The Technology Of Carbonylation Of Multicomponent To Synthesize Acetic Anhydride And Acetic Acid

Under appropriate catalyst,methanol can directly carbonylate to acetic acid, which compared with synthetic routes of oil,regardless of the source of raw material or the economic benefit,is obviously superior than the route of oil.Among the catalysts,rhodium catalyst due to its mild reaction condition,high activity and excellent selectivity have been studied extensively.It had been succeeded in achieving industrialization.In this paper,we select rhodium catalyst system,using autoclave to carbonylation test and make a scruting into the process parameters of heterogeneous carbonylation.Also we have done exploratory studies in other factors of carbonylation. The major research results are as follows:1.Using precious metals rhodium as the main catalyst,we also add stabilizer, catalyst promoter and initiator.The Catalyst are made from varieties of excellent grade pure organic chemical raw materials through the preparation of scientific process.Catalyst appearance of dark brown solution,the density of 1.0～1.15kg/L, viscosity 0.2～0.3cp,rhodium content:200～2000ppm,methyl iodide:5～15%.2.Under the reaction temperature 190℃,the pressure 5.0 Mpa,the residence time 90 min,raw material composition(mole ratio)AcOMe:AC₂O:MeOH:AcOH:CO= 11.5∶0.5∶3∶4.5∶4,methyl iodide 15%(Wt),Catalyst 900 ppm(Wt%). carbonylation product by CO,selective of acetic anhydride is 95.4%,conversion rate of CO 97.41%,acetic anhydride product yield 92.93%;by methanol,selective of acetic anhydride 92.51%,conversion rate of methanol 96.4%,acetic anhydride yield 89.18%,the space-time yield of catalyst 38671.28g/(mol.h);by methyl acetate, selective of acetic anhydride 88.06%,conversion rate of methyl acetate 60.25 percent,acetic anhydride yield 84.24%.3.Some metal ions such as Fe,Cr,Mo,Mn,Ni under the 150 ppm play a promoting role in carbonylation reactions,but have a inhibitory action above 300ppm. polar solvent such as acetic acid,acetic anhydride,play a promoting role in the reaction rate,benzene,methyl ethyl ketone which so weakly polar or non-polar solvent have a inhibitory action on the reaction rate inhibited.4.Through orthogonal experiments,the process parameters have been optimized,among the five factors of temperature,pressure,catalyst addition methyl iodide addition,the(most influencial factor is the catalyst addition, followed by methyl iodide addition,down followed by temperature,pressure and residence time.