Study On The Ammonolvsis Process Of Formic Acid Methallyl Ester

Methallyl alcohol is an important organic chemical intermediate,and can be used in the field of the synthesis of spices and resin.In domestic,it is mainly used for the large-scale production of methyl allyl polyethenoxy ether,which is an important raw material to produce the new generation polycarboxylic acid type water-reducer.The traditional method to produce methallyl alcohol is by the method of chlorization-hydrolysis of 3-chloro-2-methylpropene,but it consumes high energy and involves many side reactions,such as etherification and esterification.Considering these shortcomings,the research developed a new method by using 3-chloro-2-methylpropene as raw materials through the reaction of esterification and ammonolysis,on the basis of the existing esterification process,the ammonolysis process was optimized by using formic acid methallyl ester as the raw material.The reaction of formic acid methallyl ester with dimethylamine was studied,and selected basic alumina as the best catalyst.The optimum conditions were determined by single-factor experiment and orthogonal experiment:the catalyst dosage is 9.5%of the formic acid methallyl ester,reaction temperatue=20?,the dropping speed of dimethylamine agueous solution=0.84g/min,agitation speed=700r/min,the molar ratio(C5H8O2:C2H7N)=1:1.85,when reacting at the optimal conditions for 40min,the conversion of formic acid methallyl ester,the yield of methallyl alcohol,the yield and the selectivity of N,N-dimethyl formamide were 99.32%,96.39%,94.22%and 94.86%,respectively.The reaction of formic acid methallyl ester with methylamine was studied,and found the reaction could be carried out without catalysts.The optimum conditions were determined by single-factor experiment and orthogonal experiment:reaction temperatue=15?,the dropping speed of methylamine agueous solution=0.45g/min,agitation speed=200r/min,the molar ratio(C5H8O2:CH3NH2)=1:1.6,when reacting at the optimal conditions for 45min,the conversion of formic acid methallyl ester,the yield of methallyl alcohol,the yield and the selectivity of N-Methylformamide were 98.97%,95.28%,93.11%and 94.07%,respectively.The reaction of formic acid methallyl ester with ammonia was studied,and selected sodium methoxide as the best catalyst.The optimum conditions were determined by single-factor experiment and orthogonal experiment:the catalyst dosage is 10.5%of the formic acid methallyl ester,reaction temperatue=15?,the dropping speed of dimethylamine agueous solution=0.63g/min,agitation speed=400r/min,the molar ratio(C5H8O2:NH3)=1:2.1,when reacting at the optimal conditions for 30min,the conversion of formic acid methallyl ester,the yield of methallyl alcohol,the yield and the selectivity of formamide methanamide were 99.38%,97.84%,92.33%and 92.91%,respectively.The reaction mechanism and reaction dynamic processes were studied,and the elementary reactions and theory dynamic equations were obtained as follows:r=-dC_G/dt=kC_AC_B~2Combining the reaction mechanism,it is inferred that the order of the actual kinetic equation of the gas-phase reactants without catalyst is bigger than 1,and explained the catalytic mechanism of basic alumina and sodium methoxide reasonably.Verified the possible catalytic function by experiments,which the results did not prove.