JPS6221775B2 - - Google Patents

Description

[Detailed description of the invention]

The subject of the present invention is a process for the preparation of novel high-viscosity neutral complex esters of polyols and polymeric fatty acids and aliphatic monocarboxylic acids. Synthetic esters, so-called ester oils, have recently come to be used in increasingly large amounts as expensive lubricating oils. Thus, for example, diesters of dibasic carboxylic acids and monohydric alcohols, such as dioctyl sebacate or dinonyl adipate, or esters of polyols and monobasic acids, such as trimethylolpropane tripelargonate, are used as lubricants for aircraft turbines. It is proposed as. Recently, so-called complex esters have also been developed for this type of lubrication. The complex esters contain as esterification components, in addition to polyhydric alcohols such as trimethylolpropane or neopentyl glycol, monobasic carboxylic acids having 6 to 10 carbon atoms and dibasic acids such as sebacic acid or azelaic acid.
The good suitability of synthetic esters as lubricants is due to
This is due to the fact that the synthetic ester has a more favorable viscosity-temperature relationship than conventional lubricating oils based on mineral oils, and its freezing point is clearly lower when the viscosity is adjusted to be comparable. However, for many fields of use, new high viscosity automatic transmission fluids are required, for example with viscosity values of at least 14 cSt at 99°C (210°) or up to 150,000 cP at -26°C (-15°). Automatic transmission oil 80W for various fields
-90 (US Military Specification Mil-L-
2105c), the known synthetic esters are not suitable due to their limited viscosity. Lubricating oils of sufficient viscosity based on mineral oils are produced by adding polymers, such as styrene-butadiene copolymers (DE 1811516). A disadvantage of adding polymers to increase the viscosity of automatic transmission oils is that the shear of the polymer increases. This significantly reduces the viscosity of the corresponding oil by shearing, ie by plastic destruction of the polymer. Therefore, synthetic esters which, in addition to lower freezing points, have high viscosities and good viscosity-temperature relationships (high viscosity index) have become extremely important. By the way, a 2-4 primary hydroxy groups and 4-4 carbon atoms
a branched aliphatic polyhydric alcohol having 10 b dimer and/or trimer fatty acids produced by polymerizing unsaturated fatty acids having 16 to 18 carbon atoms, and c 6 to 16 carbon atoms Straight-chain or branched saturated aliphatic monocarboxylic acids, the amount of hydroxy groups esterified by the monocarboxylic acid being 50
It has been found that a new neutral complex ester consisting of (~90%) satisfies the abovementioned requirements to a degree hitherto unachievable. High viscosity neutral complex esters according to the invention include all branched aliphatic polyols containing 2 to 4 primary hydroxyl groups and 4 to 10 carbon atoms as alcohol component, such as neopentyl glycol, trimethylolethane, trimethyl Methylolpropane or pentaerythritol is present. Particular preference is given here to the trihydric alcohol trimethylolpropane. The polymeric fatty acids used are mixtures of dimer and trimer fatty acids produced by polymerizing unsaturated fatty acids having 16 to 18 carbon atoms. In this case, the mixture preferably contains 75% by weight or more of dimmer fatty acids. This polymeric fatty acid mixture may be prepared, for example, from an unsaturated fatty acid, such as oil acid, linoleic acid or linolenic acid, or from a fatty acid mixture containing unsaturated fatty acids, such as soybean oil or tallow oil, in a small amount of water at a temperature of about 200-300°C. and by thermal polymerization in the presence of mineral catalysts such as montmorillonite. The monocarboxylic acid component of the neutral complex esters according to the invention may consist of linear or branched saturated aliphatic monocarboxylic acids having from 6 to 16 carbon atoms. Mention may be made, for example, of caproic acid, caprylic acid, capric acid, lauric acid, myristic acid or palmitic acid as well as mixtures thereof. In this case, for example, in the distillation of coconut oil fatty acids, the precursor fatty acids
Particularly preferred are mixtures of fatty acids having 6 to 12 carbon atoms. Among branched monocarboxylic acids, the number of carbon atoms is 12 or more, which is branched at the α-position to the carboxyl group.
16 carboxylic acids are particularly preferred. This type of carboxylic acid can be produced, for example, by subjecting an unbranched saturated alcohol of average chain length to a Guerbet reaction and then oxidizing the resulting alcohol, which is branched at the 2-position and has an equal total number of carbon atoms. The isopalmitic acid prepared in this way by oxidizing 2-hexyldecanol is used as the monocarboxylic acid component of the complex ester according to the invention. Complex esters according to the invention consisting of a branched aliphatic polyol containing 2 to 4 primary hydroxy groups, a polymeric, in fact dimer, fatty acid and a linear or branched saturated aliphatic monocarboxylic acid, It can be prepared in known esterification methods by heating the reactants (to 200 DEG C. in a nitrogen atmosphere) using esterification catalysts such as tin powder, p-toluolsulfonic acid or others. Esterification can also be carried out in two steps. In this case, the alcohol component is first reacted with the dimer fatty acid, and after the partial reaction is completed, it is further esterified with a monocarboxylic acid. To purify the esterification product, it is treated with the addition of 1 to 5% by weight of activated bleaching earth. Any free monocarboxylic acid that may still be present is removed by distillation, thereby producing a complex ester with an acid number below 0.3. Owing to their excellent properties, namely high viscosity, low freezing point and favorable viscosity-temperature relationship, the neutral complex esters according to the invention are particularly suitable for use as lubricants for the lubrication of automatic transmissions and two-stroke engines. The complex esters according to the invention may be present as the sole base oil in the final lubricant or may be mixed as a blend component with other products already known for this purpose. When used as mixed components in lubricants and automatic transmission oils, they can be mixed in any quantitative ratio, which is determined solely by the required properties, such as viscosity, freezing point, viscosity-temperature relationship. However, in general the content of complex esters in the final product does not fall below 10-30% by weight.
Various additives such as antioxidants and anticorrosion agents, dispersants, high pressure additives, defoamers, metal deactivators and
Other additives suitable for use in the preparation of synthetic ester-based lubricants may also be added in conventionally effective amounts. Next, the object of the present invention will be explained in detail based on examples, but the present invention is not limited thereto. Example Production of neutral complex ester 268g (2 mol) of trimethylolpropane, 565g (approx. 1 mol) of dimerized fatty acid (approximately 95 g of dimerized fatty acid)
% by weight, a mixture consisting of about 4% by weight of trimerized fatty acids and about 1% by weight of non-polymerized unsaturated fatty acids) and
632 g (approximately 4 moles) of C ₆ to C ₁₂ fatty acids (approximately 5% by weight of C ₆ - fatty acids, approximately 4% C ₈ - fatty acids, and approximately 4% C ₁₀ - fatty acids by weight, as obtained by distillation of coconut oil fatty acids)
45% by weight and about 5% by weight of C ₁₂ -fatty acids) under nitrogen as carrier gas in a dehydrator.
Heated to 200°C. A mixture of tin powder and p-toluolsulfonic acid was used as the esterification catalyst. At the end of the reaction, further esterification was carried out at the same temperature but at reduced pressure (approximately 70 mmHg). After cooling to 120°C, 1.5 g (approximately 1% by weight) of activated bleaching earth was added, the mixture was heated again to 200°C, and excess monocarboxylic acid was distilled off in vacuo. The acid value of esterified product A (component 67% esterified with monocarboxylic acid) is
It was 0.28. The product is at 37.8℃ (=100〓)
It has a viscosity of 628 cSt and 57 cSt at 99°C (=210〓). The viscosity index is 164 and the freezing point is -38°C. The following complex esters, summarized in Table 1, were prepared according to the method described above.

【table】

【table】

Claims (1)

[Claims] 1 2 to 4 primary hydroxy groups and 4 to 4 carbon atoms
Dimers obtained by polymerizing a branched aliphatic polyhydric alcohol having 10 carbon atoms with an unsaturated fatty acid having 16 to 18 carbon atoms in an amount such that 10 to 50% of the hydroxyl groups present are esterified. / or trimer fatty acids and 50-90% of the hydroxy groups present
is esterified with a linear or branched saturated aliphatic monocarboxylic acid having from 6 to 16 carbon atoms in the presence of tin powder and/or p-toluolsulfonic acid until complete esterification. Heated to 200°C under nitrogen, the esterification was carried out initially under normal pressure and at the end of the reaction reduced to about 70 mmHg, and finally by bleaching with bleaching earth and removing the excess monocarboxylic acid present in vacuo. A method for producing a highly viscous neutral complex ester, which is characterized by removal by distillation. 2. The method according to claim 1, wherein the polyol component is trimethylolpropane. 3. The method according to claim 1 or 2, wherein the polymeric fatty acid component contains 75% or more of dimmer fatty acid. 4. The method according to any one of claims 1 to 3, wherein the monocarboxylic acid component is a mixture of fatty acids having 6 to 12 carbon atoms. 5. The method according to any one of claims 1 to 4, wherein the monocarboxylic acid component is a mixture of precursor fatty acids obtained during distillation of castor oil fatty acids. 6 The monocarboxylic acid component is branched at the α-position relative to the carboxyl group, and has 12 to 16 carbon atoms.
Claim 1 which is a saturated monocarboxylic acid of
The method described in any one of paragraphs to paragraphs 3 to 3. 7. Claim 1, wherein the monocarboxylic acid component is isopalmitic acid produced by oxidation of 2-hexyl-decanol resulting from Guerbet synthesis.
The method according to any one of paragraphs 2, 3, and 6.