POLYMER-SUPPORTED RHODIUM CATALYSTS FOR CARBONYLATION OF METHYL ACETATE TO ACETIC ANHYDRIDE

Two kinds of rhodium catalysts supported on cross-linked styrene-divinylben-zene copolymers containing bipyridine or o-phenylene diamine have been prepared and found to display high activity for methyl acetate carbonylation to form acetic anhydride, the activities are even higher than their homogeneous counterparts. XPS analysis was used to characterize the synthetic catalysts. The apparent activation parameters were determined to be Ea = 73. 3 KJ/mol, △H≠ = 66. 3KJ/mol, △S≠ = - 28.6eu. These parameters are very close to those in methanol carbonylation and imply to have analogous mechanism in both cases.     

DESIGN OF POLYMER—SUPPORTED CHIRAL CATALYSTS

Some structureal factors to the design of polymer-supported Chiral Catalysts are discussed.and some new appraches for designing of polymer-supported catalysts are reviewed in this paper.     

ASYMMETRIC HYDROSILYLATION CATALYZED BY POLYMER—SUPPORTED THIAZOLIDINE RHODIUM CATALYSTS

Asymmetric hydrisilylation catalyzed by polymeric thiazolidine rhodium catalysts was conducted.Almost the same optical yields have been obtained when comb-shaped polymeric ligands and their corresponding monomer complexed rhodium cataltysts were used to asymmetric hydrosilylation of acetophenone.Optical yield of chiral 1-methylbenzyl alcohol reaches as high as 71.5%.Temperature dependence of enantioselective hydrosilylation of acetophenone was discussed.     

A NOVEL COPOLYMER-BOUND CIS-DICARBONYLRHODIUM COMPLEX FOR THE CARBONYLATION OF METHANOL TO ACETIC ACID AND ACETIC ANHYDRIDE

A series of porous microspheres of linear and ethylene diacrylate (M') cross-linked copolymers of 2-vinylpyridine (V) and methyl acrylate (M) reacted with tetracarbonyldichlorodirhodium to form a series of cis-dicarbonylrhodium chelate complex (MVRh and MVM 'Rh). They are thermally stable yet very reactive in the carbonylation of methanol to acetic acid, and of methanol-acetic acid mixture to acetic acid and acetic anhydride with a selectivity of 100% under relatively mild and anhydrous conditions.     

STUDY OF CARBONYLATION OF METHANOL TO ACETIC ACID AND ACETIC ANHYDRIDE OVER A BIDENTATE POLYMER BOUND CIS-DICARBONYLRHODIUM COMPLEX AS CATALYST

Copolymer of 2-vinylpyridine and vinylacetate coordinated with dicarbonylrhodiumused as a catalyst for carbonylation of methanol to acetic acid and anhydride has beenstudied. The structural characteristics of the copolymer ligand and complex, and the in-fluences of the reaction conditions on the carbonylation catalyzed by this polymer complexhave been investigated. In comparison with small molecule catalyst of Rh complex, thebidentate copolymer coordinated complex has better thermal stability. The reactionmechanism of the carbonylation reaction is also illustrated.     

SYNTHESIS OF POLYMER—SUPPORTED PALLADIUM CATALYSTS AND THEIR CATALYTIC BEHAVIOR FOR THE SELECTIVE HYDROGENATION OF MESITYL OXIDE

Copolymer of styrene-divinylbenzene in bead from was made by suspension polymerization.After chloromethylation and amination,five kinds of polymeric amines were thus obtained.These polymers were reacted with palladium chloride,and were then reduced.The polymer-supported catalysts synthesized above were used to catalyze the selective hydrogenation of mesityl oxide under reaction conditions of 80℃ and 10kg/cm^2,using methanol as a solvent.The catalytic activity and MIBK(methyl isobutyl ketone) formation selectivity of the catalysts were examined.     

PROMOTERS IN THE CATALYST SYSTEM FOR METHANOL CARBONYLATION TO METHYL FORMATE

在一个机械搅拌式反应器中，在反应温度为６０～９０℃，压力为３～６ＭＰａ条件下试验了几种不同类型的化合物作为甲醇催化羰化合成甲酸甲酯碱金属醇碱催化剂的助催化剂。结果发现，在甲醇羰化制甲酸甲酯反应中，是助催化剂的极性而不是碱性起着重要的作用。同时证明，强极性非质子型化合物对该羰化反应具有良好的助催效果，乙腈则是一个例外。     

POLYMER—SUPPORTED SINGLE AND MIXED AMMONIUM AND PHOSPHONIUM SALTS AS CATALYSTS FOR PHASE—TRANSFER REACTIONS

In this study was to investigate,by phase-transfer catalysis,the activity of single and mixed ammonium and phosphonium salts grafted on a “gel-type“ stryene-7% divinylbenzene copolymer in the oxidation of benzyl alcohol with hydrogen peroxide.A wide variety of catalysts with different quaternary groups and different quaternary chain length substitutents were examined.The activity of single“onium“salts increases as a consequence of the association of ammonium and phosphonium salts grafted onn the same polymeric support.The activity of polymer-supported ammonium and phosphonium salts increases with the number of carbon atoms contained in the alkyl radicals of the -onium and of the functionalization degree with phosphonium groups.     

STUDIES ON THE STATE OF PALLADIUM AND HYDROGENATION ACTIVITY OF RESIN SUPPORTED PALLADIUM—TIN OXIDE CATALYSTS

Sereral Pd-SnO2/D3520 and Pd-PbO/D3520 catalysts with Pd/D3520,SnO2/D3520 and PbO/D3520 catalysts as reference were studied by means of IR and XPS.Interaction between Pd and the second metal or between metal and support was observed.Results show that there is a strong interaction between Pd and the second metal,but there is not an obvious interaction between metal and support.The active constituent is Pd.Hydrogenation activity of the catalysts is altered because of the interaction between Pd and the second metal.The activity of the catalysis for hydrogenation has relation to outer layer valence electron density of Pd.     

PREPARATION OF POLYMER—SUPPORTED RCpCpTiCl2 AND APPLICATION IN CATALYTIC ISOMERIZATION OF 1,5—HEXADIENE

Polymer-supported RCpCpTiCl2(Cp=η^5-C5H4;RCp=η^5-RC5H4)have been prepared and reduced by i-C3H7MgBr in situ，then used in catalytic isomerization of 1,5-hexadiene.The isomerization of 1,5-hexadiene leads to a mixture of cyclic and linear products.The ratio of cyclic to linear product depends on the nature of the supporter and the substituent on the cyclopentadienyl ring.The former contributes the most,for example,silica supported Cp2 TiCl2 gave cyclic-linear ratio of 99/1,while for polymer-supported Cp2TiCl2 species,linear compounds are the major products and the ratio of cyclic to linear product changes with different R groups on the cyclopentadienyl ring.     

BICENTRAL POLYMER SUPPORTED PHASE TRANSFER CATALYST POLYSTYRENE—SUPPORTED POLYETHYLENE GLYCOL AND PYRIDINIUM SALT

A bicentral polymer-supported phase transfer catalyst,polystyrene-supported polyethylene glycol and pyridinium salt(PS-Py-PEG-400),synthesized with chloromethylated polystyrene as supporter on which PEG and pyridinium salt were immobilized successively.Its catalytic activity was tested for the reaction of solid potassium acetate and benzyl bromide by GC analysis.It was found that the bicentral catalyst performed higher activity than the monocentral PS-PEG-400 and PS-Py.     

STUDY ON THE SORPTION BEHAVIOR OF N—METHYL—2—THIO—IMIDAZOLE RESIN FOR Rh（Ⅲ）AND SEPARATION OF Rh（Ⅲ）WITH COMMON METAL IONS BY USING MTIR

The sorption behavior of N-methyl-2-thio-imidazole resin(MTIR) for Rh(Ⅲ） was investigated.The optmum sorption condition of MTIR for Rh(Ⅲ）,sorption rate t1/2=84min,sorption capacity 1.37mmol Rh(Ⅲ）/g MTIR,[140.5mg Rh(Ⅲ）/g MTIR],sorption molar ratio 0.34Rh(Ⅲ）/functional group,distribution coefficient D=2.5×10^3mg·g^-1 were determined.The sorption selectivity of MTIR for Rh(Ⅲ）in the presence of common metal ions,Fe^3+,Co^2+,Ni^2+ and Cu^2+ was examined.Rh(Ⅲ） adsorbed on MTIR can be eluted quantitatively by using a mixed solution composed of 20% thio-urea-acetone:6mol HCl.dm^-3(1:1vol.) used as an eluent.Rh(Ⅲ） can be separated from the mixture of Rh(Ⅲ） and Fe^3+,Co^2+,Ni^2+,Cu^2+ by using D72 resin and MTIR successively.