Kinetics of water–isocyanate reaction in N,N-dimethylformamide

The uncatalyzed reaction of p-tolyl isocyanate(p-TI)with water in N,N-dimethylformamide(DMF)was investigated by high performance liquid chromatography(HPLC).The reactions were carried out at different temperatures from 293 K to 323 K,using various molar ratios of water to p-TI.DMF,as a special amide,was proved to be an efficient catalyst for water–isocyanate reaction.Under the reaction conditions in this study,substituted urea was the only final product observed.An appreciable amount of intermediate p-toluidine was detected.Concentrations of the isocyanate group as well as the amine and urea were determined as a function of time.New kinetic equations were deduced for each of the substance on the basis of a multistep mechanism,instead of a simple second order reaction as usual.Kinetic constants were calculated using the software MATLAB.Furthermore,the effects of temperature and concentrations of reactants on the reaction rate and amine content were discussed.The activation energy of each step was also determined.

Advances in DCC Process and Catalyst for Propylene Production from Heavy Oils

In the past several decades,SINOPEC has devoted continuously great efforts to the development of DCC technology,the only commercial process using heavy feeds aiming at propylene production.Recently,a series of research breakthroughs have been achieved in molecular refining.Based on the detailed analysis on the complex DCC reaction network,an innovative catalyst technology has been developed to Optimize Catalysis Kinetics (OCK in brief).The deep-cracking process can be improved with optimizing the availability of the active sites.The updated MFI and beta zeolites are used to boost the propylene selectivity.The latest generation catalyst DMMC-1 has been applied commercially.Compared with the best historical records in the past,the propylene yield upon application of the catalyst DMMC-1 increases by 2.4 m% coupled with an improved distribution of products.The DCC technology continues to assume a leading position for manufacturing propylene from heavy feedstocks.

Atom transfer radical polymerization of methyl acrylate,methyl methacrylate and styrene in the presence of trolamine as a highly effective promoter

Transition metal-mediated atom transfer radical polymerization （ATRP） is a ＂living＂Jcontrolled radical polymerization. Recently, there has been widely increasing interest in reducing the high costs of catalyst separation and post-polymerization purification in ATRP. In this work, trolamine was found to significantly enhance the catalytical performance of CuBr]N,N,N＇,N＇-tetrakis（2-pyridylmethyl） ethyle- nediamine （CuBr/TPEN） and CuBr/tris[2-（dimethylamino） ethylamine] （CuBr/MesTREN）. With the addition of 25-fold molar amount of trolamine relative to CuBr, the catalyst loadings of CuBr/TPEN and CuBr/Me6TREN were dramatically reduced from a catalyst-to-initiator ratio of 1 to 0.01 and 0.05, respectively. The polymerizations of methyl acrylate, methyl methacrylate and styrene still showed first-order kinetics in the presence of trolamine and produced poly（methyl acrylate）, poly（methyl methacrylate） and polystyrene with molecular weights close to theoretical values and low polydispersities. These results indicate that trolamine is a highly effective and versatile promoter for ATRP and is promising for potential industrial application.