Study On The Synthesis Of Methylethyloxydichlorosilane

Silane coupling agent is the most widely used silicone material.By adding a silane coupling agent to the material,the inorganic material and the organic high molecular material can be firmly bonded together and effectively improve the bonding strength of composite materials,The performance plays a key role in the modification of materials and the development of new materials.In this paper,the synthesis and purification ofmethylethoxydichlorosilane which is a novel silane coupling agent were studied.Experiments were carried out to synthesize the target methylethoxydichlorosilane with absolute ethanol（purity>99.5%）and methyltrichlorosilane as raw materials under low temperature stirring.The product was then purified by atmospheric distillation and vacuum distillation,and the purity of the purified methylethoxydichlorosilane was finally up to 99.5%.In this paper,single factor test and orthogonal test were used to explore the synthesis conditions of the target.Firstly,the effects of six factors were investigated,such as the order of the dropwise addition of the raw material,the rate of the ethanol dropping,the ratio of the raw materials,the reaction temperature,the reaction time and solvent.The preliminary conclusion is that the addition of the feedstock is carried out by adding ethanol to methyltrichlorosilane,the dropping rate of ethanol was 1.15g/min,the reaction temperature was controlled at-10℃,the molar ratio of ethanol to methyltrichlorosilane was 0.8,the Retention time is 2h,Select solvent-free system,Under these experimental conditions,the yield of the target was the highest.Then a set orthogonal test of three factors and three levels were designed on the basis of single factor experiment,the influence of raw material ratio,reaction temperature and reaction time on the experimental results was also investigated.The optimum experimental conditions were as follows: the reaction temperature was-10℃,n（C₂H₅OH）: n（CH₃SiCl₃）= 0.8: 1 and the retention time was 2h,Under these experimental conditions,the highest yield of the target product reached 52.18%,the average yield was 52.03%.In the experiment,the methylethoxydichlorosilane was purified by atmospheric distillation and vacuum distillation,The distillation conditions were determined by controlling the reflux ratio.After analysis and comparison,the optimum reflux ratio was 15.At atmospheric pressure,The purity of the product is up to 99.5% and the yield was72.32%.At a pressure of 17 kPa,the yield was 86.09%.In this paper,GC-MS,infrared spectrophotometer and NMR is used to detect and analyze the structure of the product,the results show that the structure of the product is exactly the same as that of methylethoxydichlorosilane.In addition,the content of methylethoxydichlorosilane was determined by GC,and the content of the product was up to 99.5%.