JP2016132656A - Method for producing dimethylaminoethyl acrylate and quaternary salt thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing dimethylamino acrylate and dimethylamino acrylate quaternary salt, in which the method does not have adverse effect on a polymer obtained by polymerizing dimethylaminoethyl acrylate or dimethylaminoethyl acrylate quaternary salt by controlling the content of vinyl oxyethyl acrylate that is an impurity present in dimethylaminoethyl acrylate and dimethylaminoethyl acrylate quaternary salt.SOLUTION: A method for producing dimethylaminoethyl acrylate comprises transesterification between an alkyl acrylate and dimethylaminoethyl alcohol containing 20 ppm or less of vinyloxy ethanol in the presence of a catalyst.SELECTED DRAWING: None

Description

  The present invention relates to dimethylaminoethyl acrylate (hereinafter sometimes abbreviated as DA) and dimethylamino by transesterification of alkyl acrylate and dimethylaminoethyl alcohol (hereinafter sometimes abbreviated as DMAE) in the presence of a catalyst. The present invention relates to a method for producing ethyl acrylate quaternary salt (hereinafter sometimes abbreviated as DA quaternary salt).

  A dialkylaminoethyl (meth) acrylate such as DA, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate or the like or a dialkylaminoethyl (meth) acrylate salt having the amino group as a tertiary or quaternary salt is used as a fiber dyeability improving agent, plastic As an antistatic agent, a pigment dispersant in paints, an ultraviolet curing aid, and polymers obtained by homopolymerization or copolymerization with other unsaturated compounds are fiber treatment agents, toner binders, paints, lubricant additives, Paper strength enhancers, adhesives, ion exchange resins, polymer flocculants and the like are used in a wide range of fields.

  A method for producing DA by transesterification of lower alkyl acrylate and DMAE is a known technique, and as a reaction catalyst, a tin compound such as alkali metal alcoholate, magnesium alcoholate, titanium alcoholate, dibutyltin oxide, or an acetylacetone metal complex compound such as acetylacetone iron, etc. The obtained DA can be purified by a normal distillation operation (Patent Documents 1 to 3).

Conventionally, as for impurities contained in DA, N, N′-dimethylpiperazine, ethylene glycol diacrylate and vinyloxyethyl acrylate are known in addition to the lower alkyl acrylate and dimethylaminoethyl alcohol which are raw materials. Among these, ethylene glycol diacrylate and vinyloxyethyl acrylate are known to cause quality problems such as the formation of gelated products during polymerization because they act as crosslinking agents when producing polymers. (Patent Document 4).
In particular, since vinyloxyethyl acrylate has a boiling point close to that of DA and is difficult to separate by rectification, it is a substance that is easily contained as an impurity in DA.

  However, Patent Document 4 does not mention how much ethylene glycol diacrylate and vinyloxyethyl acrylate are contained to adversely affect the polymer. Furthermore, there is no description of impurities in DA quaternary salts such as 2- (acryloyloxy) ethyltrimethylammonium chloride having DA as an ammonium salt and the influence of the impurities on the polymer.

JP 09-286765 A Japanese Patent Laid-Open No. 03-112949 Japanese Patent Laid-Open No. 02-229145 Japanese Patent Publication No. 2005-506958

  In view of the above situation, the object of the present invention is to control the upper limit of the content of vinyloxyethyl acrylate, which is an impurity of DA and DA quaternary salt, to obtain the weight obtained by polymerizing DA or DA quaternary salt. To provide a method for producing DA and DA quaternary salts that do not adversely affect coalescence.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have produced DA using DMAE in which vinyloxyethanol contained as an impurity in DMAE as a raw material is 20 ppm or less, thereby producing a crosslinking component. It has been found that a polymer or copolymer of DA and DA quaternary salt can be stably obtained without substantially including vinyloxyethyl acrylate as described above and without causing problems such as gelation.

  That is, the first invention of the present invention is the production of dimethylaminoethyl acrylate, characterized by transesterifying an alkyl acrylate and dimethylaminoethyl alcohol having a vinyloxyethanol content of 20 ppm or less in the presence of a catalyst. Is the method.

  The second invention of the present invention is a process for producing a dimethylaminoethyl acrylate quaternary salt, characterized in that the dimethylaminoethyl acrylate obtained by the process of claim 1 is quaternized with a quaternary chlorinating agent. .

  The third invention of the present invention is dimethylaminoethyl acrylate or a dimethylaminoethyl acrylate quaternary salt obtained by the method of any one of claims 1 and 2.

  Furthermore, a fourth invention of the present invention is a method for producing a polymer flocculant characterized in that the dimethylaminoethyl acrylate quaternary salt obtained by the method of claim 2 is used as a cationic monomer.

  The dimethylaminoethyl acrylate or the quaternary salt of dimethylaminoethyl acrylate obtained by the production method of the present invention can stably produce quaternary dimethylaminoethyl acrylate or dimethylaminoethyl acrylate without causing problems such as gelation during polymerization. A salt polymer or copolymer is obtained.

The present invention will be described in detail below.
The DMAE used in the present invention preferably has a purity of at least 99.9% by mass, in which case the content of impurities excluding water is 700 ppm or less, preferably 500 ppm or less, of which the content of vinyloxyethanol Is 20 ppm or less, preferably 10 ppm or less.

  The alkyl acrylate used in the present invention is, for example, an alcohol having 1 to 6 carbon atoms, such as methanol, ethanol, isopropanol, n-propanol, n-butanol, isobutanol, s-butanol, t-butanol. , N-pentanol or n-hexanol acrylate, preferably methanol, ethanol and n-butanol acrylate, and preferably n-butanol acrylate.

The transesterification catalyst used in the present invention is not particularly limited as long as it is a catalyst conventionally used in transesterification reactions. For example, tin compounds such as alkali metal alcoholates, magnesium alcoholates, titanium alcoholates, dibutyltin oxide, acetylacetone iron, etc. An acetylacetone metal complex compound or the like can be used.
The amount of the transesterification catalyst used is preferably an amount necessary so as not to deteriorate the productivity, and is preferably 0.1 to 10 mol%, more preferably 0.5 to 5 mol% with respect to DMAE. It is a range.
If the transesterification catalyst is added in a large amount, the reaction rate is improved accordingly. However, if the amount is too much, the effect of improving the reaction rate corresponding to the cost of the added catalyst is not recognized. As the method for charging the catalyst, either a method of charging at a time or a method of charging in a continuous or divided manner can be used, but a method of charging at a time when charging the raw materials is advantageous and preferable.

In the production method of the present invention, the reaction molar ratio of alkyl acrylate and DMAE is preferably 1.0 to 10.0 mol, more preferably 1.1 to 5. mol, with respect to 1.0 mol of DMAE. The range is 0 mol.
When the reaction molar ratio of alkyl acrylate and DMAE exceeds 10.0, a large reactor is required, and a large amount of energy is required to recycle excess alkyl acrylate, which is not preferable.

  The solvent used for the reaction is not usually required, but it is also possible to use, for example, xylene, toluene, hexane or the like as an azeotropic solvent for the by-produced alcohol.

Although the reaction temperature is affected by the raw material composition to be charged, it is almost determined by the degree of reduced pressure. The reaction temperature preferable for the present invention is 60 to 150 ° C., more preferably 90 to 120 ° C., and the reaction temperature is adjusted by adjusting the degree of vacuum. The corresponding preferred degree of vacuum is 200 to 500 Torr.
The reaction time depends on the reaction temperature, the amount of catalyst and the like, but is usually 4 to 5 hours.

It is preferable to add a polymerization inhibitor to the reaction system for the purpose of suppressing the thermal polymerization reaction during the reaction. Examples of the polymerization inhibitor include known ones such as hydroquinone monomethyl ether and phenothiazine, and one or more of these are used.
These polymerization inhibitors are preferably used in the range of 0.01 to 2.0% by mass, more preferably 0.05 to 1.0% by mass, based on the total charge.

After completion of the reaction, unreacted alkyl acrylate, DMAE, by-product alcohol, DA as the target compound, etc. are distilled from the reaction solution under reduced pressure. After removing the catalyst, a polymerization inhibitor is added to the distillate again. In addition, high-purity DA can be obtained by distillation by a conventional method.
The recovered catalyst can be used as it is for repeated reactions without any purification. However, since the viscosity tends to increase slightly as the number of repetitions increases, it was recovered from the viewpoint of industrial production stability. It is preferable to extract a part of the catalyst and add a new catalyst.
When removing the catalyst by distillation, there is almost no high-boiling point impurities, so it is possible to completely distill volatile components. However, considering the handling during reuse, 90 to 95% of the reaction end liquid is distilled. It is preferable to make it. It is desirable to avoid the reduction of the distillation rate because the productivity of DA decreases.

The polymerization inhibitor added during the re-distillation may be a known one, and examples thereof include hydroquinone, hydroquinomonomethyl ether and phenothiazine, and one or more of these are used.
These polymerization inhibitors are preferably used in an amount of 0.01 to 2.0% by mass, more preferably 0.05 to 1.0% by mass, based on the total charge.
The catalyst removal and DA purification steps are preferably performed at 130 ° C. or less from the viewpoint of suppressing the thermal polymerization reaction, and it is possible to use a heating medium such as silicone oil for the suppression of polymerization. Does not occur.

  Since the distillate distilled by the reaction of the present invention only contains a by-product alcohol and a small amount of alkyl acrylate, the distillate containing the by-product alcohol as a main component is directly reacted with, for example, acrylic acid. Then, alkyl acrylate can be easily obtained, and this alkyl acrylate can be recycled as a raw material of the present invention, and by-product alcohol can be effectively used.

As a method for quaternizing the DA produced by the above method, for example, a method described in JP-A-2003-342244 can be applied.
That is, a DA quaternizing agent produced from dimethylaminoethyl alcohol having a vinyloxyethanol content of 20 ppm or less as a raw material in a reactor charged with a dimethylaminoethyl acrylate (DA) quaternary salt aqueous solution as a reaction solvent; A dimethylaminoethyl acrylate quaternary salt having a low vinyloxyethanol content can be produced by continuously extracting the reaction solution in the reactor while continuously supplying water.

Examples of the quaternizing agent include alkyl halides such as methyl chloride and ethyl chloride, and arylalkyl hydrides such as benzyl chloride.
The ratio of the quaternizing agent to DA is preferably supplied to the reactor so as to be approximately equimolar, and the reaction temperature is preferably 30 ° C to 60 ° C.

  The DA quaternary salt obtained by the above method is used as a raw material for a cationic polymer and the like, and is used as a raw material for production of polymer flocculants, sludge dewatering agents, paper strength enhancers, antistatic agents, soil improvers, Used for applications.

  For example, a hydrated gel-like copolymer obtained by irradiating a mixed aqueous solution of DA quaternary salt and acrylamide with light from a chemical lamp in the presence of a photoinitiator is powdered produced using a grinder after drying with hot air A polymer can be used as a sludge dehydrating agent (for example, refer to JP 2011-224420 A).

Hereinafter, in order to describe the present invention more specifically, examples and comparative examples will be described in detail. The definitions of conversion, selectivity and yield used in this specification are as follows.
Conversion (%) = Mole of DMAE reacted / Mole of DMAE fed × 100
Yield (%) = DA moles produced / DMAE moles fed x 100
Selectivity (%) = yield / conversion rate × 100
Distillation yield (%) = distilled DA moles ÷ DA moles fed to distillation × 100
Overall yield (%) = yield (%) × distillation yield (%) / 100

Example 1
In a three-necked flask equipped with a rectifying column equipped with a stirrer, a thermometer, a condenser, and a fractionating column, DMAE 297 g (3.3 mol) containing 15 ppm vinyloxyethanol, n-butyl acrylate 1,280 g (10. 0 mol), 22.7 g (0.067 mol) of tetrabutyl titanate and 1.6 g (1,000 ppm) of phenothiazine as a polymerization inhibitor were added, and heating was started while stirring at 300 Torr under reduced pressure. After fully refluxing for 30 minutes, the reaction solution temperature was maintained at 110 to 120 ° C. and the top temperature of the rectifying column was maintained at 96 to 98 ° C., and n-butanol produced was withdrawn at a reflux ratio of 3.0 to 5.0. The reaction was performed for 4 hours.
When the reaction solution was analyzed by gas chromatography, the DMAE reaction rate was 92% and the DA yield was 90%.

Next, the catalyst was removed from this reaction solution at 30 Torr and 90 to 100 ° C. in a nitrogen atmosphere, and 1,296 g of a distillate containing DA was obtained. Further, 1.3 g of phenothiazine was added to the distillate, and then a rectification column (15 theoretical plates) equipped with a cooler and a fractionation column was used, under a nitrogen atmosphere, 20 Torr, 70 to 85 ° C., reflux ratio 1 After distilling off n-butanol, n-butyl acrylate and DMAE at 0.0-10.0, the same was distilled under a nitrogen atmosphere at 20 Torr, 85-95 ° C. and a reflux ratio of 1.0-2.0. 407 g was obtained. The overall yield of DA was 86% and the purity was 99.9%. When the reaction solution was analyzed by gas chromatography, vinyloxyethyl acrylate was not detected.
The obtained DA was converted into a quaternary ammonium salt (Example 2) by the method described later, and polymerization evaluation was performed. As a result of the polymerization evaluation, insoluble matter was not detected, and a high-quality polymer could be obtained.

Comparative Example 1
Except for using 297 g (3.3 mol) of DMAE containing 23 ppm of vinyloxyethanol, the same procedure as in Example 1 was carried out to obtain 400 g of DA. The overall yield of DA was 84%, and the purity was 99.9%. When the reaction solution was analyzed by gas chromatography, vinyloxyethyl acrylate was 12 ppm.
As a result of evaluating the polymerization of a quaternary ammonium salt (Comparative Example 2) in the same manner as in Example 1, 150 ml of insoluble matter was observed, and a high-quality polymer was not obtained.

Example 2
DA quaternization method 706 g of benzyl chloride was charged into a flask and heated to 30 ° C., then DA796 g prepared in Example 1 and 247 g of water were added dropwise over 5 hours, and then stirred and heated for 12 hours. Thereafter, 233 g of water was further added to produce a DA quaternary ammonium salt.

Comparative Example 2
A DA quaternary ammonium salt containing vinyloxyethanol was produced in the same manner as in Example 2 except that the DA produced in Comparative Example 1 was used.

Polymerization Evaluation Method DA quaternary ammonium salt produced in Example 2 and Comparative Example 2 and acrylamide were charged into a polymerization apparatus so that the mass ratio was 8: 2, and nitrogen desorption was performed for 1 hour while maintaining the liquid temperature at 10 ° C. After polymerization, 2,2′-azobis-2-amidinopropane dihydrochloride, which is a polymerization initiator, was added at 100 ppm to the monomer for polymerization.
The obtained pellet-like dried product of DA quaternary ammonium salt and acrylamide copolymer was added to water so as to be a 0.5 mass% aqueous solution, and stirred at 150 rpm for 3 hours to obtain an aqueous solution. The insoluble amount was determined by measuring the residual amount on the net when 400 ml of this aqueous solution was filtered with an 80 mesh stainless steel wire net in a water-containing state.

  When polymerizing DA or DA quaternary salt produced by the production method of the present invention, it is possible to stably obtain a good polymer, and in particular, the effect of contributing to the industry using sludge dewatering agent and polymer flocculant is It is a great thing.

Claims (4)

  A method for producing dimethylaminoethyl acrylate, comprising subjecting an alkyl acrylate and dimethylaminoethyl alcohol having a vinyloxyethanol content of 20 ppm or less to a transesterification reaction in the presence of a catalyst.   A method for producing a dimethylaminoethyl acrylate quaternary salt, characterized in that the dimethylaminoethyl acrylate obtained by the production method according to claim 1 is quaternized with a quaternary chlorinating agent.   A dimethylaminoethyl acrylate or a dimethylaminoethyl acrylate quaternary salt obtained by the method according to claim 1 or 2.   A method for producing a polymer flocculant, wherein the dimethylaminoethyl acrylate quaternary salt obtained by the method of claim 2 is used as a cationic monomer.