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Methyl methacrylate (MMA) is an essential chemical used as raw material for the production of other methacrylates and poly-MMA. There are various chemistry routes, available or not at industrial scale, to produce MMA. These routes use the same or different raw materials, and present common chemistry and processing steps. Many of these routes though...
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... aforementioned UNIQ-HOC method also includes the necessary models for calculating mixture properties, as for example the enthalpy and density. Table 1 lists the boiling points of pure components and azeotropes, as well as the composition of the binary azeotropes formed in this quaternary system. It is worth noting the almost identical boiling points of MMA and H 2 O (the products of the esterification reaction), as well as that of the binary azeotrope MAA-H 2 O. ...Context 2
... the other hand, this light-boiling azeotrope can reach the vapor phase, carried in the overhead, contaminating the distillate; and if a two-liquid phase forms after the condensation of the vapors, then MeOH would contaminate the aqueous phase, hence having MeOH losses. The boiling temperature and composition of all the three azeotropes calculated by Aspen (Table 1) are in good agreement with those reported in the literature. . Key diagrams used in developing the separation system are shown in Figure 1. ...Context 3
... aforementioned UNIQ-HOC method also includes the necessary models for calculating mixture properties, as for example the enthalpy and density. Table 1 lists the boiling points of pure components and azeotropes, as well as the composition of the binary azeotropes formed in this quaternary system. It is worth noting the almost identical boiling points of MMA and H 2 O (the products of the esterification reaction), as well as that of the binary azeotrope MAA-H 2 O. ...Context 4
... the other hand, this light-boiling azeotrope can reach the vapor phase, carried in the overhead, contaminating the distillate; and if a two-liquid phase forms after the condensation of the vapors, then MeOH would contaminate the aqueous phase, hence having MeOH losses. The boiling temperature and composition of all the three azeotropes calculated by Aspen (Table 1) are in good agreement with those reported in the literature. . Key diagrams used in developing the separation system are shown in Figure 1. ...Citations
Two Mo-Bi based catalysts were prepared with the assistance of PMMA with different sizes, and tested in selective oxidation of tert-butanol to methacrolein. The prepared catalysts, especially C-PM-6 with μm-PMMA, exhibited excellent catalytic performance. Based on the characterization results (BET, MIP, SEM, TEM, XRD, FTIR), the effects of the assistance of PMMA with different sizes were verified. Without modifying the highly active Co6Fe4Mo12Bi1.5Ox phase, the formation of over-oxidation MoO3 phase was effectively inhibited due to the decomposition of PMMA particles. Importantly, the PMMA assistance could develop hierarchical pore structures, especially mesoporous pores of 6 nm for C-PM-6 catalyst, by preventing primary particles’ agglomeration. Therefore, the mesoporous/macroporous specific surface area obviously increased and thus the abundant active sites were exposed. More importantly, in the newly-formed mesopores pores, there happened Knudsen or molecular diffusion with relatively high mass transfer coefficient, avoiding the overoxidation of target product MAL. From the perspective of reaction engineering, our finding may suggest a new way for developing ultra-high performance commercial selective oxidation catalyst.
A comprehensive solution strategy based on genetic programming (GP) was introduced into an industrial methyl methacrylate refining plant, and the downstream separation process of acetone/butanol/ethanol fermentation in the “twin tower + horizontal bottle” cycle was optimized. The effects of different membranes and operating temperatures on the process were studied. The mixed‐membrane and modified‐membrane process parameters were shown to improve the economy and environmental protection. The total annual cost was reduced by 9 % and 22.5 %, and CO 2 , SO 2 , and NO x emissions by 37.7 % and 78.7 %, respectively. The energy‐saving distillation‐membrane separation process has significant benefits in industrial production.
A new palladium/tris(4-fluorophenyl)phosphine/p-toluenesulfonic acid catalytic system was developed to synthesize methyl propionate from ethylene hydroesterification. The influence of phosphine ligands and acid promoters on catalytic activity was systematically studied. A volcano relationship between the catalytic activity and the electric effect of phosphine ligand was achieved through the characterization of ³¹P NMR of selenium phosphine compounds. An acid strength range favorable to the hydroesterification of ethylene was found by characterizing the pKa value of Brønsted acid. Then, the effect of phosphine ligand/Pd(OAc)2 ratio, p-toluenesulfonic/Pd(OAc)2 ratio, temperature, time, and pressure on this reaction were investigated. Finally, the elementary reaction-based kinetic model was developed, which indicated that nucleophilic attack of methanol on the Pd-acyl intermediate to give methyl propionate is the rate-determining step. The activation barrier of rate-determining step is 83.1 kJ·mol⁻¹.
