Method for separating two-component azeotrope or close-boiling-point mixture

A separation method and near-boiling point technology, applied in the purification/separation/stabilization of organic compounds, the preparation of organic compounds, the purification/separation of carbonates/haloformates, etc., can solve the difficulties in the separation and recovery of organic additives, Complex separation process and other issues, to avoid decomposition and some side reactions, high chemical stability, high purity effect

Inactive Publication Date: 2015-07-08
LANZHOU INST OF CHEM PHYSICS CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] In order to solve the problems existing in the prior art, such as difficulties in the separation and recovery of organic additives, volatility, stability, and limitations in other

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0021] Embodiment 1 The separation of dibutyl carbonate and butyl carbamate

[0022] The separation of dibutyl carbonate (DBC) and butyl carbamate (BC) is a near boiling point mixture (DBC boiling point is 207°C, BC boiling point is 204°C). 200ml DBC crude product (containing 10% BC, mole fraction), 100g 1-butyl-3-methylimidazolium chloride ([BMIM]Cl), put into a 1 L distillation bottle, the vacuum distillation device includes a condenser tube (ice water condensation) and receiver. The temperature was raised to 50°C, the oil pump was depressurized to 30 mm Hg, the internal standard n-octane was added to the sample, and the internal standard method was used for quantitative analysis. The rate reached 95%. When no more DBC flows out, continue to heat up to 120°C and keep the pressure at 30 mm Hg. At this time, BC starts to evaporate. The purity of the obtained product is >99.8% through qualitative analysis, and the recovery rate of BC is up to 99%.

Embodiment 2

[0023] Embodiment 2 The separation of methyl carbamate and methyl methyl carbamate

[0024] Methyl carbamate (MC) and methyl methyl carbamate (N-MMC) are near-boiling point mixtures (MC boiling point 177°C, N-MMC boiling point 167°C). 200 g MC crude product (containing N-MMC 10%, mole fraction), 75 g [BMIM]Cl, put into a 1 L distillation flask, and the vacuum distillation device includes a condenser (ice water condensation) and a receiver. Raise the temperature to 60°C, depressurize the oil pump to 30 mm Hg, add the internal standard n-octane to the sample, and quantitatively analyze the internal standard method, the selectivity of N-MMC obtained is >99%, the selectivity of MC is 99.9% through qualitative analysis, and the recovery rate of MC reaches 99%. .

Embodiment 3

[0025] Example 3 The separation of methanol and dimethyl carbonate

[0026] Methanol and dimethyl carbonate (DMC) are an azeotropic system, and its azeotropic composition is 70wt% methanol and 30wt% DMC. After five steps of separation, the purity of DMC can reach 99.8wt%. The specific implementation steps are as follows: (1) Add 100 g of the azeotrope of methanol and DMC, 380 g of [BMIM]Cl into a 2 L distillation flask, and the vacuum distillation device includes a condenser (condensation in an ice-salt bath, the temperature is between ?20 and ? 10°C) and receiver. Raise the temperature to 40°C, and depressurize the water pump to 100-125 mm Hg to obtain a total of 40 g of a DMC-enriched mixture. Samples were added to the internal standard biphenyl, and the internal standard method was used for quantitative analysis. The selectivity of the obtained DMC was 55 wt%. Methanol The selectivity of 45wt%. When no more liquid flows out, continue to heat up to 60-100°C, and keep the p...

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Abstract

The invention discloses a method for separating a two-component azeotrope or close-boiling-point mixture. According to the method, in the presence of an ionic liquid, the method for separating the azeotrope or close-boiling-point mixture composed of two components is provided, wherein one component is a compound having hydroxyl, amino or carboxyl and other functional groups, and the other compound is a carbonate dialkyl ester or nitrogen methylated alkyl carbamate and aromatic compound. The method has the advantages that the separation process can be carried out under the condition of reduced pressure distillation, rectification is not required, the separation purity is high, the ionic liquid is easy to separate, and the reusability is good.

Description

technical field [0001] The present invention relates to a separation process for two-component azeotropes or near-boiling mixtures. Background technique [0002] In many industrial fields, large quantities of solvent mixtures are accumulated due to recycling difficulties. It is necessary to separate these mixtures into pure components so that they can be reused. However, most solvent mixtures are azeotropes or mixtures that enter the boiling point, so it is difficult to separate them by ordinary rectification, a large number of theoretical plates is required, or a large reflux ratio is required, and the operating cost is far higher separate from the general system. Potential separation methods include azeotropic distillation, extractive distillation, pressure swing distillation, liquid-liquid extraction, adsorption, and membrane separation. The currently commonly used extractive distillation has limitations in the selectivity, volatility, stability and other physical prop...

Claims

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Application Information

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IPC IPC(8): C07B63/00C07C68/08C07C69/96C07C269/08C07C271/12C07C29/82C07C31/04C07C31/08
Inventor 邓友全王培学马祥元何昱德卢六斤刘世民周峰
Owner LANZHOU INST OF CHEM PHYSICS CHINESE ACAD OF SCI
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