Method for recycling and reusing benzyl alcohol rectification by-products

A technology of benzyl alcohol and by-products, which is applied in the field of recovery and reuse of benzyl alcohol rectification by-products, can solve the problems of difficult recovery and reuse of acetal and dibenzyl ether, cannot remove trace amounts of toluene, and is not easy to separate, so as to achieve environmental protection benefits Outstanding, good economic and environmental benefits, easy separation and purification effects

Active Publication Date: 2018-11-16
WUHAN YOUJI IND
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Due to the high boiling point of the two, effective and complete separation cannot be achieved through rectification, so the recovery and reuse of acetal and dibenzyl ether are more difficult
From the perspective of economic benefits, since the by-product of benzyl alcohol rectification is a mixture of dibenzyl ether and acetal, which has a high boiling point and is not easy to separate, it can only be treated as waste with almost zero value.
[0008] Second, for the separation of trace amounts of toluene in benzyl alcohol, it has been found in many experiments that the trace amount of toluene contained in benzyl alcohol cannot be completely removed by the vacuum distillation method of rectification tower

Method used

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  • Method for recycling and reusing benzyl alcohol rectification by-products

Examples

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Effect test

Embodiment 1

[0028] A method for reclaiming and reusing benzyl alcohol rectification by-products, comprising the following steps:

[0029] 1) Add 400kg of benzyl alcohol rectification by-products in a 2000L autoclave (after testing, the mass fraction of dibenzyl ether is 37%, the mass fraction of acetal is 60%, and the others are impurities), and 800kg of ethanol with a mass fraction of 95% is added, Raney nickel (mass fraction 50%, water content) 20kg, under stirring, replace the gas in the kettle with hydrogen 3 times; heat up to 100°C, control the hydrogen pressure of the system to be 3-4MPa, the reaction exotherm is obvious, and stop after the hydrogen pressure no longer drops Reaction, about 5 hours. Stand still for 2 hours, absorb the supernatant (ie the crude product of the organic phase), and the catalyst stays in the kettle for the next reaction;

[0030] 2) The crude product of the organic phase first enters the crude distillation tower for crude distillation under reduced press...

Embodiment 2

[0035] 1) Add 400kg of by-products of benzyl alcohol rectification in a 2000L autoclave (after testing, the mass fraction containing dibenzyl ether is 32%, the mass fraction of acetal is 65%, and the others are impurities), add 800kg of ethanol with a mass fraction of 95%, Raney nickel (mass fraction 50%, containing water) 20kg, under stirring, replace the gas in the kettle with hydrogen for 3 times. Raise the temperature to 100°C, control the system pressure to 3.5 MPa, the reaction exotherm is obvious, and the reaction stops after the hydrogen pressure no longer drops, about 6 hours. Stand still for 2 hours, absorb the supernatant (ie the crude product of the organic phase), and the catalyst stays in the kettle for the next reaction;

[0036] 2) The crude product of the organic phase first enters the crude distillation tower for crude distillation under reduced pressure. The conditions for the crude distillation under reduced pressure are temperature 85°C and vacuum 45kpa to...

Embodiment 3

[0041] A method for reclaiming and reusing benzyl alcohol rectification by-products, comprising the following steps:

[0042] 1) Add 400kg of by-products of benzyl alcohol rectification in a 2000L autoclave (after testing, the mass fraction containing dibenzyl ether is 23%, the mass fraction of acetal is 75%, and the others are impurities), add 800kg of ethanol with a mass fraction of 90%, Raney nickel (mass fraction 50%, containing water) 22kg, under stirring, gas in the hydrogen replacement kettle was replaced 3 times. Raise the temperature to 110°C, control the system pressure to 3-4 MPa, the reaction exotherm is obvious, and the reaction stops after the hydrogen pressure no longer drops, about 4 hours. Stand still for 2 hours, absorb the supernatant (ie the crude product of the organic phase), and the catalyst stays in the kettle for the next reaction;

[0043] 2) The crude product of the organic phase first enters the crude distillation tower for crude distillation under...

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Abstract

The invention discloses a method for recycling and reusing benzyl alcohol rectification by-products, comprising the following steps: adding benzyl alcohol rectification by-products containing acetal and dibenzyl ether, ethanol and a hydrogenation catalyst into an autoclave, introducing hydrogen and heating to 100 DEG C, reacting for 4-8 h, and separating an organic-phase crude product; carrying out crude distillation on the crude product under reduced pressure, and removing ethanol and most toluene in the crude product; boiling with water at normal pressure, and evaporating water to remove residual trace amount of toluene; and finally carrying out vacuum distillation to obtain the finished product benzyl alcohol. Through one-step chemical conversion, recycling and reusing of dibenzyl etherand acetal which are difficult to separate are realized. Meanwhile, the products after conversion are mainly benzyl alcohol and a small amount of toluene, which are easy to separate and purify; economic value of benzyl alcohol is high; and the market demand is large. Thus, the process is suitable for large-scale production and application. By changing wastes into valuable things, making good useof waste materials and saving resources, the method has great economic and environmental benefits.

Description

technical field [0001] The invention relates to a method for recycling rectification by-products, in particular to a method for recycling benzyl alcohol rectification by-products. Background technique [0002] Benzyl alcohol is a colorless, transparent, viscous liquid with a faint aromatic smell. It is mainly used in the fields of chemical industry, daily chemical and flavor and fragrance. It usually exists in essential oils in the form of free state and its corresponding ester, such as jasmine oil and ylang ylang oil. , Hyacinth Oil, Sesame Oil, Peru Balsam and Tolu Balsam, etc. Benzyl alcohol is widely used, and with the continuous development of new uses, the demand for benzyl alcohol is increasing. At present, the process of large-scale industrial production of benzyl alcohol is mainly to react with benzyl chloride and alkali to obtain the crude product of benzyl alcohol after hydrolysis, and obtain high-quality benzyl alcohol after rectification. The reaction formula i...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C33/22C07C29/132C07C29/80
CPCC07C29/132C07C29/80C07C33/22
Inventor 舒振操程娟孙波黄正望毛利民代飞朱明伟
Owner WUHAN YOUJI IND
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