Diaryl Carbonate Transesterification Catalyst Optimization
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Solution Overview
Problem
The conversion of aromatic alcohol in the transesterification process using di(C2-C4)alkyl carbonates is lower compared to dimethyl carbonate, limiting the efficiency of diaryl carbonate production.
Innovation Solution
Adjusting the catalyst concentration and residence time such that the product of catalyst concentration and residence time (P_a) is at least 1.5 times that of dimethyl carbonate (P_m) under pre-set equilibrium conditions, allowing for higher conversion of di(C2-C4)alkyl carbonates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If di(C2-C4)alkyl carbonate is used as the dialkyl carbonate, then the reaction conditions can be adjusted to improve conversion, but the inherent conversion is lower compared to dimethyl carbonate
Solution Approach 1:
The patent applies parameter changes by adjusting the product of catalyst concentration and residence time (Pa) to be at least 1.5 times that for dimethyl carbonate (Pm). This quantitative parameter adjustment compensates for the lower inherent conversion of di(C2-C4)alkyl carbonate, transforming it into a viable alternative that achieves comparable or superior conversion efficiency through controlled parameter optimization.
2Productivity
If the product of catalyst concentration and residence time (Pa) is increased to at least 1.5 times Pm, then the conversion of di(C2-C4)alkyl carbonate is significantly increased, but the process complexity increases
Solution Approach 1:
The patent employs partial or excessive action by requiring Pa to be at least 1.5 times Pm, which is an excessive parameter requirement compared to the dimethyl carbonate process. This deliberate over-specification ensures sufficient conversion of the less reactive di(C2-C4)alkyl carbonate, accepting increased catalyst concentration and/or residence time as a trade-off for achieving the desired conversion level.
3Productivity
If dimethyl carbonate is used, then higher conversion is achieved under standard conditions, but the invention aims to enable comparable conversion with di(C2-C4)alkyl carbonate
Solution Approach 1:
The patent achieves universality by developing a process that works with multiple types of dialkyl carbonates (dimethyl carbonate, diethyl carbonate, diisopropyl carbonate, etc.) through a unified parameter control approach. By establishing the Pa ≥ 1.5×Pm criterion, the process becomes adaptable to various dialkyl carbonates, allowing selection based on economic or operational considerations rather than being limited to dimethyl carbonate.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach significantly increases the conversion of aromatic alcohol, optimizing the production of diaryl carbonate by achieving higher product yields and reducing the need for reactant recycling.
Implementation Method 1
transesterification of an aromatic alcohol with a dialkyl carbonate in the presence of a transesterification catalyst
Implementation Method 2
the transesterification reaction of dialkyl carbonate and aromatic alcohol is an equilibrium reaction
Data Source
Figure 1
AI summary
The invention relates to a process for the preparation of a diaryl carbonate by transesterification of an aromatic alcohol with a dialkyl carbonate in the presence of a transesterification catalyst during a period of time [ta], in which the aryl moiety is selected from unsubstituted phenyl and mono-, di- and trisubstituted phenyl groups, in which the alkyl moiety is selected from C2 to C4 linear and branched alkyl groups, in which the catalyst concentration is designated [ca], expressed as gram catalyst per gram of aromatic alcohol and dialkyl carbonate, in which the period of time [tm] and catalyst concentration [cm] are determined to arrive at a pre-set approach to the equilibrium for the transesterification of the aromatic alcohol with dimethyl carbonate to methyl aryl carbonate and methanol, in which the product [ca]*ta is at least 1.5* [cm]*tm, under otherwise the same reaction conditions.