JPH04134039A - Production of ring-brominated styrene monomer - Google Patents

Abstract

PURPOSE:To obtain the title substance while suppressing polymerization by reacting a ring-brominated beta-bromoethylbenzene with an alcohol solution of alkali metal hydroxide in the presence of a compound having 3,5-di-tert. butyl-4- hydroxyphenyl group. CONSTITUTION:A ring-brominated beta-bromoethylbenzene is reacted with an alcohol solution (e.g. 5-30wt.% methanol solution of NaOH) of alkali metal hydroxide in the presence of a polymerization inhibitor [e.g. 2,4-bis-(n- octylthio)-6-(4-hydroxy-3,5-di-tert. butylanilino)-1,3,5-triazine] at 20-60 deg.C to produce the title substance. The polymerization inhibitor is used in an amount of 0.01-0.5 pts.wt. based on 100 pts.wt. raw material compound. Polymerization in production can remarkably be suppressed by using the polymerization inhibitor and the objective product prevented in coloring can be obtained. The title substance is useful as a reactive flame-retardant of high polymer material and monomer for optical material.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for producing a cyclic brominated styrene monomer that suppresses polymerization during the production of the cyclic brominated styrene monomer and prevents coloring.

Cyclobrominated styrene monomers, particularly mono-, di-, and tribromostyrene, are useful compounds as reactive flame retardants for polymeric abrasive materials or as hexamers for optical materials.

[Prior Art] Ring-brominated styrene monomers have extremely high polymerizability, as described in Polymer (1969), Vol. 10, pp. 479-487. For example, the above-mentioned paper shows that the polymerization rate of dipromostyrene is more than 10 times faster than that of styrene, and that the thermal polymerization rate is faster in the order of tribromostyrene, dipromostyrene, and styrene. When producing or storing such highly polymerizable monomers, a polymerization inhibitor is added to the monomer.

British Patent No. 1,230,979 describes that dipromostyrene is stabilized by picric acid or a mixture of picric acid and quinones or phenols such as hydroquinone, benzoquinone, and t-butylcatechol. However, picric acid has the undesirable property of being impact sensitive and causing the monomer to turn yellow.

U.S. Pat. No. 4,276,189 discloses that metal oxides are
A method is described for inhibiting the polymerization of dipromostyrene by adding with or without additional stabilizers such as butylcatechol and benzoquinone. However, this method is only effective when transporting or storing monomers, and its effectiveness is very small during the production carried out in the present invention. Although the reason for this is not clear, it is thought that the inhibitor is altered by the alkali metal hydroxide used during production, reducing its polymerization inhibiting effect.

Furthermore, JP-A-64-63536 discloses N,N dialkylhydroxylamines as stabilizers for ring-brominated styrene monomers.

However, although this method is also effective when transporting or storing monomers, it has no or very small effect during the production performed according to the present invention. U.S. Pat. No. 4,338,474 discloses phenothiazine, a compound having a phenothiazine skeleton, or a mixture thereof with a dihydroxyl aromatic compound, and U.S. Pat. A mixture of or US 571 No. 4376221Jr3,
Alkylphenyl diamines are each indicated as stabilizers for dipromostyrene. Although they are effective to some extent during production according to the present invention, phenothiazines and alkylphenylene diamines are undesirable because they are colored by alkali metal hydroxides and cause the monomers to become colored. This is reflected in U.S. Patent No. 46330.
This also applies to the manufacturing method shown in No. 26, and the specification also states that the monomer is colored yellow. When such colored monomers are homopolymerized, or made into various copolymers or graft polymers and blended into various resins, the blended resins are also colored, resulting in major problems such as appearance.

[Problems to be Solved by the Invention] An object of the present invention is to provide a method for industrially producing a ring-brominated styrene monomer that suppresses polymerization during the production of the ring-brominated styrene monomer and prevents coloring. It's about doing.

[Means for Solving the Problems] The present inventors have proposed a polymerization inhibitor in a method for producing a cyclic brominated styrene monomer by avoiding the reaction between cyclic brominated β-bromoethylbenzene and an alcoholic solution of an alkali metal hydroxide. As a result of intensive study, we found that 35-di-t is present in the molecule.
- by adding and reacting a compound having at least one "two" butyl-4-hydroxyphenyl groups,
The inventors discovered the unique fact that the polymerization of the produced cyclic brominated styrene monomer can be extremely effectively suppressed, and that it is possible to obtain a cyclic brominated styrene monomer with significantly suppressed coloring, which led to the completion of the present invention. .

That is, the present invention provides a method for producing a cyclic brominated styrene monomer by reacting a cyclic brominated β-bromoethylbenzene with an alcoholic solution of an alkali metal hydroxide. It is characterized by reacting in the presence of a compound having at least one 4-hydroxyphenyl group to suppress polymerization of the resulting ring-brominated styrene monomer and at the same time obtain a ring-brominated styrene monomer with suppressed coloring. This is a method for producing ring brominated styrene monomer.

The present invention will be explained in detail below.

[Function] The reaction method carried out in the present invention is a method in which ring-brominated β-bromoethylbenzene is reacted with an alcoholic solution of an alkali metal hydroxide.

The ring brominated β-bromoethylbenzene referred to in the present invention is
It is a compound in which at least one hydrogen atom in an aromatic ring is replaced with a bromine atom. Specifically, β-bromoethyl monobromobenzene, β-bromoethyldibromobenzene, β-bromoethyltribromobenzene, β-bromoethyltetrabromobenzene, β-bromoethylpentabromobenzene, and mixtures thereof. Point. Especially β-bromoethyl monobromobenzene, β-bromoethyl dibromobenzene,
β-bromoethyltribromobenzene and mixtures thereof are compounds that can be suitably used in the present invention. These can be obtained by known methods. For example, polymer (196
10, pp. 479-487, it can be obtained by ring bromination of β-bromoethylbenzene with bromine in the presence of anhydrous ferric chloride.

The alkali metal hydroxide used in the present invention is NaOH
and KOH. Mixtures of these can also be used. The amount used is generally 1 mol to 4 mol, preferably 1.1 mol to 2.1 mol, per 1 mol of ring-brominated β-bromoethylbenzene. The alcohol referred to in the present invention is an aliphatic alcohol having 1 to 3 carbon atoms, and specifically includes methanol, ethanol, propatool, and the like. The concentration of the alkali metal hydroxide used in the alcohol solution is 5% by weight to 50% by weight.
The amount is preferably from 5% to 30% by weight. The reaction temperature in the present invention is usually selected between 0°C and 80°C, preferably between 20°C and 60°C. 0
If the temperature is below 80°C, the reaction rate is extremely slow and it takes a long time to complete the reaction, and if the temperature exceeds 80°C, the amount of polymer produced increases undesirably. Examples of the charging method include a method in which an alcoholic solution of an alkali metal hydroxide is added dropwise to ring-brominated β-bromoethylbenzene to cause a reaction, the reverse method, or a method in which both are added dropwise at the same time.

In the molecule used as a polymerization inhibitor in the present invention, 3゜5-di-
At least one t-butyl-4-hydroxyphenyl group
The compound having more than 1 phenol is a compound having a structure generally called a hindered phenol. For example, specifically 1-[2-+3(3,5-di-t-butyl-4-hydroxyphenyl)propionyloxy)ethyl]-4
-+3(3,5-di-t-butyl-4-hydroxyphenyl)propionyloxyl-2,2,6,6tetramethylpiperidine, hereinafter written as 5LS2626>, 2.4
-bis-(n-octylthio)6-(4-hydroxy-
3,5-di-t-butylanilino)-1,3,5-1-
After riazine, it is not written as IRG565〉, octadecyl-
3-(3゜5-di-t-butyl-4-hydroxyphenyl)propionate <hereinafter referred to as IRG1076>, N
, N'-hexamethylenebis(3,5-di-t-butyl-4-hydroxy-hydrocinnamamide) IRG
], 098>, N, N'-bis[3-(
3,5-di-t-butyl-4-hydroxyphenyl)propionate hydrazine (hereinafter referred to as ■RGMD1024), 2-(3,5-di-t-butyl-4-hydroxybenzyl)-2-n-butylmalonic acid bis (1, 2, 2,
6,6-bentamethyl-4-piperidyl TlN1
44). These are added in advance to ring-brominated β-bromoethylbenzene and reacted, and the amount used is usually 0.005 to 1.0 parts by weight, preferably 0.01 parts by weight, per 100 parts by weight of ring-brominated β-bromoethylbenzene. ~0.5 part by weight is chosen. 0.
If the amount is less than 0.005 parts by weight, the polymerization inhibitory effect will be small;
．． If it exceeds 0 parts by weight, it is not economical and therefore undesirable.

After the reaction of the cyclic brominated styrene monomer, water is added to the reaction solution at a level that allows complete phase separation of the cyclic brominated styrene monomer, and after branching and removing the alkali metal hydroxide and alkali metal salt, the organic layer is separated. Can be separated and recovered by removing solvent and dehydrating.

[Effects of the Invention] As mentioned above, quinone-based, amine-based, and phenothiazine-based inhibitors have been proposed as known polymerization inhibitors for ring-brominated styrene monomers, and specifically, hydroquinone monomethyl ether, P- Phenyl diamine, N, N'
-diphenyl-P phenylenediamine, phenothiazine and the like. Although these are effective for storage stabilization of ring brominated styrene monomers, they are less effective as polymerization inhibitors during the production of the present invention. In addition, the resulting ring brominated styrene monomer is significantly colored.

On the other hand, by applying the method of the present invention during the production of styrene-based monomers, polymerization during production can be significantly suppressed, and a styrene-based monomer that is prevented from being colored can be obtained.

The production method of the present invention is extremely simple, has great industrial value, and is highly practical.

[Examples] Hereinafter, the method of the present invention will be specifically explained using Examples, but the present invention is not limited to these Examples.

Incidentally, the amount of conjugates in the raw brominated styrene monomer produced was determined by high performance liquid chromatography.

On the other hand, the degree of coloring is determined by d
This was determined by comparing the measured absorbance (ABS).

・Measurement cell - 10 m square quartz cell ・Measurement wavelength - 460 nm Example 1 A base β-bromoethylbenzene mixture (β -bromoethyldibromobenzene 83.0% by weight, β-bromoethyltribromobenzene 12.8% by weight β = bromoethylmonobromobenzene 4
．． 2% by weight) 1.00g, and 5LS2626 0
．． 1. g, 10 wt% NaOH under stirring at 40°C.
175.0 g of /methanol solution was added dropwise over 3 hours. After the dropwise addition was completed, the mixture was aged at the same temperature for 1 hour while stirring. Thereafter, the mixture was cooled, and 200 ml of water was added near room temperature, stirred for 10 minutes, and left to stand still. The reaction solution was separated into two phases: a base styrene monomer mixture phase and an aqueous phase containing methanol, water, by-product sodium bromide, and excess NaOH. The base styrene monomer phase obtained by branching this was mixed with 50% water.
The mixture was washed twice with water in a warehouse, and then dried over anhydrous sodium sulfate to obtain 7.5.8 g of a crude styrene monomer mixture.

The results are shown in Table 1.

Example 2 The reaction and post-treatment were carried out using the same raw materials, amount of charge, and conditions as in Example 1, except that SLS2626 was replaced with IRG565. The results are shown in Table 1.

Example 3 The reaction and post-treatment were performed using the same raw materials, charging nails, and conditions as in Example 1, except that SLS2626 was replaced with IRG], 076. The results are shown in Table 1.

Example 4 The reaction and post-treatment were carried out using the same raw materials, amounts, and conditions as in Example 1, except that SLS2626 was replaced with IRG], 098. The results are shown in Table 1.

Example 5 Except for replacing SLS2626 with IRQMD1024,
The reaction and post-treatment were carried out using the same raw materials, amount of charge, and conditions as in Example 1. The results are shown in Table 1.

Example 6 The reaction and post-treatment were carried out using the same raw materials, amount of charge, and conditions as in Example 1, except that SLS2626 was replaced with T I N 1.44. The results are shown in Table 1.

Example 7 1.75.0 g of 10 wt% NaOH/methanol was added to 30
wt% OH/methanol 95.0g, 5LS262
6 Addition amount 0.1g to 0.2g, water added after reaction m20
The reaction and post-treatment were carried out using the same raw materials, charging nails, and conditions as in Example, except that 0- was replaced with 100 ml. The results are shown in Table 1.

Example 8 Reaction and aging temperature 40'C to 60°C, 5LS262
Example 1 except that the amount added was changed from 0.1g to 0.2g.
The reaction and post-treatment were carried out using the same raw materials, amounts, and conditions as in . The results are shown in Table 1.

Example 9 SLS2626 addition amount 0.1g was replaced with 0.2g, 10
The reaction and post-treatment were carried out using the same raw materials, amounts, and conditions as in Example 1, except that the base β-bromoethylbenzene was added dropwise to the wt% NaOH/methanol solution. The results are shown in Table 1.

Comparative Example 1 The reaction and post-treatment were carried out using the same raw materials, amounts, and conditions as in Example 1, except that 5LS2626 was replaced with P-phenylenediamine. The results are shown in Table 1.

Comparative Example 2 The reaction and post-treatment were carried out using the same raw materials, amounts, and conditions as in Example 1, except that SLS2626 was replaced with phenothiazine. The results are shown in Table 1.

Comparative Example 3 The reaction and post-treatment were carried out using the same raw materials, amounts, and conditions as in Example 1, except that SLS2626 was replaced with hydroquinone monomethylethyl. The results are shown in Table 1.

Comparative Example 4 The reaction and post-treatment were performed using the same raw materials, amount of charge, and conditions as in Example 1, except that SLS2626 was replaced with pt-butylcatechol. The results are shown in Table 1.

Comparative Example 5 The reaction and post-treatment were carried out using the same raw materials, amount of charge, and conditions as in Example 1, except that no polymerization inhibitor was used. The results are shown in Table 1.

Claims (1)

[Claims] In a method for producing a cyclic brominated styrene monomer by reacting cyclic brominated β-bromoethylbenzene with an alcoholic solution of an alkali metal hydroxide, a 3,5-di-t-butyl-4-hydroxyphenyl group is added to the molecule. A method for producing a cyclic brominated styrene monomer that inhibits polymerization and prevents coloring, the method comprising reacting in the presence of a compound having at least one of the following: