Study On Synthesis Of Di(3,4-Dimethyl) Dibenzaldehyde Sorbitol (DMDBS) As Polypropylene Nucleating Agent

The nucleating agents for Polypropylene is viewpoint of research and development progress with transparent agents of Polyalkene, Polypropylene has amplitude application foreground as one of the five current resins.Di(3,4-Dimethyl)di benzaldehyde Sorbitol(DMDBS) was empoldered for the new kind of third generations among series of Sorbitol ramifications several years ago, it was a variety of advanced capability additive of the nucleating agents for Polypropylene, having a large of application. Compared with preceding two generation of products, DMDBS has resolved the problem of low heat stability, reduced haze of transparent agents of Polyalkene significantly, improved physics mechanistical properties and machining application, it has a series of good performance,such as achromaticity, insipidity,high transparency, high finish, high degree crystallinity, good rigidity of materials. In this paper, Di(3,4-Dimethyl)dibenzaldehyde Sorbitol(DMDBS) was introduced,which has prominenced characteristic with integrated properties and convenient machining process, it is important significance to transparent agents of Polyalkene.The development progress with transparent agents of Polyalkene was discussed in this thesis,new current about Di(3,4-Dimethyl)dibenzaldehyde Sorbitol(DMDBS) was described either. Compared with technics and equipment, synthesis condition and comparison of different routes for 3,4-dimethyl benzaldehyde were described in domestic and overseas, low temperature carbonylation process was adopted, Under special reactor and mild reaction conditions ,the product was prepared by carbonylate reaction of O-xylene with CO and HCl, using Lewise acid as the complexed catalyst, 1,2-Chloroethane as the solvent, according to optimal system of catalyse and technics, we make out single factor experiment and optimal trial,The influence factors on purity of final product were investigated in detial,Sush as catalyst,reaction time and temperature, The synthetic route and reaction mechanism of 3.4-dimethylbenzaldehyde were also introduced in this paper. After a series of stable experiment,the optimal conditions of synthesis were achieved, Under following conditions: O-xylene/AlCl₃/Cu₂Cl₂/1,2-CH₂ClCH₂Cl, 1:1.25:0.15:2, reaction time wascontrolled about 8 hours, temperature: from 0 to 5 °C, the single-pass-conversion can be increased from 70% to 80%. Various element were separated by rectification, content of the aimed product was mensurated by the area normalization method. This method has some merits, including abundant raw materials,mild reaction conditions,much less of the content of isomer.at the same time,solvent and unreaction materials were recycled conveniently,After refined,yield and purity of final product were quite high.DMDBS was prepared by the aldol reaction of D-sorbitol with 3,4-Dimethyl benzaldehyde, using solid acid as the catalyst, The influence factors on the yields and melting points were investigated,Such as aldehyde/sorbitol(B/S) feeding molar ratios, accelerator,catalyst,solvent and the stirring speed. The synthetic route and reaction mechanism of DMDBS were also introduced in this paper. After single factor experiment and orthogonal experiment,the optimal conditions of synthesis were achieved, Under following conditions: aldehyde/sorbitol(B/S)feeding molar ratios 2.0—2.1:1, The amount of catalyst,surfactant and solvent 4.0%, 6.5% and 580% (weight percent), the amount of accelerator on the basis of the invariable reaction temperature,reaction time 6 hours and reaction temperature 72°C. The overall yield of DMDBS was over 70%, The melting point was over 250°C.The present dissertation had conducted intensive studies with a view to developing a crystalline polypropylene having good transparency and improved odor-non-emitting properties. DMDBS was purified by recrystallization with acetone, ethanol, methanol and N,N-dimethylformamide(DMF),The optimized conditions( solvent, solvent dosage) were investgated,which effected the yield, the melting point,the apparent of DMDBS. The qualitative analysis of 3,4-Dimethyl benzaldehyde and DMDBS were carried by infrared spectrometer separately.Compared with bath method, evaporation was adoptd as a method of recycled solvent, the yield of recycled solvent was achieved to 75%, abstersion and filtration of product were reduced to some extent, quality and property of final product were not also affected.The effect of different kinds of emulsifiers on aldol reaction was researched inthis paper. A method of measuring multivariate non-homogeneous mass transfer coefficient accompanied with reaction was studied, a mathematical model was established correspondly, stepwise search method was used to get the numerical solution.A larger scale on technic of DMDBS was studied under innovation research of tradition technic, novelty technics and flow chart with cortrolled cell were empoldered, which provided technique forerunner and theorial base for mature technics of DMDBS. advanced property and quality of DMDBS product was produced with lower cost.The technic can bring abundant benefits of society and economy as growing point in the correlational fields.