CS269400B1 - Aminocarboxylic acid amide - Google Patents

Abstract

Aminocarboxylic acid amides of the general formula I, intended for use in delicate laundry detergents and acidic cleaning agents. The amide is stable and surface-active over a wide pH range.

Description

The invention relates to aminocarboxylic acid amides useful as surfactants.

Commonly used amphoteric surfactants include carboxybetaines, sulfobetaines and aminocarboxylic acid derivatives.

Amphoteric surfactants based on amino acids are described in the comprehensive work Amphoteric Surfactants by B. R. Bluestein and C. L. Hilton. The surfactant prepared by the reaction of diethylaminopropylamine with maleic anhydride and dodecylamine exhibits, according to the authors, a very low threshold of irritation to the eyes and skin. The disadvantage of this type of surfactant is the presence of a secondary amino group, since its biological degradation can produce toxic nitrosamines.

The above disadvantages are not present in aminocarboxylic acid amides of the general formula IR ¹

RNHCOCH-— N —CH-CONH(CH-) — NI, ² I ^{2 2 n} 11

CH-COOH R ² 1 in which R denotes an alkyl radical with 8 to 22 carbon atoms, R denotes an alkyl radical with 1 to 3 carbon atoms and n is a natural number 2 to 3.

The prepared aminocarboxylic acid amides are surfactants usable in a wide range of pH values (from 2 to 12).

The preparation of aminocarboxylic acid amides is shown in the following examples.

Example 1

In a stirred reactor with a volume of 1,200 l, 275 kg of N,N-dimethylaminopropylamide of nitrilotriacetic acid are reacted in 152 kg of 1,2-propanediol and 186 kg of dodecylamine at a temperature of 160 °C for 6 h. During the reaction, the amount of primary amine is determined by titration. The reaction mixture is hydrolyzed with 100 kg of 40% sodium hydroxide at a temperature of 60 to 80 °C for 2 h and diluted with 360 kg of water. The obtained product was chromatographically separated by thin-layer chromatography in the system chloroformmethanol (95 : 5). In the main fraction (Ν,Ν-dimethylaminopropylamide dodecylamide of nitrilotriacetic acid) with a molecular weight of 430.8, total nitrogen (theory 13.01%, found 12.59%) and nitrogen after blocking the tertiary amino group (theory 6.50%, found 6.11%) were determined.

Example 2.

In a stainless steel autoclave, 102 kg of Ν,Ν-dimethylpropylenediamine is reacted with 191.5 kg of nitrilotriacetic acid in 138 kg of ethanol at a temperature of 140 °C and a pressure of 0.8 MPa. After the first stage has reacted, 214 kg of tetradecylamine is added and after 4 hours of reaction at 140 °C under normal pressure, the mixture is hydrolyzed with 187 kg of 30% potassium hydroxide solution at 50 °C for 1.5 hours. The solution is diluted with 1,030 kg of water. After separation by thin-layer chromatography and crystallization, elemental analysis revealed 63.2% carbon (theory 11.9%) and 10.4% hydrogen (theory 10.7%).

Example 3

102 kg of N,N-dimethylpropylenediamine and 152 kg of 1,2-propanediol are introduced into the reactor as in Example 1. 191 kg of nitrilotriacetic acid are stirred into the mixture at a temperature of 90 °C. After the reaction of the 1st stage (6 hours at a temperature of 165 °C and negative evidence for a primary amino group) 129 kg of octylamine are added and the mixture is reacted at 140 °C for 3 hours. Then 100 kg of 40% sodium hydroxide are hydrolyzed at a temperature of 60 °C and neutralized with citric acid to pH 5.5. The mixture is diluted to a 50% solution in 100 kg of water. Thin layer chromatography yielded an amide, the elemental analysis of which revealed 58.8% carbon (theory 59.1%), 14.1% nitrogen (theory 14.5%) and 9.5% hydrogen (theory 9.8%).

CS 269 400 Bl

A comparison of the surface tension of the prepared amides and the foaming properties of the amides according to Example 1 is given in the following tables.

Surface tension of aminocarboxylic acid amides

Conditions: active substance concentration 1.0 gl ^- ^ temperature 20 °C distilled water

Surface tension

surfactant according to example pH 4 /mN.m . PH 7 pH 10 1 27.2 27.6 27.5 2 35.6 36.4 36.0 3 26.8 27.2 27.3 Foaming capacity of aminocarboxylic acid amide according to example 1/ according to Ross· Conditions: Active substance concentration 1 g.l temperature 20 °C, hardness -Miles of water 0 foam height /mm/ at pH time (min.) 4 7 10 0 15.0 14.5 17.0 3 12.5 12.5 15.0 5 12.5 12.5 15.0 water hardness 20 °N, other conditions identical 0 18.0 8.0 14.0 3 15.0 6.5 11.5 5 15.0 6.5 11.5

The surfactant according to example 2 was compared with an anionic surfactant, which is generally used in detergent formulations. The washing ability of alkylbenzene sulfonates /ABS/ and alkanesulfonates is insufficient, especially in waters with a higher content of calcium ions. They are therefore combined with a high amount of complexing agents, so-called builders. The advantages of the new type of surfactant include the high washing efficiency of the active substance itself, which is demonstrated by the following table: /the efficiency was compared according to the methodology of the State Testing Institute No. 240/.

Concentration g al/Γ ¹

ABS surfactant according to example 1

1.0

1.0

Washing ability ΐ

H ₂ O dist.H hardness 1.783 mmol Ca2+/1

41.5 ·15.4

46,231.2

The surfactants from examples 1 and 3 also show comparable effectiveness in the alkaline range.

Claims (1)

SUBJECT OF THE INVENTION Aminocarboxylic acid amide of general formula I ť RNHCOCH5— N—CH—CONH(CH—) — NI, 4 1 íz n 1 CH,COOH'1 ZK in which R denotes an alkyl radical with 8 to 22 carbon atoms, R ¹ an alkyl radical with 1 to 3 carbon atoms and n a natural number of 2 to 3.