阅读说明：本技术 一种八溴双酚醚类化合物析出结晶的方法 (Method for crystallizing octabromo bisphenol ether compound ) 是由 王艳红 孙仿建 于 2021-10-06 设计创作，主要内容包括：本发明公开了一种八溴双酚醚类化合物析出结晶的方法,是将溴化反应制备得到的八溴双酚醚类化合物二氯甲烷溶液加热浓缩除去溶剂二氯甲烷,得到比重为1.08～1.48g/m～(3)的糊状物料,加入糊状物料质量1～30wt.%的八溴双酚醚类化合物结晶,搅拌下析出八溴双酚醚类化合物结晶。本发明方法能够简单、快速地制备得到八溴双酚醚类化合物结晶产品,且产品纯度较高,可以达到99.5～99.6%。(The invention discloses a method for crystallizing octabromo bisphenol ether compound, which is to heat and concentrate dichloromethane solution of octabromo bisphenol ether compound prepared by bromination reaction to remove solvent dichloromethane to obtain specific gravity of 1.08-1.48 g/m 3 Adding octabromobisphenol ether compound crystals with the mass of 1-30 wt.% of the pasty material, and precipitating the octabromobisphenol ether compound crystals under stirring. The method can simply and quickly prepare octabromo bisphenol etherThe product is a crystalline product of the compound, and the purity of the product is high and can reach 99.5-99.6%.)

1. A method for crystallizing octabromo bisphenol ether compounds comprises the steps of heating and concentrating a dichloromethane solution of octabromo bisphenol ether compounds prepared by bromination reaction to remove a solvent dichloromethane to obtain octabromo bisphenol ether compounds with a specific gravity of 1.08-1.48 g/m³Adding octabromobisphenol ether compound crystals with the mass of 1-30 wt.% of the pasty material, and precipitating the octabromobisphenol ether compound crystals under stirring.

2. The method for crystallizing octabromo bisphenol ether compound according to claim 1, wherein the precipitated octabromo bisphenol ether compound crystals are washed with water, filtered and dried to obtain octabromo bisphenol ether compound crystal finished products.

3. The method for crystallizing an octabromo bisphenol ether compound according to claim 1 or 2, wherein said octabromo bisphenol ether compound comprises octabromo bisphenol S ether, methyl octabromo ether and octabromo ether.

4. The method for crystallizing an octabromo bisphenol ether compound according to claim 1 or 2, wherein the octabromo bisphenol ether compound crystals added to the paste are the same as the paste to which the octabromo bisphenol ether compound crystals are added.

5. The method for crystallizing an octabromobisphenol ether compound according to claim 1 or 2, wherein the octabromobisphenol ether compound is added to the paste in an amount of 5 to 30wt.% based on the mass of the paste.

6. The method for crystallizing octabromo bisphenol ether compound according to claim 1 or 2, wherein octabromo bisphenol ether compound is added to the paste material to crystallize, and then the mixture is stirred at 40 to 80 ℃ to crystallize.

7. The method for crystallizing an octabromobisphenol ether compound according to claim 6, wherein the crystallization is carried out under stirring for 5 to 60 minutes.

8. The method according to claim 2, wherein the crystals of octabromo bisphenol ether compound are washed with hot water at 50 ℃ under stirring.

9. The method for crystallizing an octabromobisphenol ether compound according to claim 8, wherein the amount of hot water used for washing is 1 to 3 times the mass of the octabromobisphenol ether compound crystals.

10. The method for crystallizing an octabromobisphenol ether compound according to claim 8, wherein the washing time is 10 to 30 min.

Technical Field

The invention belongs to the technical field of preparation of flame retardants, relates to a preparation method of octabromo bisphenol ether compounds, and particularly relates to a method for precipitating crystals from octabromo bisphenol ether compounds.

Background

More than 60 flame retardant factories in China can produce more than 50 flame retardant products, mainly comprising bromine and phosphorus series flame retardants. Among them, the bromine flame retardants are the most important series, accounting for about 30% of the organic flame retardants in China. In particular, after hexabromocyclododecane is listed in a forbidden list by the stockholm convention, manufacturers produce octabromobisphenol ether products in a lot of changes, so that the octabromobisphenol ether products are increasing at a rate of 10% per year.

Octabromobisphenol ether flame retardant products include octabromobisphenol S ether (CAS number 42757-55-1), methyl octabromoether (CAS number 97416-84-7) and octabromoether (CAS number 21850-44-2), as a white powder in appearance, low in toxicity, soluble in benzene, acetone, chloroform, etc., and insoluble in water and hexanol. The octabromobisphenol ether flame retardant is a high-efficiency flame retardant containing aromatic bromine and aliphatic bromine, has excellent thermal stability and light stability when being used as a general additive flame retardant, and is mainly used in resins such as polypropylene, polyethylene, polyvinyl chloride and the like.

The production process of octabromo bisphenol ether series products is the same, firstly tetrabromobisphenol A or S diene alkyl ether is generated by condensing chloroalkene alkane and bisphenol compounds, and then bromination reaction is carried out on the tetrabromobisphenol A or S diene alkyl ether and bromine in dichloromethane, and the corresponding octabromo bisphenol ether compounds are prepared.

The octabromo bisphenol ether compound obtained by bromination is a compound with particularly high solubility in dichloromethane, and can be crystallized only by removing dichloromethane through concentration.

However, in actual industrial production, precipitation of crystals of octabromobisphenol ether compounds has been difficult.

No matter how the solvent dichloromethane is not concentrated, even if the material in the crystallization kettle is concentrated into a paste, the crystallization of octabromobisphenol ether cannot be obtained. In this case, since the amount of dichloromethane was slightly larger, the material was dissolved in dichloromethane, and even if the seed crystal was added, the saturation of the solution was not reached and there was no change, and it was not helpful to add a small amount of seed crystal.

However, if the dichloromethane is continuously concentrated and removed, after the critical point of crystallization precipitation is broken through, the octabromobisphenol ether can suddenly generate a large amount of crystals instantly, the crystals are held into a large lump in the crystallization kettle, the stirring speed can only be increased, and the large lump of crystals are broken into small blocks after being intensively stirred for several hours.

Therefore, the octabromobisphenol ether obtained in the crystallization kettle is hard small balls with different sizes which are stirred and smashed, and a powdery finished product is obtained by smashing the octabromobisphenol ether through a smashing machine. However, the octabromo bisphenol ether crystal product in the form has poor appearance and poor fluidity, and the purity of the product is not high, and is generally only about 99.1-99.3%.

Based on the reason of instantaneous sudden large-amount crystallization, more dichloromethane mother liquor is inevitably coated in the smashed small balls, and the dichloromethane mother liquor contains more impurities, such as impurities brought by raw materials, mono-substituted impurities of etherification reaction and bromination reaction and the like, so that the purity of the final prepared product is low.

Meanwhile, the product with the shape and the purity is easy to absorb moisture, and the product is often hardened into a large block during use, so that a lot of troubles are caused for subsequent production enterprises.

Because the industrial problem of crystallization is not well solved, the selling price of octabromo bisphenol ether products in China is 15% lower than that of imported products.

The applicant's patent application 202111146815.X proposes a method for precipitating methyl octabromoether crystals, which is to concentrate dichloromethane in a crystallization kettle until materials are suddenly agglomerated into a large block, continue to raise the temperature to evaporate residual dichloromethane until the materials are molten, then under the protection of nitrogen with the pressure of 0.3MPa, enable the molten materials to be extruded to enter a large amount of cold water with strong stirring through a pattern plate with the aperture of 2mm, immediately break to obtain small cylindrical particles, and obtain the methyl octabromoether crystals after filtration and drying.

The method is simple to operate, the obtained product has good crystallinity and fluidity, but the crystallization of the product is carried out in a high-temperature molten state, so the color of the final product is yellowish, the whiteness does not meet the requirement of 85, and the method can only be used for downstream products with low requirements.

Adding proper auxiliary agent into octabromobisphenol ether with powder and poor fluidity for granulation, and obtaining a granulation product with good fluidity and difficult agglomeration. However, the granulation cost of the product is high, and the product is only suitable for downstream high-end products. The Japanese product imported in China at present is the high-end product after granulation.

Disclosure of Invention

The invention aims to provide a method for precipitating and crystallizing octabromo bisphenol ether compound, so as to simply and quickly prepare octabromo bisphenol ether compound crystal product with higher purity.

The method for precipitating and crystallizing the octabromo bisphenol ether compound comprises the step of heating and concentrating a dichloromethane solution of the octabromo bisphenol ether compound prepared by bromination reaction to remove a dichloromethane solvent to obtain a specific gravity of 1.08-1.48 g/m³Adding octabromobisphenol ether compound crystals with the mass of 1-30 wt.% of the pasty material, and precipitating the octabromobisphenol ether compound crystals under stirring.

Furthermore, the method of the invention also comprises the steps of washing the precipitated octabromo bisphenol ether compound crystal with water, filtering and drying to obtain the octabromo bisphenol ether compound crystal finished product.

Generally, during the heating concentration process of the octabromo bisphenol ether compound dichloromethane solution, the temperature of the material will rise slowly as the solvent dichloromethane is distilled off. When the temperature of the materials is raised to 45-55 ℃, the materials can be concentrated to obtain the specific gravity of 1.08-1.48 g/m³The pasty material of (2).

Specifically, the method for crystallizing the octabromo bisphenol ether compound is suitable for preparing the octabromo bisphenol ether compound crystal including octabromo bisphenol S ether, methyl octabromo ether, octabromo ether and the like.

Wherein, the added octabromo bisphenol ether compound crystal and the added pasty material are the same substance.

More preferably, the octabromo bisphenol ether compound crystal is added into the pasty material, wherein the octabromo bisphenol ether compound crystal accounts for 5-30 wt% of the mass of the pasty material.

Further, the octabromo bisphenol ether compound is added into the pasty material for crystallization, and then the pasty material is stirred at the temperature of 40-80 ℃ for crystallization.

Furthermore, the stirring and crystallization time is preferably 5-60 min.

Specifically, the precipitated octabromo bisphenol ether compound crystals are stirred and washed by hot water at 50 ℃.

More specifically, the amount of hot water used for washing is 1-3 times of the crystal quality of the octabromo bisphenol ether compound.

The preferable washing time is 10-30 min.

In the method for separating out crystals of octabromo bisphenol ether compounds, the bromination reaction for preparing octabromo bisphenol ether compounds is a conventional method.

Wherein the molar ratio of the bromination reaction raw material to bromine is 1: 2-2.05, the bromination reaction is carried out at 30-50 ℃, and the reaction time is preferably 1-3 h.

Furthermore, in the bromination reaction, the amount of dichloromethane serving as a solvent is preferably 2-4 times of the mass of the raw materials of the bromination reaction.

Octabromobisphenol ether compounds are used as solutes and have extremely high solubility in the solvent dichloromethane. Therefore, even when only a very small amount of methylene chloride is used as a solvent, it is difficult to obtain solid octabromo bisphenol ether crystals smoothly by means of conventional concentration or crystallization induction.

However, when the octabromobisphenol ether compound methylene chloride solution is concentrated to a paste, a large amount of octabromobisphenol ether is actually precipitated, but owing to the considerable affinity between octabromobisphenol ether and methylene chloride, the octabromobisphenol ether crystals produced are present as fine particles, which are covered with a thin layer of methylene chloride on the outside. At this time, even if the paste was filtered, only a large solid without crystallization was obtained.

In order to destroy the balance between solid and liquid, the invention adds a large amount of octabromo bisphenol ether crystal finished product into the pasty material at one time under stirring, so that only a small amount of dichloromethane in the pasty material is changed into a solvent with extremely small relative amount, an organic layer wrapped on the surface of the fine octabromo bisphenol ether is destroyed, collision and combination among fine particles are increased, and crystals are formed, and then the pasty material is changed into almost dry crystals with good appearance quickly under stirring.

The method for precipitating the crystals of the octabromo bisphenol ether compound is different from the conventional induced crystallization method of adding the seed crystal, but a large amount of crystals are added into a pasty material, residual dichloromethane is absorbed, the content of the solvent is reduced by increasing the dissolving mass, and the environment is changed to precipitate the crystals. On the other hand, when the octabromobisphenol ether compound solution is added with an extra amount of seed crystals, no crystal is precipitated. Thus, the crystallization method of the present invention may also be referred to as an "extrusion crystallization method".

The octabromo bisphenol ether compound precipitated by the method has good crystal form, is easy to filter, is easy to spin-dry dichloromethane mother liquor, and finally the purity of the prepared product is high and can reach 99.5-99.6%.

Detailed Description

The following examples are given to further illustrate the embodiments of the present invention. The following examples are only for more clearly illustrating the technical solutions of the present invention so as to enable those skilled in the art to better understand and utilize the present invention, and do not limit the scope of the present invention.

The names and the abbreviations of the experimental methods, production processes, instruments and equipment related to the embodiments of the present invention are all conventional names in the art, and are clearly and clearly understood in the related fields of use, and those skilled in the art can understand the conventional process steps and apply the corresponding equipment according to the names, and implement the process according to the conventional conditions or the conditions suggested by the manufacturers.

The raw materials and reagents used in the examples of the present invention are not particularly limited in terms of their sources, and are all conventional products commercially available. They may also be prepared according to conventional methods well known to those skilled in the art.

Example 1.

130g of dry tetrabromobisphenol S-bis (2, 3-allyl) ether were weighed into a 1000mL three-necked flask with 280g of methylene chloride added thereto under stirring, the temperature was raised to 35 ℃ and 65g of bromine was added dropwise over 2 hours.

After the reaction, dichloromethane was distilled off by heating under normal pressure. During the continuous evaporation of dichloromethane, the temperature of the material slowly rose.

When the temperature of the material rises to 47 ℃, the reaction product is concentrated to a specific gravity of 1.21g/m³Is pasty.

The evaporation of methylene chloride was stopped, 10g of tetrabromobisphenol S-bis (2, 3-allyl) ether crystals were added to the pasty reaction product at a time, and the mixture was crystallized at 52 ℃ for 50 minutes with stirring to form a reaction product in the form of well-crystallized crystals.

And adding 500mL of hot water with the temperature of 50 ℃ into the reaction product crystal, stirring and washing for 10min, cooling to 10 ℃, filtering, drying a filter cake to obtain a finished product of the octabromo bisphenol S ether crystal, and testing to obtain the finished product with the purity of 99.51%.

Example 2.

150g of dry tetrabromobisphenol A-bis (2, 3-allyl) ether were weighed into a 1000mL three-necked flask with 320g of methylene chloride added thereto under stirring, the temperature was raised to 35 ℃ and 77g of bromine was added dropwise over 1.5 hours.

After the reaction, dichloromethane was distilled off by heating under normal pressure. During the continuous evaporation of dichloromethane, the temperature of the material slowly rose.

When the temperature of the feed rose to 46 ℃, the reaction product was concentrated to a specific gravity of 1.23g/m³Is pasty.

The evaporation of methylene chloride was stopped, 15g of tetrabromobisphenol A-bis (2, 3-allyl) ether was added to the pasty reaction product at a time to crystallize it at 40 ℃ with stirring for 60min, and the reaction product was crystallized to form a well-crystallized crystal.

Adding 600mL of hot water with the temperature of 50 ℃ into the reaction product crystal, stirring and washing for 10min, cooling to 10 ℃, filtering, drying a filter cake to obtain a finished product of the octabromoether crystal, and testing to obtain the finished product with the purity of 99.53%.

Example 3.

140g of dry tetrabromobisphenol A-bis (2, 3-ene (2-methyl) propyl) ether were weighed into a 1000mL three-necked flask with 280g of methylene chloride added thereto under stirring, and the temperature was raised to 40 ℃ to complete the dropwise addition of 71.7g of bromine over 3 hours.

After the reaction, dichloromethane was distilled off by heating under normal pressure. During the continuous evaporation of dichloromethane, the temperature of the material slowly rose.

When the temperature of the material rises to 48 ℃, the reaction product is concentrated to a specific gravity of 1.18g/m³Is pasty.

The evaporation of methylene chloride was stopped, 25g of tetrabromobisphenol A-bis (2, 3-ene (2-methyl) propyl) ether crystals were added to the pasty reaction product at a time, and the mixture was crystallized with stirring at 50 ℃ for 30 minutes to form a reaction product in the form of well-crystallized crystals.

And adding 550mL of hot water with the temperature of 50 ℃ into the reaction product crystal, stirring and washing for 15min, cooling to 10 ℃, filtering, drying a filter cake to obtain a finished product of the methyl octabromoether crystal, and testing to obtain the finished product with the purity of 99.55%.

The above embodiments of the present invention are not intended to be exhaustive or to limit the invention to the precise form disclosed. Various changes, modifications, substitutions and alterations to these embodiments will be apparent to those skilled in the art without departing from the principles and spirit of this invention.