CN104926599A - Method for preparing high-purity 4,4'-bis(chloromethyl)-1,1'-biphenyl under novel solvent system - Google Patents

Abstract

The invention relates to a method for preparing high-purity biphenyl benzyl dichloride under a novel solvent system, which belongs to the field of chemical synthesis, in particular to a method for preparing high-purity biphenyl benzyl dichloride under a novel solvent system using biphenyl as a raw material . By using a novel solvent, the biphenyl benzyl dichloride is prepared in two steps of chloromethylation reaction and refining with the biphenyl as a raw material, and the yield is more than 80% and the purity is more than 99%. The product of the invention changes the traditional solvent system, significantly improves the yield and purity of the product, reduces the potential safety hazard of the low-boiling solvent in the production process, and the solvent is convenient for recycling.

Description

A method for preparing high-purity biphenyl dichlorobenzyl under novel solvent system

technical field

The invention relates to a method for preparing high-purity biphenyl benzyl dichloride in a novel solvent, belonging to the technical field of chemical synthesis.

Background technique

4,4'-bis(chloromethyl)biphenyl (4,4'-bis(chloromethyl)biphenyl, BCMB), also known as biphenyl dichlorobenzyl, is a fine chemical intermediate and can be used as a single component of synthetic resin It can also be used as a raw material for biphenyl derivatives. At present, it is mainly used for the synthesis of fluorescent whitening agent, which has a good whitening effect on polyamide fiber and protein fiber; it has suitable affinity and good diffusion performance on cellulose fiber, and can make cellulose fiber rapidly in a short time. It achieves high whiteness; at the same time, it has excellent resistance to oxygen bleaching, chlorine bleaching, strong acid and alkali resistance and excellent perspiration fastness; and its whiteness is very stable, and the loss during washing, dyeing and drying Rarely, the whitening effect is very obvious, and it is not easy to change color during storage, so it is known as a super fluorescent whitening agent. At present, my country mainly relies on imports for this type of fluorescent whitening agent. Although there are domestic manufacturers producing it in recent years, there is a considerable gap in quality compared with foreign products, and the production scale is relatively small. High-purity (99%) biphenyl benzyl dichloride can be used to synthesize liquid crystal compounds or polymers, and can also be used as an intermediate for epoxy resins, polyvinyl chloride resins, and polyester resin flame retardants. This high-quality product is currently mainly imported to meet domestic demand. At present, the commonly used technology at home and abroad is to use biphenyl and paraformaldehyde as raw materials, and to synthesize it through Blanc chloromethylation reaction under the action of catalyst ZnCl ₂ . The preparation method is simple and easy to operate, and has wide application value in industry.

The overall reaction can be expressed as:

US3001975 reports the process of preparing 4,4'-dichloromethylbiphenyl from biphenyl and paraformaldehyde under the catalysis of zinc chloride, acetic acid and concentrated hydrochloric acid, but the final product contains a large number of monosubstituted products, and the literature does not give refinement method.

In the document "4,4'-bis(chloromethyl)biphenyl synthesis new process", people such as Ma Weixing set forth that by biphenyl as raw material, first synthesize 4,4'-bis(hydroxymethyl)biphenyl, and then pass The synthesis of biphenyl benzyl dichloride from thionyl chloride consists of four steps, the reaction process is relatively complicated, and the yield is only 61.5%.

Chinese patent CN101928198 discloses a production process of biphenyl dichlorobenzyl, which uses petroleum ether as a solvent, biphenyl, paraformaldehyde and zinc chloride as raw materials, and uses the biphenyl dichlorobenzyl produced in the production as waste residue The treated by-products are recycled and decolorized by activated carbon to obtain biphenyl benzyl dichloride with a high yield. However, a large number of by-products are generated during the production process, and using petroleum ether or cyclohexane as a solvent with a low boiling point has a huge potential safety hazard in actual industrial production.

Contents of the invention

The invention discloses a method for preparing high-purity biphenyl dichlorobenzyl in a novel solvent. By improving the solvent used in the current process and using a new type of solvent, impurities such as monochlorinated or polychlorinated substances are separated from the product biphenyldichlorobenzyl during the reaction process, which not only greatly improves the production safety, but also effectively The quality, yield (>80%) and purity (>99%) of the product have been greatly improved, the value of the product has been enhanced, and the demand for high-tech products has been met; the raw material has been significantly reduced by pressurizing the reaction system. The amount of input greatly improves the conversion rate of raw materials; by strictly controlling the reaction temperature, the generation of side reactions is fully suppressed, and the selectivity of products is obviously improved, which is in line with the principle of atom economy.

The following are main technical solutions of the present invention:

Add new solvent I, biphenyl, paraformaldehyde and catalyst in sequence in the reaction device, the reaction temperature is controlled at 25-80°C, the reaction time is 25-35 hours, and the chloromethylation reaction is carried out under the condition of passing dry HCL gas, HPLC Follow up the reaction; after the reaction, since impurities such as monochlorine substitutes or polychlorine substitutes are dissolved in solvent Ⅰ, the crude material is directly washed with water, filtered and recrystallized in solvent Ⅱ, separated from solid and liquid, and dried directly without decolorization treatment. Purity of biphenyl benzyl dichloride (HPLC>99%).

The solvent I is toluene, chlorobenzene, xylene, methanol, ethanol, ethylene glycol, formic acid, acetic acid, propionic acid, butyric acid, isobutyric acid, isovaleric acid, valeric acid, 3-methylvaleric acid, One or more of 4-methylpentanoic acid, hexanoic acid, heptanoic acid, octanoic acid, isooctanoic acid, nonanoic acid, methylene chloride, chloroform, and carbon tetrachloride.

The molar ratio of each component in the solvent I is 1:0-15:0-7.

The catalyst is one or two of aluminum chloride, tin chloride, copper chloride, phosphoric acid, hydrochloric acid, sulfuric acid and zinc chloride.

The molar ratio of the biphenyl, paraformaldehyde and catalyst is 1:0-3:0-2.

The molar ratio of the biphenyl to the solvent I is 1:0-3.

The solvent II used for the recrystallization is one or two of toluene, chlorobenzene, xylene, benzene, ethanol, methanol, butanol, formic acid, acetic acid, ethyl acetate, and propyl acetate.

Compared with prior art, the beneficial effect that the present invention has is:

(1) The present invention is an industrialized method for preparing high-purity biphenyl benzyl dichloride;

(2) Improve the reaction solvent system to improve product quality and production safety;

(3) The solvent used is convenient for recycling;

(4) By controlling the reaction temperature, the occurrence of side reactions is obviously suppressed, and the selectivity of the product is improved;

(5) The conversion rate of raw materials is significantly improved.

Description of drawings

Fig. 1 is a flow chart of the present invention.

Detailed ways

Below in conjunction with specific example, further set forth the present invention.

Example 1

A method for preparing high-purity biphenyl benzyl dichloride under a novel solvent system: 2.00mol toluene, 0.50mol butyric acid, 1.00mol biphenyl, 2.00mol paraformaldehyde, 0.55mol aluminum chloride are successively put into a reaction kettle, and stirred Evenly, pass dry HCL gas, control the temperature at 30-50°C, and react for 30 hours. After the reaction is finished, the materials in the reactor are washed with water and filtered to obtain a crude product, which is then recrystallized with toluene, filtered and dried to obtain a refined product. The detected product has a purity of 99.15% and a yield of 82.2%.

Example 2

A method for preparing high-purity biphenyl benzyl dichloride under a novel solvent system: 1.50mol chlorobenzene, 1.00mol formic acid, 1.00mol biphenyl, 2.00mol paraformaldehyde, 0.70mol zinc chloride are successively put into a reaction kettle, and stirred Evenly, pass through dry HCL gas, control the temperature at 25-55°C, and react for 28 hours. After the reaction is finished, the materials in the reactor are washed with water and filtered to obtain a crude product, which is then recrystallized with benzene and ethanol, filtered and dried to obtain a refined product. The detected product has a purity of 99.26% and a yield of 84.1%.

Example 3

A method for preparing high-purity biphenyl benzyl dichloride under a novel solvent system: 6.00mol ethanol, 1.50mol propionic acid, 3.00mol biphenyl, 6.00mol paraformaldehyde, 1.65mol aluminum chloride are successively put into a reaction kettle, and stirred Evenly, pass dry HCL gas, control the temperature at 35-55°C, and react for 30 hours. After the reaction is finished, the materials in the reactor are washed with water and filtered to obtain a crude product, which is then recrystallized with xylene, filtered and dried to obtain a refined product. The detected product has a purity of 99.42% and a yield of 84.7%.

Example 4

A method for preparing high-purity biphenyl benzyl dichloride under a novel solvent system: 1.00mol toluene, 0.25mol isooctanoic acid, 0.50mol biphenyl, 1.00mol paraformaldehyde, 0.3mol zinc chloride are successively put into a reaction kettle, and stirred Uniformly, pass dry HCL gas, pressurize 50kpa, control temperature 40-65°C, react for 30 hours. After the reaction is completed, the materials in the reactor are washed with water and filtered to obtain a crude product, which is then recrystallized with acetic acid, filtered and dried to obtain a refined product. The detected product has a purity of 99.17% and a yield of 83.5%.

Example 5

A method for preparing high-purity biphenyl benzyl dichloride under a novel solvent system: 6.00mol toluene, 1.50mol 4-methylpentanoic acid, 3.00mol biphenyl, 6.00mol paraformaldehyde, 1.65mol chlorine Aluminum, stir evenly, pass through dry HCL gas, control the temperature at 55-80°C, and react for 25 hours. After the reaction is completed, the materials in the reactor are washed with water and filtered to obtain a crude product, which is then recrystallized with toluene and methanol, filtered and dried to obtain a refined product. The purity of the tested product was 99.25%, and the yield was 80.7%.

Claims (9)

1. under novel dissolvent system, prepare a method for high purity biphenyl-benzyl dichloride, comprise the steps:

(1) joined in reaction unit with novel dissolvent I by a certain amount of biphenyl and mix, paraformaldehyde and catalyzer join in reaction unit in batches according to certain mol proportion, and under the condition passing into dry HCL gas, chloromethylation is carried out in heating;

(2) refining: the material system after reaction being terminated obtains high purity biphenyl-benzyl dichloride product after washing, filtration, recrystallization, drying.

2. a kind of method preparing high purity biphenyl-benzyl dichloride under novel dissolvent system as claimed in claim 1, it is characterized in that: novel dissolvent I is toluene, chlorobenzene, dimethylbenzene, methyl alcohol, ethanol, ethylene glycol, formic acid, acetic acid, propionic acid, butyric acid, isopropylformic acid, isovaleric acid, valeric acid, 3 methylvaleric acid, 4-methylvaleric acid, caproic acid, enanthic acid, sad, one or more in the middle of isocaprylic acid, n-nonanoic acid, methylene dichloride, chloroform, tetracol phenixin.

3. a kind of method preparing high purity biphenyl-benzyl dichloride as claimed in claim 1, is characterized in that: in the middle of the novel dissolvent I described in step (1), the mol ratio of each component is 1:0 ~ 15:0 ~ 7.

4. a kind of method preparing high purity biphenyl-benzyl dichloride under novel dissolvent system as claimed in claim 1, is characterized in that: the mol ratio of the biphenyl described in step (1), paraformaldehyde, catalyzer is 1:0 ~ 3:0 ~ 2.

5. a kind of method preparing high purity biphenyl-benzyl dichloride under novel dissolvent system as claimed in claim 1, is characterized in that: the biphenyl described in step (1) and the mol ratio of novel dissolvent I are 1:0 ~ 3.

6. a kind of method preparing high purity biphenyl-benzyl dichloride under novel dissolvent system as claimed in claim 1, is characterized in that: the catalyzer described in step (1) is one or both in the middle of aluminum chloride, tin chloride, cupric chloride, phosphoric acid, hydrochloric acid, sulfuric acid, zinc chloride.

7. a kind of method preparing high purity biphenyl-benzyl dichloride under novel dissolvent system as claimed in claim 1, is characterized in that: the heating and temperature control described in step (1) is 25 ~ 80 DEG C.

8. a kind of method preparing high purity biphenyl-benzyl dichloride under novel dissolvent system as claimed in claim 1, is characterized in that: the recrystallization solvent for use II described in step (2) is toluene, one or both in chlorobenzene, dimethylbenzene, benzene, ethanol, methyl alcohol, butanols, formic acid, acetic acid.

9. a kind of method preparing high purity biphenyl-benzyl dichloride as claimed in claim 1, is characterized in that: in the middle of the solvent II described in step (2), the mol ratio of each component is 1:0 ~ 3:0 ~ 7.