JP2002080424A - Method for producing hydroxyalkyl (meth)acrylate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a hydroxyalkyl (meth)acrylate by reacting (meth)acrylic acid with an alkylene oxide in the presence of a catalyst, wherein the catalyst gives such a high reaction rate as that of a conventional homogeneous catalyst, enhances the conversion rate of a reaction substrate, can easily be separated similarly to a case of a conventional heterogeneous catalyst, and gives high reaction selectivity. SOLUTION: This method for producing the hydroxyalkyl (meth)acrylate, characterized in that the catalyst is a polymer which contains a nitrogen atom and/or a sulfur atom in the molecule and can be dissolved in the reaction solution.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing hydroxyalkyl (meth) acrylate by reacting (meth) acrylic acid with alkylene oxide in the presence of a catalyst.

[0002]

2. Description of the Related Art A catalyst is usually used in producing hydroxyalkyl (meth) acrylate by reacting (meth) acrylic acid with an alkylene oxide. Conventionally studied or used as the above catalyst include chromium chloride, acetylacetone chromium,
Chromium compounds such as chromium formate, chromium acetate, chromium acrylate, chromium methacrylate, sodium dichromate, chromium dibutyldithiocarbamate, iron powder, iron chloride, iron formate, iron acetate, iron acrylate, iron methacrylate, etc. Compounds, trialkylamines, cyclic amines such as pyridine and nitrogen-containing compounds such as quaternary salts thereof, sulfides,
A homogeneous catalyst soluble in a reaction solution such as a sulfur-containing compound such as a sulfonium salt, and an insoluble resin insoluble in a reaction solution such as an anion exchange resin having an anion exchange group such as an amino group, a quaternary ammonium salt, or a pyridinium group. There is a homogeneous catalyst.

[0003]

The above-mentioned homogeneous catalyst is
The reaction proceeds with the reaction substrate and catalyst uniformly dispersed in the solution. Therefore, when a homogeneous catalyst is used, the reaction rate is high and the conversion rate of the reaction substrate is high. However, there has been a problem that the operation of separating the catalyst is difficult, and a waste liquid containing the catalyst is generated after the reaction, so that the waste liquid must be treated. On the other hand, the above heterogeneous catalyst is
Since the catalyst is insoluble in the reaction liquid, the operation of separating the catalyst is easy, and no waste liquid containing the catalyst is generated after the reaction.
In general, the reaction selectivity is higher than that of the homogeneous catalyst. However, a heterogeneous catalyst, for example, an ion exchange resin or the like, the reaction proceeds with a functional group immobilized on the carrier or the base surface as an active site, the reaction occurs on the catalyst surface, and therefore, There was a problem that the reaction rate was low and the conversion rate of the reaction substrate was low.

[0004] Accordingly, the problem to be solved by the present invention is that the reaction rate is high, the conversion rate of the reaction substrate is high, and the separation of the catalyst is difficult as in the conventional heterogeneous catalyst. It is to provide a catalyst which is easy to operate and has a high reaction selectivity.

[0005]

Means for Solving the Problems The present inventor has made intensive studies to solve the above-mentioned problems. As a result, they conceived of using a polymer soluble in a reaction solution as a catalyst, and found that the above problem could be solved when the polymer contained a specific component. That is, the method for producing a hydroxyalkyl (meth) acrylate according to the present invention is a method for producing a hydroxyalkyl (meth) acrylate by reacting (meth) acrylic acid with an alkylene oxide in the presence of a catalyst. , A nitrogen atom and / or a sulfur atom in the molecule and is soluble in the reaction solution.

[0006]

DETAILED DESCRIPTION OF THE INVENTION The amount of raw materials charged in the reaction of (meth) acrylic acid with alkylene oxide is (meth)
The preferred range is 1 mol or more of alkylene oxide per 1 mol of acrylic acid, more preferably 1.0 to 1.0 mol.
It is 5.0 mol, more preferably 1.0 to 3.0 mol, even more preferably 1.0 to 2.0 mol. When the charged amount of the alkylene oxide is less than 1.0 mol,
It is not preferable because the reaction rate decreases and the by-products increase. Further, if the charged amount of the alkylene oxide is too large, particularly if it exceeds 5 mol, it is not economically preferable.

[0007] (Meth) acrylic acid that can be used in the present invention means acrylic acid and methacrylic acid. The alkylene oxide that can be used in the present invention is preferably an alkylene oxide having 2 to 6 carbon atoms, more preferably an alkylene oxide having 2 to 4 carbon atoms, such as ethylene oxide, propylene oxide, and butylene oxide. Propylene oxide, particularly preferably ethylene oxide. The method for producing hydroxyalkyl (meth) acrylate according to the present invention is a method for producing hydroxyalkyl (meth) acrylate by reacting (meth) acrylic acid with an alkylene oxide in the presence of a catalyst, wherein the catalyst comprises nitrogen It is a polymer that contains atoms and / or sulfur atoms in the molecule and is soluble in the reaction solution.

The catalyst which can be used in the present invention is nitrogen, sulfur,
It is a polymer containing at least one atom selected from phosphorus, iron and chromium in the molecule, preferably a polymer containing a nitrogen atom and / or a sulfur atom in the molecule. For example, ethyleneimine, vinylpyrrolidone, dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, acrylonitrile, acrylamide, ethylene sulfide, styrenesulfonic acid, sulfoethylmaleimide, sulfoethyl (meth) acrylate, 3-allyloxy-2- A polymer obtained by polymerizing one or more monomers such as hydroxypropanesulfonic acid, vinylsulfonic acid and 2-acrylamido-2-methylpropanesulfonic acid, and a copolymer of styrene, ethylene, vinyl ether and divinyl ether. Examples thereof include those obtained by copolymerizing one or more polymerizable monomers with one or more of the above monomers.

[0009] The polymer as a catalyst that can be used in the present invention must be soluble in the reaction solution.
The weight average molecular weight is 500 to 10000000,
Preferably it is 1000-5,000,000, More preferably, it is 1000-200000. When the weight average molecular weight exceeds 10000000, the viscosity of the catalyst increases,
Separation of the reaction product from the catalyst becomes difficult. In particular,
For example, when mechanical separation such as filtration is performed, clogging of the filter agent is caused, and when separation is performed by distillation or the like, the bottom viscosity increases, which may cause clogging of a pipe or the like. When the weight average molecular weight is less than 500,
The boiling point of the reaction product becomes close to that of the reaction product, and if an attempt is made to separate the reaction product from the catalyst by distillation or the like, an operation such as rectification is required, and the process becomes complicated.

The polymer used as a catalyst in the present invention has a molecular weight distribution (Mw / Mn) of 1 to 50, preferably 1 to 30, and more preferably 1 to 10. Mw represents a weight average molecular weight, and Mn represents a number average molecular weight. When the molecular weight distribution exceeds 50, the number of molecules outside the above-mentioned preferred molecular weight range increases, and it becomes difficult to separate the reaction product from the catalyst. The catalyst that can be used in the present invention is preferably a non-crosslinked, chain polymer. The content of a nitrogen atom and / or a sulfur atom in a polymer as a catalyst usable in the present invention is 0.5 to 70%.
%, More preferably from 1 to 6% by weight.
0% by weight. Here, the “content of nitrogen and / or sulfur atoms in the polymer” refers to the total content of nitrogen and sulfur atoms contained in the polymer (only one of nitrogen and sulfur atoms) Means the content of one of them). This content is preferably as high as possible in terms of increasing the number of reaction active points, but if this content exceeds 70% by weight, the distance between the reaction active points becomes short, and even if the content is further increased, The number of active sites used effectively does not increase. On the other hand, if the content is 0.5% by weight or less, sufficient reaction activity cannot be obtained.

The amount of the polymer as a catalyst which can be used in the present invention is not particularly limited, but is preferably used in the range of 1 to 130% by weight, and more preferably 10 to 100% by weight based on the raw material (meth) acrylic acid. % Is more preferably used. In the present invention, the form of reaction between (meth) acrylic acid and alkylene oxide can be carried out according to a method generally used for this type of reaction. For example, when the reaction is performed in a batch system, the reaction is performed by introducing a liquid alkylene oxide into (meth) acrylic acid. The alkylene oxide may be introduced after dissolving (meth) acrylic acid in the solvent. At this time, the alkylene oxide may be added all at once, continuously or intermittently. And when adding continuously or intermittently,
As is often the case in this type of reaction, the reaction can be continued even after the introduction of the alkylene oxide, so-called ripening to complete the reaction. Further, it is not always necessary to initially charge (meth) acrylic acid at once, but it is also possible to divide into several parts and feed them.

When the reaction is carried out in a batch system, the catalyst comprises (meth) acrylic acid, hydroxyalkyl (meth)
It is preferable that the alkylene oxide is previously dissolved in an acrylate, a solvent or a mixture thereof, and then the alkylene oxide is introduced. Further, when (meth) acrylic acid is dividedly charged, a part of the catalyst may be dissolved in (meth) acrylic acid which is divided and charged, and then added together with (meth) acrylic acid.
When performing the reaction in a continuous manner, (meth) acrylic acid and liquid alkylene oxide are continuously charged into a tube-type or tank-type reactor, and the reaction solution is continuously withdrawn from the reactor. Will be In the case of these continuous reactions, a form in which a part of the reaction solution is circulated may be adopted.

When the reaction is carried out in a continuous manner, the catalyst is preferably dissolved in (meth) acrylic acid, hydroxyalkyl (meth) acrylate, a solvent or a mixture thereof in advance and then charged into the reactor. preferable. Raw material (meta)
Acrylic acid and the raw material alkylene oxide may be charged into the reactor from separate charging lines, respectively, or before being charged into the reactor, they may be previously mixed in a pipe, or a line mixer, a mixing tank, or the like. It may be put before. When the reactor outlet liquid is circulated to the reactor inlet, this liquid may be mixed with the raw material (meth) acrylic acid and the raw material alkylene oxide and then charged into the reactor. However, when (meth) acrylic acid and alkylene oxide are charged into the reaction solution from separate charging lines,
Since the molar ratio in the reaction solution becomes excessive (meth) acrylic acid in the vicinity of the inlet of (meth) acrylic acid, it is preferable to mix the respective raw materials in advance with pipes or the like before charging the reactor. It is good to put.

The reaction temperature is usually preferably in the range of 40 to 130 ° C., more preferably 50 to 100 ° C.
Range. If the reaction temperature is lower than 40 ° C., the progress of the reaction is slowed and the practical level is deviated. On the other hand, if the reaction temperature is higher than 130 ° C., the amount of by-products increases or the raw material (meth) is used. It is not preferable because polymerization of acrylic acid or hydroxyalkyl (meth) acrylate as a product occurs. In addition, the reaction may be performed in a solvent for the purpose of, for example, making the reaction proceed mildly. As the solvent, a general solvent such as toluene, xylene, heptane, and octane can be used. The pressure in the system at the time of the reaction depends on the type of raw materials used and the mixing ratio, but is generally performed under pressure.

In the reaction, a generally used polymerization inhibitor can be used. Examples of the polymerization inhibitor include hydroquinone, methylhydroquinone, tert-butylhydroquinone, and 2,6-di-t.
tert-butyl hydroquinone, 2,5-di-tert
-Butylhydroquinone, 2,4-dimethyl-6-te
phenol compounds such as rt-butylphenol and hydroquinone monomethyl ether; N-isopropyl-N ′
-Phenyl-para-phenylenediamine, N- (1,3
-Dimethylbutyl) -N'-phenyl-para-phenylenediamine, N- (1-methylheptyl) -N'-phenyl-para-phenylenediamine, N, N'-diphenyl-para-phenylenediamine, N, N ' Paraphenylenediamines such as di-2-naphthyl-para-phenylenediamine; amine compounds such as thiodiphenylamine and phenothiazine; copper dialkyldithiocarbamate such as copper dibutyldithiocarbamate, copper diethyldithiocarbamate and copper dimethyldithiocarbamate; nitroso Diphenylamine, isoamyl nitrite, N-nitroso-cyclohexylhydroxylamine, N-nitroso-
Nitroso compounds such as N-phenyl-N-hydroxylamine or a salt thereof; 2,2,4,4-tetramethylazetidine-1-oxyl, 2,2-dimethyl-4,4-dipropylazetidine-1- Oxyl, 2,2,5,5-tetramethylpyrrolidine-1-oxyl, 2,2,5,5
-Tetramethyl-3-oxopyrrolidine-1-oxyl, 2,2,6,6-tetramethylpiperidine-1-oxyl, 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl, 6 Aza-7,7-dimethyl-spiro (4,5) decane-6-oxyl, 2,
2,6,6-tetramethyl-4-acetoxypiperidine-1-oxyl, 2,2,6,6-tetramethyl-4-
Examples thereof include N-oxyl compounds such as benzoyloxypiperidine-1-oxyl. The addition amount of the polymerization inhibitor is preferably 0.0001 to 1% by weight, more preferably 0.001 to 0.5% by weight, based on the carboxylic acid.

In the case of recovering and reusing the catalyst used in the present invention, a method of separating the catalyst from the product by distillation, recovering the catalyst as a distillation bottom liquid, and reusing the catalyst in the reaction step, or other solvents. Is added, and the catalyst layer and the reaction solution layer are separated into two phases to recover the catalyst and reuse it for the reaction. In the production method of the present invention, the obtained crude hydroxyalkyl ester may be further purified, if necessary. The purification method is not particularly limited, and includes, for example, purification by distillation. More specifically, for example, distillation using a general-purpose distillation tower, a rectification tower such as a packed tower, a bubble bell tower, a perforated plate tower, or the like may be mentioned, but it is not particularly limited thereto. Further, other purification means may be used in combination with the distillation purification. In addition, at the time of purification, the above-mentioned polymerization inhibitor can be appropriately used.

[0017]

The present invention will now be described in detail with reference to Examples, but it should be understood that the present invention is by no means restricted to such specific Examples. Example 1 A gas in a 2 L autoclave equipped with a thermometer, a heating / cooling device, and a stirrer was replaced with a mixed gas adjusted to an oxygen concentration of 3% and a nitrogen concentration of 97%. 844 g of acrylic acid was charged into the autoclave, 2 g of phenothiazine as a polymerization inhibitor, 5 g of hydroquinone monomethyl ether, and polydimethylaminoethyl acrylate (weight average molecular weight = 100) as a catalyst.
00, molecular weight distribution = 10, nitrogen atom content in the polymer = 9.2% by weight). Next, the liquid temperature in the autoclave was raised to 70 ° C., which is the reaction temperature. Then, 620 g of ethylene oxide was supplied into the liquid in the autoclave at a substantially constant speed over about 4 hours through a pipe attached to the autoclave using a liquid sending pump. During this time, the reaction was maintained at 70 ° C. Thereafter, the reaction was continued for 1 hour while maintaining the temperature at 70 ° C.

When the reaction mixture was analyzed, the conversion of acrylic acid was 89% and the selectivity for dialkylene glycol monoacrylate (based on acrylic acid) was 4.0 mol%. Thereafter, unreacted ethylene oxide in the reaction solution was diffused under reduced pressure, and unreacted acrylic acid was separated by distillation. Subsequently, distillation was able to separate into a bottom solution (hydroxyethyl acrylate solution) containing the catalyst at a high concentration and hydroxyethyl acrylate containing substantially no catalyst.

[0019]

According to the present invention, in a method for producing hydroxyalkyl (meth) acrylate by reacting (meth) acrylic acid with an alkylene oxide in the presence of a catalyst, the reaction is carried out as in a conventional homogeneous catalyst. Speed is fast,
It is possible to provide a catalyst that has a high conversion ratio of a reaction substrate, is easy to separate the catalyst like a conventional heterogeneous catalyst, and has a high reaction selectivity.

Continued on front page F term (reference) 4G069 AA06 AA15 BA22A BA22B BE13A BE14B BE21A CB25 DA02 EC27 4H006 AA02 AC21 BA51 BA52 BN10 4H039 CA60 CF10

Claims (1)

[Claims] 1. A method for producing a hydroxyalkyl (meth) acrylate by reacting (meth) acrylic acid with an alkylene oxide in the presence of a catalyst, wherein the catalyst has a nitrogen atom and / or a sulfur atom as a molecule. And a polymer soluble in the reaction solution.