DE2159501A1 - Bis or tris-hydroxymethylamides of (meth)acrylic - acid prodn - by reacting corresp alkanolamine with (meth)acrylic acid - Google Patents

Abstract

Cpds. of formula: (in which R is CH3, C2H5 or HOCH2; and R1 is H or CH3) are produced by reacting (HOCH2)2C(R)NH2 with a lower alkyl (meth)acrylate in a molar ratio of 0.8-1.2:1, in the presence of Li or a Na- or K-alcoholate as a catalyst at 50-100 degrees C, pref. under a press. of 200 mm. Hg. to 1 atm. These cpds. are used in the prodn. of vinyloxazoline for mfre. of drying ribs, for protective coatings.

Description

Process for the preparation of bis- or trishydroxymethylamides Priority: December 9, 1970 in USA Serial No .: 96 591 The invention relates to a Process for the preparation of hydroxymethylamides. The invention is more particularly concerned with a process for the preparation of bis- or trishydroxymethylamides of acrylic acid or methacrylic acid.

U.S. Patent 2,831,858 describes vinyloxazolines made by Implementation of an amino alcohol, but limited to those that have the carbinol group have on the tertiary carbon atom to which alkyl and amino radicals are attached, with a low molecular weight alkyl ester of acrylic acid or methacrylic acid in the presence of Aluminum isopropylate can be produced. According to this patent specification is the use cannot be carried out by alkali alkoxide catalysts and promotes this Monohydroxymethylamide, which is undesirable was, and besides, is in This patent stated that aminoalkanediols and triols cannot be produced be.

it is therefore an object of this invention to provide a method of making from hydroxymethylamides.

Another object of the invention is to provide an improved method for the production of bis- and tris-hydroxymethylamides, for the production of protective coatings are suitable. Other objects of the invention will be apparent to those skilled in the art from the description apparently.

According to the invention, hydroxymethylamides of the general formula are used wherein R is a methyl, ethyl or hydroxymethyl group and R 'is a hydrogen atom or a methyl group, prepared in such a way that an alkanolamine of the general formula with a low molecular weight alkyl ester of acrylic acid or methacrylic acid in the presence of a catalyst and a polymerization inhibitor at reflux temperatures, thereby forming the amide. The amide is then filtered to remove solids such as catalyst and is then ready for most uses.

According to the present invention, the alkanolamine and the acrylic acid or methacrylic acid esters in a molar ratio of about 0.8 to 1.2 moles of alkanolamine mixed together per mole of ester. Preferably, however, the molar ratio is in the range of 0.9 to 1.1: 1, and a molar ratio of about 0.9: 1 is particularly preferred. A catalyst is added to the mixture in an amount from about 0.025 to 0.25 g per 100 g of the reactants are added, and a polymerization inhibitor is also used in an amount of about 0.05 to 0.1 g per 100 g of the reactants. The reaction mixture is then transferred to a reaction vessel equipped with a reflux condenser, one Heat source, a pressure reducing device and a take-off head is.

The mixture will, generally but not necessarily, be reduced Pressure, heated so that there is complete reflux until it is found that the alkanol part of the ester has separated. The reflux ratio is then preferably, but not necessarily, to about 3: 1 initially and then eventually adjusted to a total decrease, the alkanol and excess acrylic acid or methacrylic acid esters are separated from the reaction mixture.

The reaction mixture in the kettle is an alkanolamide according to the general formula where R and R 'have the above meaning.

The alkanolamide is then decanted or, preferably, not necessarily, filtered to remove insoluble material. The product is generally usable without further purification.

The alkanolamines suitable for the process of the invention are those in which there are three hydroxyalkyl groups on the carbon atom adjacent to the amino group or two hydroxyalkyl groups and one alkyl group, i.e. a methyl group or Ethyl group, are bonded. These alkanolamines are for example, but not exclusively, 2-amino-2-methyl-1,3-propanediol, 2-amino-2-methyl-1,3-propanediol and 2-amino-2-hydroxymethyl-1,3-propanediol. These latter compounds are preferred because they are commercially available and as the usual purity of the commercially available products suitable for the process according to the invention. However, other alkanolamines of the above definition are also possible suitable.

The esters suitable for the process according to the invention are, for example, but not exclusively, the methyl and ethyl esters of acrylic acid and methacrylic acid. These esters are commercially available and are of the commercial grade this Compounds is sufficient for the method according to the invention. The methyl ester is preferred for reasons of economy.

The catalysts suitable for the present invention are, for example Lithium metal or alkoxides of lithium, sodium or potassium. The alkoxides can the methoxides, ethoxides, propoxides or butoxides, the methoxides being preferred are. The particularly preferred catalyst is lithium metal, preferably in finely divided form Shape. The amount of catalyst used is generally in the range of about 0.025 up to 0.25 g / 100 g of the reactants. Generally about 0.025 g / 100 g is sufficient and therefore preferred. The polymerization inhibitor suitable for the process according to the invention can be any inhibitor known in the art, of which there are many, or be a mixture of these. Typical inhibitors include, but are not limited to, substituted catechols, 2,6-di-tert-butyl-4-methylphenol (such as Ionol from Shell Chemical Company) and substituted hydroquinones such as 2,5-di-tertiary-amylhydroquinone and 2,5-di-tertiary-butylhydroquinone. The invention is not, however, to a specific one Polymerization inhibitor limited.

The following examples serve to further illustrate the invention.

Example 1 119 g (1 mol) of 2-amino-2-ethyl-1,3-propanediol (AEPD) and 100 g (1 mole) of methyl methacrylate were placed in a 500 ml round bottom flask equipped with a stirrer, an air diffuser and a thermometer. 0.50 g Sodium methoxide and 0.50 g of di-tertiary amylhydroquinone (AHQ) were dispersed therein. Dry air was introduced below the surface of the liquid and the reaction mixture was heated at atmospheric pressure. The column head was adjusted so that a complete reflux occurred. At a vapor temperature of 65 0C and a liquid temperature from 950C, distillate removal began at a reflux ratio of 3: 1. To about 2 hours the liquid temperature was at 136 0C and the steam temperature increased to 670C. About 28 grams of distillate, mainly methanol, was collected. The reaction product in the flask was the amide of methacrylic acid and AEPD.

The amide was used to make a vinyl oxazoline that is useful in preparing drying oils as is known in the art.

Another 0.50 g of AHQ was added to the amide in the flask, and the pressure was reduced to less than 2 mm Hg. At a liquid temperature of 122 ° C. and a vapor temperature of 950 ° C., the reaction mixture began to distill.

After about 2 hours the liquid temperature was at 145 0C and the steam temperature has risen to 1240C The distillate, 127.3 g, possessed a neutralization equivalent of 169.58., The infrared spectrum was in agreement with the expected 2-isopropenyl-4-hydroxymethyl-4-ethyl-2-oxazoline.

The flask residue, 33.4 g, was polymerized material.

Example 2 Example 1 was carried out in all essential details repeated, but with the exception that 110 g (1.1 mol) and methyl methacrylate gn 0.1 g of lithium metal was used instead of sodium methoxide. The lithium was divided into five pieces of different dimensions. The AHQ was across from the 0.50 g used in Example 1 reduced to 0.10 g and the pressure was reduced to 300 mm Hg.

After about 90 minutes of heating, the liquid temperature was 90 Reached 0C and began to fall, and the steam had reached 500C and was falling on 360C. The distillate weighed 41.1 g.

The amide residue, 192.0 g, was poured off from the lithium catalyst. The amide had a neutralization equivalent of 841.57 and the infrared spectrum was in agreement with the expected amide.

A terpolymer was prepared from the amide and described in an emulsion paint is used. To a latex emulsion consisting of a mixture of Consisted of ethyl acrylate and methyl methacrylate in a weight ratio of 3: 2, 10% of the amide based on the weight of the acrylate solids was added. The three components were prepared according to conventional methods known in the art polymerized. The resulting Latex emulsion was made by dispersing Inorganic pigments are processed into an emulsion color. The color was applied to a wood substrate and showed excellent weather resistance.

If Example 2 with potassium methoxide instead of lithium metal or with 1.1 mol of methyl acrylate instead of methyl methacrylate or with 1.1 mol of ethyl acrylate was repeated instead of methyl methacrylate, the same good amide yields were obtained.

Example 3 A. The experiment of Example 2 was carried out in all essentials Details repeated, but with the exception that instead of methyl methacrylate (114 g, 1 mole) of ethyl methacrylate were used. The reaction mixture was at 300 mm Hg heated to 67 to 100C. The distillate, mainly ethanol, weighed 43.8 g and the residue, the amide, 196.9 g.

B. The above experiment was repeated except that on Instead of ethyl acrylate butyl methacrylate was used. During the first heating period however, no distillate was collected. 10 g of ethanol were added, and thereafter 10 g of distillate were collected. Solid polymers began to build up in the flask form, and the heating was stopped. The polymer was made as polymeric butyl methacrylate identified.

Example 4 The experiment of Example 1 was carried out in all western Details repeated, but with the exception that only 0.10 g AHQ was used, and that the sodium methoxide was replaced by 0.05 g of lithium metal, which was divided into several Pieces had been cut up. The first heating period was at 300 mm Hg carried out at 40 to 840C. 37.4 g of distillate were collected, with a 187.0 g of amide remained.

Example 5 The experiment of Example 4 was carried out in all essentials Details repeated, but with the exception that 105 g (1.05 moles) of methyl methacrylate was used and 3 ml of methanol was added. During the first heating period. the pressure was 200 mm Hg and the liquid temperature rose from 50 to 780 ° C. No air was blown in this example. 42.6 g of distillate were obtained and 189.2 g of residue with a neutralization equivalent of 635.88.

If in Example 5 the AEPD by 1 mole of 2-aminomethyl-1,3-propanediol or was replaced by 2-amino-2-hydroxymethyl-1,3-propanediol, was also obtained good yields of amide.

Claims (3)

Claims 1 Process for the preparation of bis- or tris-hydroxymethylamides of the general formula in which R is a methyl, ethyl or hydroxymethyl group and R 'is a hydrogen atom or a methyl group, characterized in that an alkanolamine of the general formula wherein R has the above meaning with a lower alkyl ester of acrylic acid or methacrylic acid in a molar ratio of 0.8 to 1.2: 1 in the presence of lithium metal, sodium alcoholate or potassium alcoholate as a catalyst and a polymerization inhibitor at a temperature of about 50 to 1000C. 2.) The method according to claim 1, characterized in that dB is used as Sodium alcoholate or potassium alcoholate, sodium or potassium methylate or ethylate used. 3.) Method according to claim 1 and 2, characterized in that, is reacted at a pressure in the range from 200 mm Hg to about 1 atm.