CS232184B1 - Salts of 2-dimethylaminomotylphenol and its derivatives with aromatic hydroxycarboxylic acids - Google Patents

Abstract

The invention relates to the field of synthetic resins. The technical problem of preparing a suitable type of reactive salts, suitable for application, for example, as hardeners of epoxy resins, is solved. The essence of the invention are salts of Mannich bases, prepared from formaldehyde, dimethylamine and phenols, with aromatic mono- or dihydroxycarboxylic acids. The invention can be used primarily in the field of processing epoxy resins.

Description

(54) Salts of 2-dimethylaminomethylphenol and its derivatives with aromatic hydroxycarboxylic acids

The invention relates to the field of synthetic resins. The technical problem of preparing a suitable type of reactive salts, suitable for application, for example, as hardeners of epoxy resins, is solved. The essence of the invention are salts of Mannich bases, prepared from formaldehyde, dimethylamine and phenols, with aromatic mono- or dihydroxycarboxylic acids. The invention can be used primarily in the field of processing epoxy resins.

usually used as hardeners and accelerators for epoxy curing

Salts of tertiary amines with inorganic and carboxylic acids find countless applications in various fields of technology. One of the important groups of salts are salts of cyclic tertiary amines, prepared by condensation of phenols, aldehydes and primary or secondary amines. These tertiary amines, known as Mannich bases, easily form salts with hydrochloric, sulfuric, phosphoric and fluoroboric acids. Salts of 2 _> 4,6-(dimethylaminomethyl)phenol with lower aliphatic carboxylic acids, especially with acetic, propionic and 2-ethylhexanoic acids, are also known. These salts find application primarily as special hardeners of epoxy resins with a long latency period at room temperature.

A new series of salts of 2-dimethylaminomethyl phenol and its derivatives with aromatic hydroxy/carboxylic acids has now been prepared, of the general formula

GH

R.

•oh my god

OH in which R _x is H, -CH ₂ fa(CH ₃ ) ₂ or -CiyKCILj)^ , R^ is H, ~CH ₂ fe(CH ₃ ) _2> -CH^Hr(BH ₃ *

232,184

'1 or

R2 is H or OH,

R^ is H, CH, alkyl - C^^ or CH ₃ O- _z n is 1/4.

/

Mannich bases for salts according to the invention are prepared by the reaction of formaldehyde and dimethylamine with phenol, cresols, xylenes, low molecular weight novolak resins, isomeric dihydroxydiphenylmethanes and dihydroxydiphenylpropanes. Depending on the ratio of reactants, there may be one or a maximum of four groups in the Mannich base molecule - CHgEKCHj) ₂ « Mannich bases from other aldehydes and other dialkylamines do not provide the necessary reactive parameters in the form of salts, for example when curing epoxy resins. In the salts according to the invention, the reactivity is determined by the nitrogen content (amine number) and the content of carboxyl groups (acid number); other parameters (refractive index, SiíŽ* ation, color, viscosity) are less important and. insignificant from the point of view of assessing reactivity.

The salts of the invention are prepared by mixing the base with the carboxylic acid and thoroughly homogenizing, if necessary in the presence of a solvent. The salts of the invention are usually viscous liquids, sometimes with a certain proportion of crystalline phase. They are used in the form of a liquid or a solution in oxygen-containing solvents, for example as curing components of epoxy resins.

Example 1

By condensing 1 mole of phenol, 3.1 moles of dimethylamine (48% aqueous solution) and 3.1 moles of a 40% aqueous formaldehyde solution,

232 184 prepares Mannich base 2,4,6-(dimethylaminomethyl)phenol with a purity of 99.3% for GLC analysis. 1 mol (265 g) of 2,4,6-(dimethylaminomethyl)phenol is mixed and finely triturated with 3 mol of finely triturated aromatic hydroxycarboxylic acid, thereby obtaining the corresponding salt:

arom.

hydroxy- carboxy. acid weighings (g) amine number (mg KOH/g) calculated found acid number (mg KCH/g) calculated found salicylic acid 414.3 247.65 245.3 247.65 248.1 2,4-hydroxy- benzoic 462.4 231.29 229.1 23.1,29 232.3 2,5-dihydroxyphenylacetic acid 504.2 218.73 216.7 218.73 219.0 4-hydroxybenzoic 414.3 247.65 245.2 247.65 248.8 2-hydroxy-l- naphthoic 564.6 202.81 200.5 202.81 20273 2-hydroxy- phenylacetic acid 456.4 233.21 231.0 233.21 234.5 4-methyl-2- z hydroxybenz00^456.4 233.21 231.2 233.21 233.3 4-Methoxy-2-hydroxybezooré 504.4 216.8 218.78 21It9

Example 2

Claims (1)

270 g of 2,4,6- (dimethylaminomethyl) phenol with a purity of 98,2J% (depending on the nitrogen content) are mixed with 1 mol (36 µg) of industrial anacardic acid with an acid number of 153,5 mg KOH / g. homogenization gave a viscous liquid salt having an amine number of 264.9 mg KCH / g (theory 276.01 mg KOH / g) and an acid number of 89.2 mg. KOH / g (theory 92.00 mg KOH / g) .Technical anacardic acid is obtained from an extracting acuite oil. four hydroxycarboxylic acids differing in the number of double bonds in the alkyl. Example 3 By reaction of 1 mole of 2,2'-bis- (4-iydroxyphenyl) propane with 2.05 mole of a 50% aqueous dimethylamine solution and 2.05 mole of a 40% aqueous formaldehyde solution, 2,2'-bis (2-dimethylaminomethyl-1-4) is prepared. 986% .336.5 [mu] g (1 mol) of this base is dissolved in 100% ethanol (96%) and 27 [mu] g of salicylic acid is added with stirring. KOH / g (184.97 mg KOH / g theory) and an acid number of 183.8 mg KOH / g (184.97 mg KOH / g theory). THE INVENTION MUST BE INVENTED Salts of 2-dimethylaminomethylphenol and its derivatives with aromatic hydrocarboxylic acids of general formula CH ₂ fe (CH ₃ ) ₂ wherein is