Process for preparation of methacrylic acid and methacrylic acid esters

A technology of methacrylic acid ester and methacrylic acid, applied in the field of preparation of methacrylic acid, can solve the problems of not teaching the recovery of methacrylic acid, etc., and achieve the effects of good color value and high space-time yield

Inactive Publication Date: 2015-11-11
EVONIK ROEHM GMBH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, recovery of methacrylic acid from waste oil is not taught in any of these documents

Method used

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  • Process for preparation of methacrylic acid and methacrylic acid esters
  • Process for preparation of methacrylic acid and methacrylic acid esters
  • Process for preparation of methacrylic acid and methacrylic acid esters

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0238] Example 1 describes how Figure 4 part of the method shown. 82.1% by weight of MAA, 14.3% by weight of various and partially unknown high boilers (dimeric and oligomeric MAA, maleic acid, terephthalic acid, citraconic acid, polymer etc.) and 3.6% by weight of a polymerization inhibitor (mainly hydroquinone) and the first aqueous phase containing 0.6% by weight of MAA and 5.0% by weight of high boilers isolated from the first extraction unit A3 at a ratio of 1:80 The ratio of the high boiler phase to the first aqueous phase is combined in the merging unit R. The resulting concentrations in the combined phase were measured to be 1.6% by weight of MAA and 5.1% by weight of high boilers. The combined phases are extracted in a second separation unit B with n-hexane. 4.9% by weight of MAA was produced in the organic phase, compared to 3.9% by weight of MAA in the comparative case when the first aqueous phase and the high boiler phase were not combined.

Embodiment 2

[0240] In a heatable two-stage reactor for oxidation (diameter: 16 mm) comprising evaporator, salt bath and quench column, the following streams have been fed. Polyphosphoricmolybdenumic acid (composition: Mo(10)V(1)P(1)Cu(0.2)As(0.2)Ce(0.2)) was used as a catalyst. Catalyst loading in the second stage (oxidation to methacrylic acid) was 1580h -1 .

[0241] Stream 1: Methacrolein (MAL) synthesized by aldol condensation reaction with propionaldehyde and formaldehyde as reactant, which contains 0.7% by weight of DIMAL (dipolymethacrolein), 1.5% by weight of water and 0.1 % Propionaldehyde. The stream was evaporated and oxygen, nitrogen and water in a ratio of 2.6:14:7 (reference 1 part MAL) were added to this stream in successive steps.

[0242] Stream 2: MAL synthesized via gas-phase oxidation of tert-butanol has been fed as a gas to the reactor together with oxygen, nitrogen and water. The ratio of MAL to air to nitrogen to water is 1:2.6:14:7.

[0243] For the examples c...

Embodiment 2c

[0256] Example 2c) Mixture of streams 1 and 2 in a ratio (reference MAL) of 1:1:

[0257] DIMAL content: 3300ppm,

[0258] Temperature of the salt bath (for 75% conversion): 311.5°C

[0259] Selectivity to methacrylic acid: 83.8%

[0260] TPA content in quenched liquid: about 400ppm

[0261] Minor clogging in the column; downtime for cleaning required after 25 days.

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Abstract

The invention relates to a process for preparation of at least one of methacrylic acid and a methacrylic acid ester, comprising the process stepsgas phase oxidation of at least one C4 compound, quenching of the reaction phase, separation and purification of the obtained methacrylic acid and optionally esterification,wherein the C4 compound is a methacrolein comprising mixture, originatingfrom at least two different methacrolein sources, a first methacrolein source being a feed stream obtained by the heterogeneously catalysed gas phase oxidation of isobutylene or tert-butyl alcohol or isobutylaldehyde or a mixture of two or more thereof,a second methacrolein source being a feed stream obtained by the reaction of propionaldehyde with a C1 extending agent,preferably formaldehyde, and where said methacrolein can be obtained either completely from the first methacrolein source, or completely from the second methacrolein source or from any mixture of both.

Description

technical field [0001] The invention relates to a process for the production of methacrylic acid, a process for the production of methacrylate esters and a process for the treatment of an aqueous phase comprising at least one organic compound. Background technique [0002] Methacrylic acid (MAA) and methacrylates, such as methyl methacrylate (MMA) and butyl methacrylate, are used in a variety of applications. The commercial production of methacrylic acid takes place in particular by the heterogeneously catalyzed gas-phase oxidation of isobutene, tert-butanol, methacrolein or isobutyraldehyde. The gaseous reaction phase thus obtained is converted into an aqueous methacrylic acid solution by cooling and condensation, optionally separated from low boilers such as acetaldehyde, acetone, acetic acid, acrolein and methacrolein, and then introduced into a solvent extraction column , to extract and separate methacrylic acid using a suitable extractant, such as a short-chain hydroca...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C45/32C07C45/35C07C45/65C07C45/75C07C51/25C07C47/22C07C57/04B01D3/00B01J8/00
CPCC07C51/252C07C45/75C07C51/44C07C51/48Y02P20/582C07C57/04C07C47/22B01J19/245B01J2219/24
Inventor T·巴尔杜夫S·科里尔R·布格哈特
Owner EVONIK ROEHM GMBH
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