JPH0222064B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing alkylaminoalkyl esters of acrylic acid or methacrylic acid by transesterification. Alkylaminoalkyl esters of acrylic acid or methacrylic acid are cationic polymer flocculants,
It is a useful material as a raw material for paper processing agents, fiber processing agents, etc. It is known to produce alkylaminoalkyl esters of acrylic acid or methacrylic acid by transesterification of lower alkyl esters of acrylic acid or methacrylic acid with alkylaminoalkanols, using alkali metal alcoholates, titanium alcoholates, aluminum as catalysts. It is known to use alcoholates such as alcoholates, organic tin compounds, lead compounds, thallium compounds, and the like. Among these catalysts, alkali metal alcoholates have the disadvantage that they tend to produce side-reactants and polymers, and their catalytic activity decreases over time during the reaction. Further, titanium alcoholate and aluminum alcoholate are expensive and have the disadvantage that the catalyst is deactivated by the influence of a small amount of moisture. Furthermore, as organic tin compounds, dibutyltin oxide and dioctyltin oxide are known, but they are not satisfactory because their catalytic activity is insufficient for industrial implementation. In addition, lead compounds and thallium compounds have complicated problems in their handling and treatment of waste catalysts due to their toxicity. As a result of our efforts to develop an excellent industrial catalyst that does not have these drawbacks, we have developed a catalyst with the general formula
It has been discovered that an organic tin compound represented by R ₃ Sn-OH (in the formula, R represents an alkyl group having 1 to 12 carbon atoms or a phenyl group) is an excellent catalyst with high activity and few side reactions. , we have completed the present invention. That is, the present invention provides a method for producing an alkylaminoalkyl ester of acrylic acid or methacrylic acid by a transesterification reaction between a lower alkyl ester of acrylic acid or methacrylic acid and an alkylamino alcohol.
This is a method for producing an alkylaminoalkyl ester of acrylic acid or methacrylic acid, characterized by using R ₃ Sn-OH (in the formula, R represents an alkyl group having 1 to 12 carbon atoms or a phenyl group). The raw material lower alkyl ester of acrylic acid or methacrylic acid used in the present invention is generally a lower alkyl ester having fewer carbon atoms than the raw material alcohol, preferably methyl or ethyl ester of acrylic acid or methacrylic acid. The raw material alkylamino alcohol used in the present invention has the general formula

[Formula] (wherein R ¹ represents a hydrogen atom or an alkyl group having 1 to 8 carbon atoms, R ² represents an alkyl group having 1 to 8 carbon atoms, and n has a value of 1 to 4) Alkylamino alcohols, suitable examples include methylaminoethanol, dimethylaminoethanol, ethylaminoethanol,
methylethylaminoethanol, diethylaminoethanol, diisopropylaminoethanol,
These include dibutylaminoethanol and tert-butylaminoethanol. Examples of catalysts used in the present invention include trimethyltin hydroxide, triethyltin hydroxide, tributyltin hydroxide, trioctyltin hydroxide, triphenyltin hydroxide, and the like. All of these catalysts have high activity, but triphenyltin hydroxide exhibits particularly high activity. The amount of catalyst used in the method of the present invention is 0.01 to 10 mol%, preferably 0.01 to 10 mol% based on the raw material alcohol.
It is 0.1 to 3 mol%. The amount of the lower alkyl ester of acrylic acid or methacrylic acid used as the raw material is in the range of 1.2 to 4 mol, preferably 1.5 to 2.5 mol, per 1 mol of the raw material alcohol. During the reaction, a polymerization inhibitor can be added to the reaction system to prevent polymerization of the raw material and the product ester. Polymerization inhibitors commonly used include:
Phenothiazine, hydroquinone, hydroquinone monomethyl ether, di-tert-butylcatechol, phenyl β-naphthylamine, paraphenylene diamine, etc. are used. Reaction temperature is 40-150
It can be carried out at a temperature of preferably 60 to 140°C. The reaction is usually carried out at normal pressure, but can also be carried out under reduced pressure or increased pressure if necessary. Although it is not necessary to use a solvent, it is possible to use one. When a solvent is used, the reaction can be carried out in the presence of an inert solvent that forms an azeotrope with the alcohol produced in the transesterification reaction, such as hexane, benzene, cyclohexane, and the like. Examples of the present invention are shown below, but it goes without saying that the scope of the present invention is not limited only to these Examples. In addition, the ester yield in the examples was determined by: ester yield=produced ester (mol)/raw material alcohol (mol)×100. Example 1 Methyl methacrylate 250.3 was added to a 1 liter flask equipped with a stirrer, a thermometer and a fractionating column.
g (2.5 mol), dimethylaminoethanol 89.1 g
(1.0 mol), triphenyltin hydroxide 3.67
(0.01 mol) and 2 g of phenothiazine were added and heated while stirring. The reaction was carried out for 4 hours while the mixture of methanol and methyl methacrylate azeotroped from the upper part of the fractionating column was continuously taken out of the system at a reflux ratio of 5 to 10. During this period, the fractionator top temperature was 63 to 68℃, and the pot temperature was 101 to 125℃.
It was warm at ℃. Analysis of the reaction solution thus obtained revealed that the conversion rate of dimethylaminoethanol was 100% and the yield of dimethylaminoethyl methacrylate was 98.6.
It was %. Pour this reaction solution as it is at 20-5 mmHg.
151.7 g (purity 99.9%) of a fraction of dimethylaminoethyl methacrylate having a temperature of 85 to 75°C was obtained. Ester yield is based on raw alcohol
It was 96.5%. Examples 2 to 4 Using the same equipment as in Example 1 and in the same manner,
The reaction was carried out by changing the raw material alcohol and/or the raw material ester. In each case, 1 mole of raw material alcohol and 2 moles of raw material ester were reacted, and the reaction was carried out by adding 1 mol % of triphenyltin hydroxide as a catalyst to the raw material alcohol and 2 g of phenothiazine as a polymerization inhibitor. The results obtained are shown in Table-1.

[Table] Comparative Example 1 A reaction was carried out in the same manner as in Example 1 using the same apparatus except that the catalyst was changed to diotyltin oxide. After reacting for 4 hours, the reaction solution was analyzed and the conversion rate of dimethylaminoethanol was 97.8%.
The yield of dimethylaminoethyl methacrylate was 95.4%. Use this reaction solution as it is for 20
146.2 g of dimethylaminoethyl methacrylate fraction (purity
99.9%). The ester yield was 93.0% based on the starting alcohol. The vacuum distillation residue of the reaction solution obtained in this reaction became extremely viscous and syrup-like. Example 5 (Catalyst activity test) 12.5 g (0.125 mol) of methyl methacrylate, 2.23 g (0.025 mol) of dimethylaminoethanol, and phenothiazine were placed in a 100 ml pressure-resistant glass ampoule tube.
0.088 g and 0.3 g of catalyst were charged, and after the tube was sealed, it was heated to 110°C to react. The container was opened at regular intervals, the reaction solution was analyzed, and the relationship between the reaction time and the yield of dimethylaminoethyl methacrylate relative to the charged dimethylaminoethanol was determined and plotted on the graph shown in FIG. 1 attached. As is clear from the results in FIG. 1, the catalyst of the present invention (triphenyltin hydroxide) shown by curve A has higher activity than the known catalyst (dioctyltin oxide) shown by curve B.

[Brief explanation of drawings]

FIG. 1 is a graph showing the relationship between the reaction time (hr) and the yield (%) of dimethylaminoethyl methacrylate relative to the charged dimethylaminoethanol in Example 5.

Claims (1)

[Claims] 1. In a method for producing an alkylaminoalkyl ester of acrylic acid or methacrylic acid by a transesterification reaction between a lower alkyl ester of acrylic acid or methacrylic acid and an alkylamino alcohol, a catalyst of the general formula R ₃ Sn-OH (wherein R is 1. A method for producing an alkylaminoalkyl ester of acrylic acid or methacrylic acid, which comprises using an organic tin compound represented by an alkyl group or phenyl group having 1 to 12 carbon atoms.