Transesterification Of Methyl Acetate Research Articles

Transesterification of Methyl Acetate Using a Flow-Type Membrane Reactor with a Zeolite Membrane

Transesterification of Methyl Acetate Using a Flow-Type Membrane Reactor with a Zeolite Membrane

Co-process intensification in the synthesis and design of reactive double dividing-wall distillation columns

In most cases, the reactive single dividing-wall distillation column (R-SDWDC) and its corresponding conventional reactive distillation system (CRDS) fail to yield the best performance in the separations of reacting mixtures with unfavorable reaction kinetics and/or unfavorable thermodynamics properties. In this work, a novel methodology of co-process intensification is proposed for the synthesis and design of reactive dividing-wall distillation columns. The methodology leads to the establishment of a reactive double dividing-wall distillation column (R-DDWDC), and the included intermediate separating section plays a vital role in coordinating these two kinds of process intensification and consequently guarantees its optimum performance. In terms of two example systems involving the separations of the ideal quaternary reversible reaction with a somewhat unfavorable ranking of relative volatilities (A + B ↔ C + D with αA > αC > αB > αD) and the transesterification of methyl acetate with n-propanol, the proposed methodology is evaluated. The R-DDWDC is found to yield much better performance than the CRDS and R-SDWDC in the separations of the reacting mixtures with somewhat unfavorable ranking of relative volatilities, and such outcomes definitely corroborate the effectiveness and advantages of the proposed methodology for process development. Although the proposed methodology is developed solely based on the separations of the reacting mixtures with somewhat unfavorable ranking of relative volatilities, it is of great implication to the separations of the other reacting mixtures with unfavorable reaction kinetics and/or unfavorable thermodynamics properties.

Exergy, economic and environmental analysis of an integrated pressure-swing reactive distillation process for the isobutyl acetate production via methyl acetate transesterification

As a greener bio-based solvent, isobutyl acetate (ISBAC) was widely applied in biorefineries around value-added production for environmental protection and ecological safety. The convention production of ISBAC, which was obtained by the reaction of alcohols and acids, can form by-product water to cause the multiple heterogeneous azeotropes and further enormously increase separation difficulty and production costs. This work adopted the transesterification of methyl acetate (MeAC) from the by-product (typical compositions MM20 (15.64 mol% MeAc, 84.36 mol% MeOH) and MM80 (65 mol% MeAC, 35 mol% MeOH) of polyvinyl alcohol (PVA) manufacture and isobutanol (ISBOH) to product ISBAC to avoid the multiple heterogeneous azeotropes. The ISBAC production by MeAC in MM20 and MM80 reacted with ISBOH adopted reactive distillation (RD) combining pressure-swing to break the limits of chemical equilibrium and azeotrope separation. Furthermore, heat integration, thermal coupling, and heat pump technologies were used to systematically recover waste heat and achieve energy-saving for ISBAC production processes. The exergy, economy, and environment evaluation displayed that the heat integration of MM20 pressure-swing RD was the best attractive process by reducing 19.35% total annual cost (TAC), 34.58% CO2 emissions, and improving 33.16% thermodynamic efficiency. The heat source of the low-pressure column and preheating process feed using top steam of the high-pressure column（heat integration-F） of MM80 pressure-swing RD process was the most promising process due to the decrease of 5.40% in TAC, 16.70% in CO2 emissions and obtained the improvement of 4.50% thermodynamic efficiency comparing with the conventional process.

Highly basic solid catalysts obtained by spray drying of a NaAlO2 and boehmite suspension for the upgrading of glycerol to acetins

In here, we present the low-cost spray drying production of NaAlO2–Al2O3 catalysts, which exhibit high activity in the transesterification of methyl acetate with glycerol to obtain acetins.

Pressure selection for non-reactive and reactive pressure-swing distillation

Pressure-swing distillation is the only enhanced distillation technique that does not rely on using an agent to promote the separation of azeotropes. This technology exploits the variation of the azeotropic composition or the disappearance of the azeotrope itself with pressure. A heuristic based on the azeotrope pressure-sensitiveness is commonly considered to evaluate the process feasibility. However, column operating pressures are chosen rather arbitrarily. Therefore, the operating pressure selection is addressed in the present study. When the reboilers and condenser duties are provided by the services available, the temperatures of the cooling and heating services available should be considered to adjust the columns pressures. The low-pressure distillate temperature must be the suitable to be cooled with refrigeration water and the high-pressure bottoms temperature must be the suitable to be heated with the available steam hot services; these boiling point temperatures depend on the column pressure. However, an analysis of the literature available shows that the low pressure is usually fixed at atmospheric pressure for sake of simplicity and the different steam qualities costs are disregarded. Two case studies are presented for illustrative purpose: binary mixture ethanol/ethyl acetate and methyl acetate transesterification with isobutanol as example of reactive pressure swing distillation.

A hybrid reactive distillation process with high selectivity pervaporation for butyl acetate production via transesterification

A hybrid reactive distillation system with high selectivity pervaporation was examined to produce butyl acetate and methanol via transesterification of methyl acetate with butanol. High selectivity pervaporation was combined with reactive distillation to eliminate a hitherto required column for the separation of a methanol and methyl acetate azeotrope. The polyamide-6 membrane was used for this purpose because of its high selectivity for methanol while also allowing sufficient permeate flux. The high purity methyl acetate recovered in the retentate stream leads to high conversion in the reactive distillation column, which enhances the energy savings (up to 71%) of this process. The feasibility of the proposed hybrid processes and several alternative designs were evaluated by rigorous simulation and optimization using the Aspen Plus software package. The effects of several designs and operating variables were also investigated for the proposed design. The high potential of the hybrid reactive distillation and pervaporation system for butyl acetate production is very promising; it may not only reduce the total annual costs relative to conventional systems but may also provide an attractive strategy to address problems associated with methanol and methyl acetate azeotropes in the effluent generated in the polyvinyl alcohol industry.

Transesterification of Methyl Acetate with n-Butanol Catalyzed by Single and Mixed Ionic Liquids

Several acidic ionic liquids (ILs) with different cations and anions were used as catalysts in the transesterification of methyl acetate with n-butanol. The IL [omim][PF6] can enhance the catalytic activity of the partially soluble IL catalyst. The kinetics for the transesterification using the catalysts [HSO3bmim][p-TS] and [HSO3bmim][OTF] were measured. The ideal homogeneous model and the nonideal homogeneous (NIH) model were used to correlate the kinetic data. The NIH model was more reliable to describe the reaction rate.

Synthesis of 2-Ethylhexyl Acetate by Transesterification of Methyl Acetate with 2-Ethylhexanol

Synthesis of 2-Ethylhexyl Acetate by Transesterification of Methyl Acetate with 2-Ethylhexanol

Control of plantwide reactive distillation processes: Hydrolysis, transesterification and two-stage esterification

General design principles for controlling plantwide reactive distillation processes are developed in this work. Three cases of plantwide RD processes with large recycle flow rates are used to illustrate the application of the design principals. The cases are hydrolysis of methyl acetate, transesterification of methyl acetate and esterification of adipic acid. The design principles produce workable control structures for the three systems. Temperature and temperature-composition control structures can deal with the two major disturbances: changes in the feed flow rates and reactant composition. Results show that the control structures offer good robustness and acceptable dynamic performances.

Experimental study and process simulation of n-butyl acetate produced by transesterification in a catalytic distillation column

The production of n-butyl acetate by transesterification of methyl acetate with n-butanol, catalyzed by acidic ion-exchange resin NKC-9, was experimentally investigated in a homemade catalytic distillation column with a diameter of 80 mm. A non-equilibrium stage model for describing the catalytic distillation process was established and solved with Newton-Homotopy method. The effect of feeding mode, reflux ratio, material molar ratio and number of reactive sections on the conversion of methyl acetate was investigated. The experimental results agree well with those obtained by the theoretical simulation calculations, indicating the accuracy and reliability of the non-equilibrium model. It can be concluded that the non-equilibrium model established in this paper can provide theoretical guidance for the further process design and optimization.

Control of Transesterification Distillation for the Production of Methanol and n-Butyl Acetate

The control strategy of a reactive distillation column for the production of methanol and n-butyl acetate by transesterification of methyl acetate and n-butanol is investigated. The keys of controlling the column, in which the reaction is kinetically controlled, are (1) to maintain the quality of two products, (2) to maintain the correct stoichiometric balance between the feeds, (3) to account for possible changes in control objective when throughput rate changes. Proper pairing of controlled and manipulated variables chosen for these three objectives was determined by using steady-state analysis. The top temperature is controlled by manipulating a reflux flow to maintain the top product quality. The bottom product quality is maintained by a feed ratio plus bottom temperature control scheme using a control valve installed on the n-butanol feed-line as a manipulated variable. The bottom n-butanol composition is controlled by manipulating the reboiler duty to maintain stoichiometric balance. Simulations show that such a control scheme can provide adequate control of the system, while a more intuitive scheme of controlling the bottom product quality with reboiler duty and maintaining stoichiometric balance using a reactant feed flow does not work.

Transesterification processes by combination of reactive distillation and pervaporation

The development of a reactive distillation process for the production of n-butyl acetate by transesterification of methyl acetate with n-butanol is presented. Thermodynamic aspects of the quaternary system n-butyl acetate– n-butanol–methyl acetate–methanol are discussed and UNIQUAC interaction parameters derived using the Dortmund Data Bank (DDB) are given. The reaction kinetics of the heterogeneously by a strongly acidic ion-exchange resin (Amberlyst 15) catalyzed reaction has been investigated and the kinetic constants for a pseudohomogeneous kinetic model are presented. Pervaporation experiments using Pervap 2255 membranes have been conducted for the separation of the methanol–methyl acetate binary mixture which forms the distillate stream of the reactive distillation column. Reactive distillation experiments have been performed using the structured catalytic packings Katapak-S (Sulzer Chemtech) and Katapak-SP (type SP 11, Sulzer Chemtech). Important operating conditions (reflux ratio, total feed rate) have been varied experimentally. The experimental results are presented in comparison with simulation results. An equilibrium stage model for the modeling of the distillation is capable of describing the composition profiles quantitatively. Finally, a new process, combining reactive distillation with pervaporation, has been developed and investigated by means of simulation studies. It has been shown that the combination of reactive distillation with pervaporation is favorable since conversions close to 100% can be obtained with a reasonable size of the reactive section.