Unlock instant, AI-driven research and patent intelligence for your innovation.

Method for recovering crystallization mother liquor in production process of 4-chloro-3, 5-dimethylphenol

A technology of dimethyl phenol and crystallization mother liquor, which is applied in chemical instruments and methods, preparation of organic compounds, organic chemistry, etc., can solve the problems of Ni-based catalysts such as easy coking, high price, and many components, and is beneficial to comprehensive Utilization, the effect of reducing production costs

Inactive Publication Date: 2021-03-12
安徽润衍科技有限公司
View PDF1 Cites 2 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Conventional vacuum distillation method: due to the high boiling point of the concentrate, many components, and heat sensitivity, it is difficult to achieve the purpose of recovery
Although catalytic hydrodechlorination technology is a direction to solve the problem, it is still a problem for industrial application due to the high price and high production cost of supported noble metal catalysts, and the characteristics of Ni-based catalysts are easy to coke and deactivate quickly.
In addition, the problem of reaction selectivity in hydrodechlorination increases the number of components after the reaction and complicates the post-treatment

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Image

Smart Image Click on the blue labels to locate them in the text.
Viewing Examples
Smart Image
  • Method for recovering crystallization mother liquor in production process of 4-chloro-3, 5-dimethylphenol
  • Method for recovering crystallization mother liquor in production process of 4-chloro-3, 5-dimethylphenol
  • Method for recovering crystallization mother liquor in production process of 4-chloro-3, 5-dimethylphenol

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0041] 100 g of crystalline mother liquor concentrate (OCMX 57.23%, PCMX 18.78%, DCMX 9.71%, MX 3.89%), add 25.4 g of sodium hydroxide, 300 g of water, stir and dissolve, add to the reaction kettle, and add 5 g of Pd / C (5% palladium content). After nitrogen replacement, hydrogen gas was introduced at 2.0 MPa, and the temperature was raised to 100°C for 6 hours of reaction. Sampling gas chromatography detects that each component does not react.

[0042] 100 g of crystalline mother liquor concentrate (OCMX 57.23%, PCMX 18.78%, DCMX 9.71%, MX 3.89%), add 25.4 g of sodium hydroxide, 300 g of water, stir and dissolve, add to the reaction kettle, and add 5 g of Raney Ni . After nitrogen replacement, hydrogen gas was introduced at 2.0 MPa, and the temperature was raised to 100°C for 6 hours of reaction. Sampling gas chromatography detected the proportion of each component as follows: OCMX 41.23%, PCMX 16.81%, DCMX 6.50%, MX 26.32%.

Embodiment 2

[0044]Take about 5000 ml of crystallization mother liquor under normal pressure, heat up to an internal temperature of 122°C and distill to recover the solvent. As the solvent is distilled out, the distillation temperature continues to rise. When the internal temperature reaches 180°C, stop heating and cool down to obtain a precipitated concentrate. Heat the precipitation concentrate to 60-70°C, turn on the vacuum water pump for vacuum distillation (-0.09MPa), further raise the temperature under reduced pressure and remove the organic solvent; after the internal temperature reaches 130°C, cool down to 60- 70°C, replace the water pump with a high vacuum oil pump (pressure: 400-500 Pa), gradually increase the temperature to 180°C to distill the mixture (containing OCMX 57.23%, PCMX 18.78%, DCMX 9.71%, MX 3.89%), and collect the mixed distillate The output is about 600 g, and the bottom residue is about 25-30 g.

Embodiment 3

[0046] (1) Take 100 g of the distillate obtained in Example 2, add 22.9 g of sodium hydroxide, 575 g of water, stir and dissolve, add to the reaction kettle, and add 2 g of Raney Ni. After nitrogen replacement, hydrogen gas was introduced at 2.0 MPa, and the temperature was raised to 100°C for 6 hours of reaction. The distribution of components detected by gas chromatography: OCMX: 1.20%, PCMX: 5.58%, DCMX: 0.23%, MX: 92.53%;

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

PUM

No PUM Login to View More

Abstract

The invention discloses a method for recovering crystallization mother liquor in the production process of 4-chlorine-3, 5-dimethylphenol, and the method comprises the following steps: (1) heating anddesolventizing the crystallization mother liquor to obtain a concentrated solution, continuing to distill and decoke the concentrated solution, and collecting the distillate, wherein the distillate contains MX, OCMX, PCMX (procalcitonin) and DCMX; (2) heating the distillate obtained in the step (1) in a sodium hydroxide aqueous solution under the action of a catalyst, and introducing hydrogen tocarry out a pressurization reaction; (3) after the reaction is finished, filtering while the solution is hot, recovering the catalyst, insulating and layering to obtain an organic layer and a water layer, and performing wastewater removal treatment on the water layer; (4) carrying out reduced pressure distillation on the organic layer obtained in the step (3) to remove water, and continuing to distill out 3, 5-dimethylphenol. According to the method, the crystallization mother liquor without utilization value is converted into products with economic benefits, the obtained recycled raw materials can be returned to the original production process, comprehensive utilization of the materials is realized, the production cost is reduced, and the method is suitable for industrialization.

Description

technical field [0001] The invention belongs to the technical field of fine chemicals, and in particular relates to a method for recovering crystallization mother liquor in the production process of 4-chloro-3,5-dimethylphenol. Background technique [0002] 4-Chloro-3,5-dimethylphenol (also known as 3,5-dimethyl-4-chloro-phenol; p-chloro-m-xylenol; p-chloro-m-xylenol, PCMX, CAS No.: 88- 04-0) is a low toxicity antibacterial agent, which has killing effect on most Gram-positive and negative bacteria, fungi and mold. [0003] PCMX is usually synthesized from m-xylenol (MX) by chlorination. Chlorinating agents include chlorine gas, sulfuryl chloride, etc. There are also reports on the preparation of this product under the catalysis of oxygen / HCl / copper salt (CN103351282 A) ; Usually there is a problem of reaction selectivity in the chlorination reaction, that is, the ortho-position substitution (OCMX) and the dichlorination isomer (DCMX) appear in the chlorination process of 3...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

Application Information

Patent Timeline
no application Login to View More
IPC IPC(8): C07C37/00C07C39/07C07C37/74
CPCC07C37/002C07C37/74C07C39/07
Inventor 耿敬坤李红雷
Owner 安徽润衍科技有限公司