JP2870971B2 - Method for producing alkenylphenol - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for producing alkenylphenol.

More specifically, the present invention relates to a method for producing an alkenyl phenol by improving a method for charging an alkaline catalyst to a reaction system in a method for producing an alkenyl phenol by heating a dihydroxydiarylalkane in the presence of a basic catalyst.

[Conventional technology]

It is well known that heating a dihydroxydiarylalkane in the presence of a basic catalyst produces the corresponding phenols and the corresponding alkenylphenols. Various methods for producing alkenylphenol utilizing this reaction have also been proposed (for example, Japanese Patent Publication Nos. 38-1368, 50-50341, and 55/34).
-27108, JP-B-49-48319, JP-A-62-14
No. 8441).

In these methods, as the basic catalyst, an oxide, hydroxide or carbonate of an alkali metal or alkaline earth metal, for example, sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, calcium oxide and the like are used. Have been. In addition, alcoholates, phenolates, alkylcarboxylates and the like can be used. However, in these methods, the basic catalyst is actually used in the form of a solid in a mixture with the raw material.

In order to implement such a method industrially, it is very complicated to keep the supply amount of the basic catalyst to the reaction system constant.

That is, in the known method for producing alkenylphenol from dihydroxydiarylalkane in the presence of a basic catalyst, in order to carry out this industrially in a continuous manner, a reaction system of a basic catalyst is required. There is a need to improve the charging method.

[Problems to be solved by the invention]

The present inventors have carried out a number of studies on a continuous charging method of a catalyst in the continuous production of alkenylphenol. As a result, they found that the catalyst in the system was kept at a constant temperature by continuously supplying the reaction system with an aqueous solution, the reaction was constant, and the product could be taken out at a constant flow rate. However, in general, the reaction is carried out at a high reaction temperature of 150 to 300 ° C. and under a reduced pressure of 5 to 100 mmHg in order to take out alkenylphenol as a monomer. If so, problems such as solidification of the catalyst near the charging inlet have occurred. Moreover, since the amount of charging is small, the amount of evaporation of water is large compared to the flow rate, so that the clogging phenomenon occurs quite frequently, which has been a problem.

In order to solve this problem, Japanese Patent Application Laid-Open No. 62-148441 proposes that a basic catalyst be used as an aqueous solution, mixed with dihydroxydiarylalkane, and charged into a reaction system. By charging the basic catalyst by this method, the problem of solidification of the catalyst near the charging inlet could be solved, but an operation of mixing the basic catalyst and dihydroxydiarylalkane was required, and alkenylphenol was known. Later operation becomes complicated when taking out by the above method.

An object of the present invention is to solve such problems and to provide a continuous method for producing alkenyl phenol which can perform a stable operation and does not require an operation of mixing an aqueous basic catalyst solution with another substance. is there.

[Means for solving the problem]

The present inventors have further eagerly studied a continuous supply method of a catalyst in the method for continuously producing a corresponding alkenylphenol by continuously heating a dihydroxydiarylalkane as described above, and completed the present invention. It is a thing.

That is, in a method for producing a corresponding alkenyl phenol by heating a dihydroxydiaryl alkane in the presence of a basic catalyst, an alkenyl phenol characterized in that a small amount of steam is simultaneously blown when an aqueous basic catalyst solution is charged. It is a manufacturing method.

The dihydroxydiarylalkane used in the method of the present invention may be substituted with a phenyl group and has 2 to 2 carbon atoms.
7 is a gem-diphenylolated product of an aliphatic hydrocarbon or an alicyclic hydrocarbon, and the phenylol group may be substituted with an alkyl group or an alkoxy group having 1 to 4 carbon atoms, a halogen atom, or the like. Examples of these diphenylol alkanes include 2,2- (4,4'-dihydroxydiphenyl) propane, 2,-(4, -hydroxyphenyl) -2- (2'-hydroxyphenyl) propane, 2- (4,4'-dihydroxy-3,3'-dimethyldiphenyl) propane, 2,2- (4,4'-dihydroxy-3
-Methyldiphenyl) propane, 1,1- (4,4'-dihydroxydiphenyl) ethane, 1,1- (4,4'-dihydroxydiphenyl) propane, 1,1- (4,4'-dihydroxydiphenyl) butane , 2,2 (4,4'-dihydroxydiphenyl) -3-methylbutane, 1,1- (4,4'-dihydroxydiphenyl) -2-methylpropane, 1,1- (4,4'-
Dihydroxydiphenyl) cyclohexane, 1,1,1-
(4,4'-dihydroxytriphenyl) ethane, 2,2-
(2,2'-dihydroxy-4,4'-di-t-butyldiphenyl) propane and the like.

These dihydroxydiarylalkanes are obtained by reacting phenols with carbonyl compounds. The dihydroxydiarylalkane used is not only a high-purity dihydroxydiarylalkane but also a reaction product when the dihydroxydiarylalkane is produced. It is also possible to use those containing a tar-like substance. Distilled residues in the step of purifying dihydroxydiarylalkanes, crystallization mother liquor concentrates, and the like containing these by-products can be directly applied to the method of the present invention. .

The above-mentioned dihydroxydiarylalkanes or by-products during the production and purification thereof produce the corresponding phenols and alkenylphenols by the method of the present invention.

The basic catalyst used in the method of the present invention includes oxides, hydroxides or carbonates of alkali metals or alkaline earth metals, for example, sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, calcium oxide. , Calcium hydroxide and the like are used. In addition, a phenolate, an alcoholate, an organic acid salt and the like can be used, but it is preferable to use an aqueous solution.

The amount of the catalyst used is suitably in the range of 0.01 to 5% by weight based on the reaction medium. The aqueous solution here may be a solution in which a basic catalyst is completely dissolved or an aqueous solution containing a partially undissolved one in a suspended state.

The amount of water used is not particularly limited. However, if the amount is too large, the operation of the reaction, particularly the operation of reducing the pressure, becomes difficult.

The trace amount of steam used in the present invention is not particularly limited,
The amount may not be enough to greatly reduce the concentration of the basic catalyst aqueous solution, but may be a very small amount. If a large amount of steam is charged, it becomes difficult to carry out the reaction operation, particularly the pressure reduction operation. It is desirable that the position where the steam is blown is as close as possible to the charging port.

The method of the present invention can be carried out in a batch system or a continuous system, but a great effect is obtained particularly in a continuous reaction system.

〔Example〕

 Hereinafter, the present invention will be described specifically with reference to examples.

Example 1 A distillation residue of bisphenol A in a step of producing bisphenol A from phenol and acetone was put into a reactor at 1000.
continuously charged in kg / hr, a 25% aqueous sodium hydroxide solution over another charging hole when loaded with 5 kg / hr, spout vicinity of the charging pipe steam 2 kg / hr of 2 kg / cm ² And the aqueous solution and steam were simultaneously charged. Continuously operated at 200 ° C and 50mmHg, distillate was collected from the upper part of the reactor at 607kg / hr, and 400kg / hr from the lower part.
Tar-like substances were continuously extracted at hr.

 Under these conditions, continuous operation for 6 months was possible.

Distillation residue composition: bisphenol A 30%, trisphenol 15%, other high-boiling substances 55% Distillate composition: phenol 41%, p-isopropenylphenol 27%, p-isopropenylphenol dimer 31
%, Others 1% Example 2 A decomposition reaction was carried out in the same manner as in Example 1 except that the distillation residue of bisphenol A in the step of producing bisphenol A from phenol and acetone was changed to bisphenol A. Distillate from upper part of reactor at 951kg / hr, 49kg / hr from lower part
Then, the tar-like substance was continuously extracted.

The composition of the obtained distillate was 43% phenol, 13% p-isopropenylphenol, 6% p-isopropenylphenol dimer, 2% bisphenol A, and 34% oligomers of trimer or more of p-isopropenylphenol. , And 2%.

 Under these conditions, one month of operation was possible.

COMPARATIVE EXAMPLE 1 When charging a 25% aqueous sodium hydroxide solution under the same conditions as in Example 1, no steam was added. During the operation for one week, the inlet of the aqueous sodium hydroxide solution was solidified, and the operation became impossible.

〔The invention's effect〕

The present invention relates to a method for producing an alkenylphenol, in which a basic catalyst essential for the reaction is stably supplied to the reaction system, and there is no trouble in the reaction operation or the reaction apparatus, and the method for producing the alkenylphenol continuously and stably. To provide. The industrial contribution is very large.

Claims (1)

(57) [Claims] 1. A method for producing a corresponding alkenylphenol by heating a dihydroxydiarylalkane in the presence of a basic catalyst, wherein a small amount of steam is simultaneously blown in when charging the aqueous solution of the basic catalyst. A method for producing an alkenylphenol.