USE OF A TRIETHANOLAMINE PRODUCT MIXTURE

Abstract: Use of a triethanolamine product mixture in cosmetic products, cleaning compositions and functional fluids, the triethanolamine product mixture containing a major part of triethanolamine, a minor part of diethanolmono-C3-C4-alkanolamine and monoethanoldi-C3-C4-alkanolamine and less than 1 % by weight diethanolamine and monoethanolamine.

Description: USE OF A TRIETHANOLAMINE PRODUCT MIXTURE The present application relates to the use of a triethanol- amine product mixture having a low content of diethanolamine and monoethanolamine in functional fluids, such as lubricants, metal working fluids and hydraulic fluids. The use of triethanolamine in a variety of industrial fluids is well known. Triethanolamines are normally produced in one or more steps by ethoxylating ammonia with ethylene oxide. In order to avoid the formation of polyalkyleneglycol chains, HOC 2 H 4 (OC 2 H 4 ) n , where n > 0, and the nitrogen atom to be quater- nized the ethoxylation is normally stopped, when the reaction mixture contains 60-90% by weight of triethanolamine and 10-40% by weight of diethanolamine and monethanolamine. Such a reac¬ tion mixture may be subjected to distillation to obtain purer triethanolamine. The fact that the triethanolamine reaction product contains a large amount of diethanolamine has not previously been considered a real drawback, as diethanolamine contributes to anticorrosion properties low foaming and desired alkalinity when used in functional fluids. Recently, more attention has been paid to the fact the diethanolamine is toxic and forms nitrosamines, which are carcinogenic in animal tests. Therefore, a reduction of the content of diethanolamine is desirable. The content should according to recommentations be less than 1% by weight. Thus, one object of the invention is to produce a trietha¬ nolamine product mixture which contains diethanolamine in an amount less than 1% by weight. This triethanolamine product mixture shall at least have about the same corrosion inhibiting ability and/or defoaming properties in functional fluids. Another object of the invention is that the method of producing a triethanolamine product mixture shall be simple to perform and that the mixture shall be usable without any additional cleaning and/or working-up processes, such as destination. Still another object of the invention is to keep the forma¬ tion of quartemized triethanolamine and polyalkylene glycol chain containing ethanola ine products to a low level. According to the invention it has now been found that these objects can be met by using in functional fluids, a triethanol¬ amine mixture containing a major part of triethanolamine, a minor part of diethanolmono-C 3 . 4 -alkanolamine and monoethanoldi- Cg^-alkanolamine, and less than 1% by weight of diethanolamine and monoethanolamine. By the expression "major part of tri- ethanolamine" is here understood that said triethanolamine constitutes at least 50% by weight of the product mixture. The triethanol amine product mixture used in accordance with the invention can easily be obtained by reacting a conventional triethanolamine reaction mixture, obtained when reacting ammonia in one or more steps, with a C 3 -C 4 -alkylene oxide. Such a process is described in British Patent No 1 140 867. Diethanolamine and monoethanolamine which are both reactants in the process have a catalytic effect and catalyze rather selec¬ tively their own alkoxylation. The presence of an effective amount of alkoxylation catalyst other than the diethanolamine and monoethanolamine shall preferably be avoided in order not to favour undesired side reactions. By the process the contents of diethanolamine and monoethanolamine are reduced to less than 1% by weight, while the undesired side reactions, such as alkoxylation of hydroxyl groups or quarternization of the nitrogen atom is kept on a low level. In order to further suppress side reactions, it has been found suitable to perform the reaction below 160°C, preferably between 120-150°C. The amount of alkylene oxide added has to be adjusted in relation to the amount of diethanolamine and monoethanolamine, so that the latter ones can be alkoxylated to the corresponding ter¬ tiary amine. Normally, the molar ratio of the alkylene oxide to the reactive hydrogen atoms bound to the nitrogen in diethanol¬ amine and monoethanolamine is 1.0-1.4 and suitably 1.0-1.10. The choice of alkylene oxide affects the HLB-value of the triethanolamine mixture formed during the reaction and the butylene oxide may be preferred if a product mixture with the more hydrophobic and surface active character is desired. Normally, the alkylene oxide used is propylene oxide. Both propylene oxide and butylene oxides react with a high selec- tivity with respect to the hydrogen atoms bound to the nitrogen atom in the primary and secondary amine resulting in a lower degree of side reactions like propoxylation of hydroxyl groups in monoethanolamine, diethanolamine or triethanolamine. The triethanol amine product mixture used in accordance with the invention has many advantageous properties. Thus, application tests have clearly indicated that the triethanol¬ amine product mixture is very suitable to replace triethanol¬ amine as a component in aqueous functional fluids, such as lubricants, metal working fluids and hydraulic fluids. The diethanolmono-C 3 -C-alkanolamine in the triethanolamine product mixture contributes to improved corrosion inhibiting and low foaming properties. The present invention is further illustrated by the follow¬ ing examples. Example A. 100 grams of a triethanolamine product mixture containing 85% by weight of triethanolamine and 15% by weight of dietha¬ nolamine and monoethanolamine (hereinafter referred to as TEA85) were reached with 8,4 grams of propylene oxide at 60°C. The ratio between the molecules of propylene oxide and the number of hydrogen atoms bound to a nitrogen atom was 1,01. After all propylene oxide had reacted the product obtained (hereinafter referred to as TEA85+PO) was analyzed with respect to the presence of secondary and primary ethanolamines. The total content of these alkanolamines was found to be less than 0,5% by weight. Example B. 100 grams of the same triethanolamine product mixture as specified in Example A were reacted with 10,4 grams of butylene oxide at 70°C. The ratio between the molecules of butylene oxide and the number of hydrogen atoms bound to a nitrogen atom was 1,00. After reaction with product mixture obtained (here¬ inafter referred to as TEA85-B0) was analyzed and the content of secondary and primary alkanolamines was found to be 0,7% by weigh . Example C. 100 grams of the same triethanolamine products mixture as specified in Example A were reacted with 10.9 grams of propy¬ lene oxide at 150°C. The ratio between the molecules of propy¬ lene oxide and the number of hydrogen atoms bound to a nitrogen atom were 1.3. After reaction the content of secondary and primary alkanolamines was found to be less than 0.1% by weight. Example l. The trietanolamine product mixtures TEA85-PO and TEA85-BO from Examples A and B were diluted with water having a water hardness of 0,2°dH to solutions containing 1, 2 and 3% by weight. The solutions were then neutralized with acetic acid to a pH-value of 9. As comparisons corresponding solution was also formulated from the triethanolamine product mixture used as starting product in Example A (hereinafter referred to as TEA85) and a distillation product of TEA85 containing 99% by weight of triethanolamine. The latter product are hereinafter referred to as TEA99. The twelve solutions were then tested with regard to their Fe corrosion according to cast iron chip-on-filter paper test (IP 287) and copper corrosion. In the measuring of copper corrosion 0,2 grams of copper powder was mixed with 10 grams of glass beads in 200 ml of the solution containing the alkanol¬ amines. The solutions were shaked for 24, 48 and 72 hours and the content of copper in the solutions was determined. The following results were obtained. It is obvious that the alkanolamine product mixtures in accordance with the invention have favourable corrosion proper¬ ties in comparison with prior used alkanolamine products. Example 2. The solutions of Example 1 containing 3% by weight of the alkanolamines were also tested with regard to foaming. 200 ml of each solution was vigorously stirred during 5 minutes and the volume of the fluid and the foam was measured. The follow¬ ing results were obtained. ^ Volume of the solutions before stirring is 200 ml. From the results it is evident that the product mixtures of the invention has a low foaming like the prior art products. Example 3. Synthetic metal working fluid concentrates were prepared from 20 parts by weight of TEA85-P0 or TEA99, 25 parts by weight of dodecandioic acid, 55 parts by weight of distilled water and potassium hydroxide in an amount sufficient to give a pH of 9,8. The concentrates were then diluted with water having a water hardness of 200 ppm in accordance with the table below and tested with regard of foaming ability in accordance with Institute of Petroleum, IP 312 and with regard to iron corro¬ sion in the same manner as in Example 1. The following results were obtained. From the results it is evident that the triethanolamine product mixture of the invention with advantage can replace TEA99.

Claims: CLAIMS 1. Use of a triethanolamine product mixture in functional fluids, the triethanolamine product mixture containing a major part of triethanolamine, a minor part of diethanolmono-C 3 -C 4 - alkanolamine and monoethanoldi-C 3 -C 4 -alkanolamine and less than 1% by weight diethanolamine and monoethanolamine. 2. Use in accordance with claim 1, characterised in that the major part is 60-90% by weight, and the minor part is 10- 40% by weight. 3. Use of the triethanolamine product mixture of claim 1 or 2 in an aqueous metal working fluid.

Inventors: SKOELD ROLF, SKOELD, ROLF
Applicants: BEROL NOBEL AB
Application year: 1992
Main classification: C10M105
IPC codes: A61K8, A61Q19, C10M133, C10M173, C10N30, C10N40, C11D1, C11D3