Novel technique for purifying high-quality propylene glycol in production process of dimethyl carbonate

A kind of technology of dimethyl carbonate, production process

Active Publication Date: 2010-07-14
DONGYING HI TECH SPRING CHEM IND
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  • Summary
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  • Description
  • Claims
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Problems solved by technology

[0003] The purpose of the present invention is exactly for the above-mentioned defect that prior art exists, provides a kind of new process of purification of high-quality propylene glycol...

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  • Novel technique for purifying high-quality propylene glycol in production process of dimethyl carbonate
  • Novel technique for purifying high-quality propylene glycol in production process of dimethyl carbonate

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Embodiment Construction

[0042] combined with figure 1 , the present invention comprises the following steps:

[0043] 1. Reactive distillation: Reactive distillation of methanol and propylene carbonate: propylene carbonate, methanol and catalyst sodium methoxide are mixed into the static mixer through the feed pump, and the mixed materials enter the reactive distillation tower T101 . Control the mol ratio of methyl alcohol and propylene carbonate in the reactive rectification tower to be: 8~15: 1, control the content of catalyst sodium methylate on each layer tray in the reactive rectification tower at 0.20%~0.80% (mass percentage). Control the reaction temperature of the reactive distillation tower at 50°C to 100°C, the pressure at 0.060MPa to 0.20MPa, the reflux ratio at 0.30 to 2.0, and the reaction residence time at 0.35 to 1.5 hours. The azeotrope of methanol and dimethyl carbonate obtained at the top of the tower enters the extractive distillation column T102 for separation. And the still li...

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Abstract

The invention relates to a technique for coproduction of dimethyl carbonate and propylene glycol, in particular to a novel technique for purifying high-quality propylene glycol in the production process of dimethyl carbonate. The technical scheme includes the steps of reactive distillation, extractive distillation, separation of the dimethyl carbonate, the recovery and refining of carbinol, primary carbonization, first filtration of sodium carbonate crystals and refining of the propylene glycol. The invention solves the problem of low recovery rate of the propylene glycol, and the recovery rate of the propylene glycol can be above 95%. Meanwhile, the propylene glycol has more stable quality, with the purity reaching 99.99% and the chroma less than 10, thereby the propylene glycol totally meets the requirements for medical auxiliary material, daily cosmetics, top grade unsaturated resin and polyether. Meanwhile, the purity of the byproduct dipropylene glycol can be above 99.50%, thus improving the benefit of the equipment.

Description

1. Technical field: [0001] The invention relates to a co-production process of dimethyl carbonate and propylene glycol, in particular to a new process for purifying high-quality propylene glycol in the production process of dimethyl carbonate. 2. Background technology: [0002] Dimethyl carbonate (DMC) is a very important chemical raw material. At present, most domestic dimethyl carbonate production devices are produced by transesterification. The homogeneous catalyst "sodium methoxide" is used as the catalyst for transesterification. Due to the deactivation of "sodium methoxide" in the process of transesterification between propylene carbonate and methanol, the current catalyst cannot be recycled normally. Therefore, it is necessary to separate the catalyst from the bottom material of the reactive distillation column. In the original production process, most of them use high-temperature evaporation to separate propylene glycol from the catalyst sodium methoxide, and there ...

Claims

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Application Information

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IPC IPC(8): C07C31/20C07C29/74C07C69/96C07C68/06
CPCY02P20/10
Inventor 张化岚滕文彬张云烽杜桂强
Owner DONGYING HI TECH SPRING CHEM IND
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