis2)H3+OChiral Complexes CatalystH2OAcid CatalystsS-Naproxen,97%Sample：synthesis of NaproxenThe yield of target product(S-Naproxen)reaches 97%。2,2-二（二苯基膦）-1,1-二萘的过渡金属配合物催

19、化剂43Table 5-2 Some metal complexes in industryChiral complesxIndoctrinationtimeRuBINAPAmine hydrogenation 1991RuBINAPchinoiline1987（Isoquinol alkaloid）RuBINAPTerpene alcohol hydrogenation 1987RuBINAPKetene hydrogenation 1911Cu Sthiff base Complexes1985（Cyclopropanation of olefins）RhBINAPhexahydrothy

20、mol199044vMolecular Sieve(分子筛)Molecular sieve refers to a kind of inorganic polymer composed of aluminum silicate(silicon aluminate),bearing open structure.45vStructurally,vmolecular sieve bears the tetra-XO4 structure.vone atom X shares O with other X atoms.vX may be tri-(Al,B,or Ga),tetra(Ge,Si)-,

21、or penta-(P)valent.46vThe 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 corresponded respectively to the mean pore diameter of 50,2-50 or 2 nm.47X48vSeparation oxygen from air变压吸附制氧4950碳分

22、子筛ZMS51vDesigning of New Molecular Sieve Catalyst vNatural Molecular Sieve（Zeolite)often owns acid and base sites stimulatously.vIn catalysis,molecular sieve is widely used as a new acid-base catalyst in the related reactions such as the conversion of alkanes.52vTraditional method：HF and/or H2SO4 ar

23、e used as the catalysts.vAdvantage:high efficiencyvDisadvantages:lerosion of HF/H2SO4lproduction of inorganic saltslHF could be recycled,but H2SO4 could not and should be removed.CH3-CH(CH3)-CH3 +CH2=CH-CH2CH3CH3-C(CH3)-CH2-CH(CH3)-CH353CH3-CH(CH3)-CH3 +CH2=CH-CH2CH3CH3-C(CH3)-CH2-CH(CH3)-CH3Solid a

24、cid catalystvthe use of solid molecular sieve acid catalyst：vThe erosion of liquid acid is eliminated，vNo inorganic salts as wastes produced.54vAlready used for the production of fundamental chemicals but not as widely as acid catalysts.vIt will undoubtedly play an important role in the production o

25、f 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 NaOH.55vAnother example is Surface Pocket Micro-reactor.vMoMCM-22 molecular sieve is developed in the synthesis of benzene fo

26、rm methane.5657OOOCH2=CHCNH2 +CH2=CHCNHCH2NHCCH=CH2(Acr)(Bis)（聚丙烯酰胺）（聚丙烯酰胺）58vThe 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 applications of molecular sieve in controlling chemical re

27、actions.59vIn 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 naphthalene2,7-di-isopropyl naphthalene2,6-di-isopropyl naphthaleneC3H6by-products60vFor Example61vFor Example62CatalystPore diameter

28、/nm2,6-/2,7-2,6-isomer%SiO2/Al2O36.0132L-molecular sieve0.710.822B-molecular sieve0.73137C*zeolite0.72.770ZSM-50.55Very low activity63vMolecular sieve catalysts may replace such substance as HF,H2SO4,etc.,which are obviously dangerous to peoples health and the environment.Thus,molecular sieve cataly

29、st is regarded as one kind of environmentally benign catalyst.vSimultaneously,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

30、chemistry.64 6566v The feedstock has great influence on the efficiency of the synthetic routes,on the environmental effects and the healthy of human beings.v The hazard of feedstock must be considered by the producers,managers in the preservation and transportation,as well as the operators in the pr

31、ocessing.v For some bulk chemicals,the change of feedstock may change the market,for some substance are produced just to provide certain feedstock.67 (1).Considering the hazardous properties of the (1).Considering the hazardous properties of the starting materials themselvesstarting materials themse

32、lves vwhether the substance itself is benign;vwhether it poses a hazard for human beings and for the environments;vwhether it poses a hazard in the form of either toxicity,accident potential,or other forms;vwhether it is destructive for the ecological environment;vwhether it poses other un-benign pr

33、operties.68vCurrently,more than 90%organic starting materials are almost exclusively derived from non-renewable carbon feedstocks,such as coal or crude oil.vPetrol-refinery is energy consuming.For example,in the U.S.,the amount of energy consumed in petrol-refinery is about 15%of its energy consumpt

34、ion.The cost will augment for the quality of the crude oil is becoming bad.vIn the production of organic chemicals from oil,oxidation reactions are usually employed,and it is well known that oxidation reactions are seriously pollutant.69vConsidering the use up of oil,natural gas and coal,we must red

35、uce our dependence on these fossil resources.vAgriculture resources and bio-resources are good alternative.Recent studies show that,many agriculture resources,such as corn,potato,soybean,and so on could be converted to textiles or nylon.Agriculture waste,biomass containing cellulose and lignin could

36、 also be converted to chemicals.70Advantages 1.Many choices Biomass can be broken down into a huge array of structurally diverse materials,frequently stereochemically and enantiomerically defined,giving the user a wide range of new structural features to exploit in synthesis.71 2.Structural diversit

37、y available The structural complexity of the building blocks available from biomass is frequently 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 ch

38、emical processes if methodology were available to incorporate this complexity into final 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 ad

39、d oxygen to hydrocarbons,and many of them require the use of toxic reagents(chromium,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 w

40、ould extend the lifetime of the available crude oil supplies,and then make contribution to sustainable development and make sure the production of certain chemicals that could only be synthesized from oil.Advantages74Advantages75 6.Security in materials A chemicals industry incorporating a significa

41、nt percentage of renewable materials is secure because the feedstock supplies are domestic,leading to a lessened dependence on international hot spots.Advantages76Biomass is a more flexible feedstock than crude oil.The formation and composition of crude oil are set by geological forces.The diversity

42、 of building blocks from biomass offers a great opportunity for the production of a range of chemicals as wide as that available from non-renewables.With the advent of genetic engineering,the tailoring of certain plants to produce high levels of specific chemicals is also possible.Advantages77L Disa

43、dvantages Disadvantages 1.Many of the reported disadvantages are related to current economic circumstances.v The petrochemical industry Huge&highly efficient!v Moreover,the petrochemical industry is well established.Much of its capital investment is paid off.The mechanisms and operation of its proce

44、sses are well understood and give single products of high purity.v The biomass industry is still developing.782.Many of the biomass sources being considered as chemical feedstocks have traditionally been used as sources of food,and the justification for diverting part of this resource to chemical pr

45、oduction has been questioned.v The issue becomes more acute when biomass is considered as a feedstock for fuel as well as chemical production.v Biomass also requires space to grow,and the environmental impact of large scale biomass plantations has been examined.DisadvantagesDisadvantages79v Traditio

46、nal sources of chemical feedstocks have been referred to as three dimensional.The presence of the third dimension allows much more feedstock to be concentrated in a smaller area.v In contrast,biomass feedstocks are two dimensional feedstocks,and require proportionally more space for the same amount

47、of material.DisadvantagesDisadvantages80 3.Biomass is necessarily seasonal.vThe crop is planted in one part of the year,and harvested in another.This leads to peaks and valleys in the supply of feedstock;yet the chemical producer planning to use biomass needs a regular day to day supply,and needs to

48、 be assured that the material used at the beginning of the year will be of the same quality as that used at the end of the year.DisadvantagesDisadvantages81 4.The wide range of compositions of biomass could be a detriment especially if new processes need to be developed for each feedstock.Moreover,t

49、he building blocks extracted from biomass are foreign to traditional chemical producers and must be demonstrated to function in a manner similar to existing building blocks without undue manipulation.DisadvantagesDisadvantages828384Many progress have been achieved in this aspect on green chemistry.F

50、or example：Using light instead of some reagents;Using recoverable catalyst as it is possible;Loading the reagents on the support to realize the reactions(using oxidative agents,reductive agents to realize the loading).High synthetic efficiency;practicable;benign to humans health and the environment8