Method for refining polyoxymethylene dimethyl ether (PODE)

A technology of dimethyl ether and polyoxymethylene, applied in chemical instruments and methods, preparation of organic compounds, organic chemistry, etc., can solve problems such as high cost, high cost, and low product yield, and achieve good economy and feasibility The effect of high stability, mild operating conditions, and simple recovery methods

Active Publication Date: 2015-04-29
CHINA PETROLEUM & CHEM CORP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

CN101182367 (US7560599) has introduced the method that methanol and trioxane are raw materials to prepare polyoxymethylene dimethyl ether, in the product: DMM accounts for 39.5%, PODE 2 Accounting for 26.3%, PODE 3-8 It accounts for 30.1%; although the raw material methanol is completely reacted, ionic liquid is used as catalyst and solvent, which is expensive and costly, and is not suitable for large-scale production; W02006 / 045506A1 introduced that BASF Company replaced methanol with methanol derivatives, and used DMM, three The method of synthesizing paraformaldehyde dimethyl ether from polyoxymethylene, using sulfuric acid and trifluoromethanesulfonic acid as catalysts, obtained a series of products with n=1~10, of which: DMM accounted for 33.5%, PODE 2 Accounting for 23.6%, the effective additive component PODE 3-8 Less than 28.3%; the raw material DMM of this process is not a bulk chemical, and PODE 2 The solvent as the unreacted material is recycled to the reactor together, which is expensive and the product yield is low, which is not conducive to industrial production

Method used

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  • Method for refining polyoxymethylene dimethyl ether (PODE)

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0030] With cyclohexane as entrainer, PODE 2 The crude product is a raw material (composed by weight: 13.84wt% methanol, 1.02wt% DMM, 84.85wt% PODE 2 and the remainder of other impurities) for azeotropic distillation. Take cyclohexane 75g respectively, PODE 2 300g of the crude product (containing 41.5g of methanol) was added to the rectification tower, heated under normal pressure, the reflux ratio was 2, the temperature of the top of the azeotropic rectification tower was 54~56°C, and the temperature of the bottom of the tower was 105°C. Light component 1 and bottom liquid 1. After the light component 1 is fully mixed with an equal amount of water, it is allowed to stand and separate into layers. The upper layer liquid is recovered entrainer cyclohexane, and the lower layer is aqueous methanol solution.

[0031] The light component 1 and the bottom liquid 1 were sampled respectively, and gas chromatography analysis was carried out after standing and cooling. The results a...

Embodiment 2

[0037] With n-hexane as entrainer, PODE 2 The crude product is a raw material (composed by weight: 13.84wt% methanol, 1.02wt% DMM, 84.85wt% PODE 2 and the remainder of other impurities) for azeotropic distillation. Take 110g of n-hexane, PODE 2 300g of the crude product (containing 41.5g of methanol) was added to the rectification tower, heated under normal pressure, the reflux ratio was 5, the temperature of the top of the azeotropic rectification tower was 50~52°C, and the temperature of the bottom of the tower was 100°C to obtain the Light component 2 and bottom liquid 2. After the light component 2 is fully mixed with an equal amount of water, it is allowed to stand and separate into layers. The upper layer liquid is recovered entrainer n-hexane, and the lower layer is aqueous methanol solution.

[0038] The light component 2 and the tower bottom liquid 2 were sampled respectively, and gas chromatographic analysis was carried out after standing and cooling. The results...

Embodiment 3

[0041] With n-heptane as entrainer, PODE 2 The crude product is a raw material (composed by weight: 13.84wt% methanol, 1.02wt% DMM, 84.85wt% PODE 2 and the remainder of other impurities) for azeotropic distillation. Take 45g of n-heptane respectively, PODE 2 300g of the crude product (containing 41.5g of methanol) was added to the rectification tower, heated under normal pressure, the reflux ratio was 8, the temperature of the top of the azeotropic rectification tower was 59~61°C, and the temperature of the bottom of the tower was 120°C. Light component 3 and bottom liquid 3. After the light component 3 is fully mixed with an equal amount of water, it is allowed to stand and separate into layers. The upper layer liquid is recovered entrainer n-heptane, and the lower layer is aqueous methanol solution.

[0042] The light component 3 and the tower bottom liquid 3 were sampled respectively, and gas chromatographic analysis was carried out after standing and cooling. The resul...

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Abstract

The invention relates to a method for refining polyoxymethylene dimethyl ether (PODE). The method is mainly used for solving the problem that the property of a PODE product is affected due to the presence of methanol. The problem of the influence of methanol on the separation of the PODE product is well solved by adopting the technical scheme of the method for refining PODE; according to the method, alkane or halogenated alkane having a boiling point of 30-100 DEG C is used as an azeotropic agent to remove methanol in the PODE crude product by virtue of azeotropic distillation; and the method comprises the following steps: adding the azeotropic agent and the crude product into an azeotropic distillation tower, carrying out azeotropic distillation to distill an azeotrope formed by methanol and the azeotropic agent out from the tower top and enabling purified PODE to flow out from the tower bottom; enabling the azeotrope obtained at the tower top to enter a solvent recovery tank and be in contact with water and naturally layering to obtain an oil layer containing the azeotropic agent and a water layer containing methanol. The method can be used in the refining production of polyoxymethylene dimethyl ether as a diesel additive.

Description

technical field [0001] The present invention relates to the method for refining polyoxymethylene dimethyl ether, especially remove polyoxymethylene dimethyl ether dimer (referred to as PODE 2 ) method of methanol in the crude product. Background technique [0002] With the sharp increase of energy consumption in modern society, the increasing shortage of petroleum resources, and the increasing pressure on the environment, it is urgent to develop new clean diesel fuels. The use of oxygen-containing compounds as diesel additives is a convenient and effective measure without adding additional devices or changing the engine structure, and has become a new idea for the development of the petroleum industry. [0003] Polyoxymethylene dimethyl ether (PODE) is an oxygen-containing compound with the general formula: CH 3 O(CH 2 O) n CH 3 , where n is an integer ≥ 1 (generally the value is less than 10, for PODE with different n, PODE is used below n express). Polyoxymethylene...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C43/30C07C41/58
CPCC07C41/58C07C43/30
Inventor 裴义霞顾军民吕国强韩诚康
Owner CHINA PETROLEUM & CHEM CORP
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