HIGH MOLECULAR WEIGHT LIQUID ESTERS

Abstract: High molecular weight liquid esters can be prepared by reacting primary branched alcohols with polymeric fatty acids to produce liquid esters. The primary branched alcohols are further characterized by having a minimum of 28 carbon atoms and are preferably unsaturated with a minimum iodine value of 40. The esters are useful as lubricants, release agents, plasticizers, solvents or a modifier additive for such compositions.

Description: HIGH MOLECULAR WEIGHT LIQUID ESTERS BACKGROUND OF THE INVENTION 1. FIELD OF THE INVENTION High molecular weight liquid esters are provided which are useful as lubricants, release agents, plasti- cizers, solvents or a modifier additive for such composi¬ tions. Advantageously they demonstrate characteristics, such as fluidity and high molecular weight combined with lubricating, plasticizing, solvent and mold releasing properties. 2. STATEMENT OF RELATED ART Processes have been developed to produce lubricants by the esterification of alcohols and acids. For example, U.S. Patent No. 2,862,013 relates to the esterification of branched chain liquid alcohols containing from 24 to 28 carbon atoms with acids having from 12 to 18 carbon atoms to produce functional fluids on the low end of the range up to high melting point waxes on the high end of the range. Another reference which discusses the production of lubricants is U.S. Patent No. 4,157,990. This reference indicates that esters of polycarboxylic acids and long chain aliphatic monovalent alcohols can be used to give fluidity to thermoplastic materials. This reference fur- ther describes the esterification of dicarboxylic acids, and monocarboxylic acids having from 12 to 30 carbon atoms with aliphatic polyols to produce lubricant takifiers. This reference also indicates that the esters of long chained fatty acids are used to improve fluidity. It has now been discovered that the esterification of branched, unsaturated alcohols having a minimum of 28 carbon atoms with polymeric fat acids having a minimum of 24 carbon atoms will produce liquid lubricants having an unusually high molecular weight combined with other desired characteristics such as low solidification points, low mobility, vapor pressure and volatility. These pro¬ perties make the liquid, high molecular weight esters of the instant invention useful as lubricants, plasticizers, and mold release agents. The usefulness of these esters, moreover, is enhanced by the high molecular weight of the constituents (the original polymeric fat acids and alcohols). BRIEF DESCRIPTION OF THE INVENTION The composition provided for comprises: A liquid ester of a polymeric fat acid and a branched aliphatic primary alcohol, the alcohol having from about 28 to about 60 carbon atoms. The polymeric fat acids employed in this invention are well known and commercially available. They may be fractionated to provide polymeric fat acids with high di er or trimer content and can be hydrogenated to be substantially saturated, although unsaturation is pre¬ ferred. Those employed herein will generally have from about 24 to about 90 carbon atoms. The branched aliphatic primary alcohols used in this invention are prepared by the condensation (guerbet reac¬ tion) of alcohols containing from 14 to about 30 carbon atoms which will provide the branched aliphatic primary alcohols having the 28-60 carbon atoms. The liquid esters of this invention which will gener- ally contain about 52-150 carbon atoms can also be repre¬ sented by the formula: where R- j is the branched aliphatic hydrocarbon radical or ligand of the primary branched alcohol, and, as such, has a minimum of 2. carbon atoms; R 2 is the hydrocarbon ra¬ dical or ligand of a polymeric fat acid; n is an integer which depends on the number of carboxyl groups present in the polymeric form of the polymeric fat acid and R.-. is hydrogen or the branched aliphatic hydrocarbon radical or ligand of the primary, branched alcohol, and has a minimum of 28 carbon atoms. 3 and R-^ can be from the same or different alcohols. The range of carbon atoms for R« is generally from about 22 to about 88. The esters of the instant invention advantageously are capable of retaining desirable properties in spite of the breakdown typical to esters particularly when exposed to high temperature conditions in their area of use. This breakdown results in significant amounts of the original ester forming acids and alcohols being present either during use or storage. The instant invention prolongs life and usefulness of the esters in spite of these quan¬ tities of acids and alcohols due to the molecular weight, character, and properties of the alcohols and acids used as feeds. T e esters described herein, thus, in spite of typical breakdown, tend to retain such properties as high vapor pressure, good fluidity, low volatility, high smoke points, low flammability, good solvent properties, and goor' lubrication properties. DFTAILED DESCRIPTION OF THE INVENTION As indicated earlier, the compounds of the instant invention are liquid esters of a polymeric fat acid and a branched, aliphatic primary alcohol. The esters will generally have in the range of from about 52 to about 150 carbon atoms and may be represented by the following gen¬ eral structure: 0 0 II II R 1 -0-C-R 2 - (C-O-R3)n In this structure, Rn is the branched aliphatic lig¬ and of the primary branched alcohol, and, as such, has a minimum of 28 carbon atoms; R 2 is the hydrocarbon ligand of a polymeric fat acid; n is an integer dependent on the number of carboxyl groups in the polymeric fat acid and can range from 1 to 5, g can be either a hydrogen, or the branched aliphatic ligand of the primary, branched alco¬ hol, and has a minimum of 28 carbon atoms. g and R, can be from the same or different alcohols. The range of carbon atoms for R 9 is generally from about 22 to about 88. The integer n is preferably 1 or 2 for the respective dimers and trimers which contain 2 and 3 carboxylic groups respectively. When n is 3, 4 or 5, the higher polymeric forms, such as the tetramer, pentamer or hexamer, are included. These are generally found in small amounts, if any, in available polymeric fat acids. The alcohols used for esterification should have at least one branch per molecule. This branch, moreover, should not be off of the hydroxyl carbon, thus, the alco- hols must also be primary, with from about 28 to about 60 carbon atoms. A mixture of branched aliphatic primary alcohols can be used in esterification. Preferably the alcohol feed is unsaturated, the unsaturation level of the feed acceptably, having a minimum iodine value of at about 40; most preferably, the iodine value being in the range of from about 70 to about 120. Alcohols of the type called for by the instant pro¬ cess can be prepared from other alcohols by condensation or "guerbetization". A preferred method to obtain the alcohols required by the instant invention is to use a guerbet type reaction whereby oleyl alcohols are condensed to form branched dioleyl primary alcohols. This type of reaction is well-known in the art, and can be found de¬ scribed in Swiss Patent 231,252 to Henkel and Cie GmbH, and in U.S. Patent Nos. 2,836,628; 3,1_9,880; 3,328,470; 3,558,716; 4,011,273; and 3,479,412. Any of these described methods can be used to condense oleylic alcohols forming primary branched unsaturated alcohols and are suitable to produce the alcohols used in the instant in¬ vention as would be any method capable of condensing an oleylic alcohol without destroying unsaturation. The instant invention, however, is not limited to alcohols produced by these methods, since any primary, branched, alcohols having from 28 to 60 carbon atoms can be used including any that are naturally found. Both branched or linear primary alcohols can be used in condensation or guerbet-type reactions to produce the alcohols needed in the instant invention. The alcohols used in such condensation type reactions must have a mini¬ mum of 14 carbon atoms, an acceptable range being from about 14 to about 30 carbon atoms. These will thus pro¬ vide primary branched alcohols having 28-60 carbon atoms. Preferably, the esterification feed is produced from alcohols having from about 14 to about 24 carbon atoms, and are most preferably derived from natural fats and oils. One such preferred alcohol is oleyl alcohol. " • he acids employed to form the esters of the instant invention are polymeric fat acids, generally having from about 24 to 90 carbon atoms. Preferably, those used are the commercially available acids prepared from C,„ fatty acids and have from about 36 to 54 carbon atoms in their respective dimer and trimer forms. Both saturated and unsaturated acids are used although more preferably the acids are unsaturated. The polymeric fat acids are well known and readily available commercially. One method of preparing such pro¬ ducts is shown in U.S. Patent 3,157,681. This patent also contains a general description of various other -methods such as U.S. Patent 2,347,562; 2,417,738; 2,426,489; 2,450,332; 2,673,184; 2,793,219; 2,793,220 and 2,955,121, which description is hereby incorporated by reference. Briefly the preferred method of preparing polymeric fat acids is by a process of polymerization consisting of heating unsaturated fatty acids (either an individual acid or mixtures thereof) derived from fats or oils at tempera¬ tures in the range of 180-200°C. in the presence of a clay catalyst. The usual temperature employed is 200-250°C. with about 230°C. being preferred. The term "polymeric fat acids" as used herein is intended to be generic to polymerized acids obtained from "fat acids." The term "fat acids" is intended to include saturated, ethylenically unsaturated and acetylenically unsaturated, naturally occurring and synthetic, monobasic aliphatic acids containing from 12 to about 24 carbon atoms, which will provide polymeric fat acids containing from about 24 to about 90 carbon atoms in their predomi- nant dimer and trimer forms. The saturated, ethylenically unsaturated and acety¬ lenically unsaturated fat acids are generally polymerized by somewhat different techniques, but because of the func¬ tional similarity of the polymerization products, they all are generally referred to as "polymeric fat acids. " Saturated fat acids are difficult to polymerize but polymerization can be obtained at elevated temperatures with a peroxidic catalyst such as di-t-butyl peroxide. Because of the generally low yields of polymeric products, these materials are not currently commercially signifi¬ cant. Suitable saturated fat acids include branched and straight chain acids such as caprylic acid, pelargonic acid, capriσ acid,lauric acid, myristic acid, palmitic acid, isopalmitic acid stearic acid, arachidic acid, be- henic acid, and lignoceriσ acid. The ethylenically unsaturated acids are much more readily polymerized. Catalytic or non-catalytic polym¬ erization techniques can be employed. The non-catalytic polymerization generally requires a higher temperature. Suitable catalysts for the polymerization include acid or alkaline clays, di-t-butyl peroxide, boron trifluoride and other Lewis acids, anthraquinone, sulfur dioxide and the like. Suitable monomers include the branched and straight chain, poly- and ono-ethylenically unsaturated acids such as 3-octenoic acid, 11-dodecanoic acid, lineric acid, lauroleic acid, myristoleic acid, tsuzuic acid, palmito- leic acid, gadoleic acid, cetoleic acid, nervonic acid, moroctic acid, timnodonic acid, eicosatetraenoic acid, nisinic acid, scoliodonic acid and chaulmoogric acid. The acetylenically unsaturated fat acids can be poly- erized by simply heating the acids. Polymerization of these highly reactive materials will occur in the absence of a catalyst. The acetylenically unsaturated acids occur only rarely in nature and are expensive to sythesize. Therefore, they are not currently of commerical signifi- cance. Any acetylenically unsaturated fat acid, both straight chain and branched chain, both mono-unsaturated and poly-unsaturated, are useful monomers for the prepara¬ tion of the polymeric fat acids. Suitable examples of such materials include 10-undecynoic acid, tariric acid, stearolic acid, behenolic acid and isa ic acid. Because of their ready availability and relative ease of polymerization, oleic and linoleic acid are the pre¬ ferred starting materials for the preparation of the poly¬ meric fat acids, a mixture of which is found in tall oil fatty acids, which is accordingly the most common commer¬ cial starting material. Having obtained the polymeric fat acids or deriva¬ tives as described above, they may then be fractionated, for example, by conventional techniques of distillation or solvent extraction. Where color and stability of the polymers are particularly important, hydrogenated and fractionated polymeric fat acids are the preferred start¬ ing materials. Typical compositions of commercially available poly- meric fat acids, based on unsaturated C-.g fat acids, which are suitable for the esters of the instant invention are: Cig monobasic acids ("monomer") 5-15% by weight; C 36 dibasic acids ("dimer") 60-80% by weight; C 54 (and higher ("trimer") polybasic acids 10-35% by weight. The relative ratios of monomer, dimer and trimer (or higher) in unfractionated polymeric fat acids are depen¬ dent on the nature of the starting material and the condi¬ tions of polymerization. - For the purposes of this inven¬ tion, the term monomeric fat acids refers to the unpoly- merized monomeric acids; the term dimeric fat acids refers to the dimeric acids or derivatives (formed by the dimeri- zation of two fat acid molecules) ; and the term trimeric fat acids refers to the residual higher polymeric forms consisting primarily of trimeric acids or derivatives, but containing some higher polymeric forms. Reference has been made above to the monomeric dimer¬ ic and trimeric fat acids present in the polymeric fat acids. The amounts of monomeric fat acids, often referred to as monomer (M) , dimeric fat acids, often referred to as dimer (D) , and trimeric or higher polymeric forms, often referred to as trimer (T) , may be determined by gas liquid chromatography (GLC) of the methyl esters of the polymeric fat acids. In this method of analysis, an intermediate (I) is seen between the monomer and dimer forms. It is desirable that this intermediate be low, but polymeric fat acids generally having less than 10%, and preferably less than 6% intermediate by weight are satisfactory. Unless otherwise indicated, this analytical method was employed in the analysis of the polymeric fat acids employed in this invention. Mixtures may be* fractionated by suitable means such as high vacuum distillation or solvent extra-ction tech¬ niques so as to obtain dimer acid cuts of greater than 80%, and above 90% or about 95% dimeric species by weight. These dimer-rich fractions can also be used as the starting materials in an esterification to produce the liquid esters of the instant invention. Mixtures of poly¬ meric fat acids dimeric and trimeric that can also be used to produce these esters. The liquid esters of the instant invention are ob- tained by esterification procedures. Any known esterifi- cation process is acceptable. For example, an esterifica- tion which will produce the esters of the instant inven¬ tion can be done by the combination of the previously described alcohols and polymeric fatty acids at tempera- tures in the range of from about 50° to about 300°C. Generally, the reaction will proceed without cata¬ lysts although there are a variety of esterification cata¬ lysts, and any of these may be used to produce the com¬ pounds of the instant invention. Representative, but non- exhaustive examples of such catalysts are: mineral acids, or bases such as sodium hydroxide and potassium hydroxide, alkali metal alkoxides such as sodium or potassium alkox- ide, aluminum alkoxide, and divalent metal salts such as zinc salts, and manganese acetate, sodium methylate, and metal such as zinc and nickel. Acidic resins have also been used as esterification catalysts. An example of such catalysts which are also acceptable are the sulfonated polystyrene resins. Other substances which have been used to catalyze esterification reactions which may be used to produce the esters of the instant invention are: phenol, formaldehyde, tin oxides and hydrosulfonic acid resins. To produce the esters of the instant invention preferably the temperature is from 75°C. to about 300°C. Pressure is not a critical factor and any pressure convenient for the esterification process used is accept¬ able. It may, however, be preferred to produce the esters herein described by an esterification process conducted under less than atmospheric pressure or under an inert atmosphere. This would decrease oxidation and ensure a clear product which would be acceptable for use as a plas- ticizer. The esterification reaction can be controlled so that the acidity of the product is higher or lower. Thus, for example, it is possible to conduct step-wise esterifica- tions which substantially completes the esterification of the dibasic acids, but which would esterify two of the acid ligands of the high polymeric fat acids For such an esterification the alcohol to polymeric fatty acid mole ratio should be at least 2 to 1, preferably 2.25 to 1. This would produce a less acidic ester product than would a process having only that amount of alcohol necessary to esterify one acid ligand per polymeric fatty acid mole¬ cule. To esterify only one ligand there should be at least a sufficient amount of alcohol to ensure an esteri- fication product of such a highly acidic nature, there- fore, the alcohol to polymeric fatty acid mole ratio should be at least 1 to 1; and more preferably 1.5 to 1. For more complete esterifications, the alcohol concentra¬ tion should be increased. For a complete esterification the ratio of alcohol to acid ligand should be 1:1. An acceptable overall range for the' mole ratio of alcohol to polymeric fatty acid is from about 1 to 1 to about 4 to 1. The following examples are offered to illustrate the instant invention and not to limit it. All parts and per- centages are by weight unless otherwise specified. EXAMPLE I Starting polymeric fat acid materials used to prepare the esters described herein were a predominantly trimeric fat acid (commercial designation VERSA ' TRYME® 213) and a predominantly dimeric fat acid (commercial designation VERSADYME® 52) . The composition of these acids, which are polymerized tall oil acids determined by gas liquid chro- atography (GLC) of the methyl esters of the polymeric fat acids, as earlier noted, are reported as the following typical composition according to the manufacturers speci¬ fication: 213 Product 52 Product % monomer (M) by weight 4% max 2% max % dimer (D) by weight 25-45% 88% min % trimer (T) by weight 50-75% 5% max % intermediate(I) by weight 3% max 6% max The branched unsaturated primary alcohols used were essentially dioleyl guerbet alcohol (alcohol A) and having from about 32 to about 38 carbon atoms per molecule, with less than 10% trioleyl guerbet alcohols. The iodine value of these alcohols was 90 to 95. Primary saturated, branched alcohols were also esterified. Three esterifications were completed, one using saturated branched alcohols having molecular weight ranges of from 24 to 28 carbon atoms (alcohol B) and two with alcohols having from 32 to 36 carbon atoms (alcohol C). in all of the esterifications, the alcohol to acid ligand ratio used was 1:1. Thus, equal equivalents of acid and alcohol were mixed together with 0.25% by weight tin oxide. The following general procedure was used: The reaction mixture was heated at 185°C until the evolution of water was completed, while a nitrogen sparge was applied. To help complete the reaction further, vacuum was applied down to 100 torr and the solution was again heated to 200 β C until water formation again stopped. Thereafter, a vacuum of 5 torr or less was applied and the mixture was heated to the range of about 260° to 280°C but no further water formation was observed. The reaction mixture was then cooled to 95°C and filtered. The liquids were clear but slightly colored. All esters were fluid, and the esters of the trimer acids were substantially less viscous than the acid itself. ESTERS OF DIMER AND TRIMER ACIDS THE ESTER OF PRODUCT PRODUCT POLYMERIC ACID OH SAPON. FLUID ALCOHOL & ACID VALUE VALUE VALUE AT A 213 5.7 0.11 70.0 fluid at -8°C A 52 4.0 4.5 70.1 fluid at -8°C B 213 2.4 5.7 81.8 fluid at 4°C solid at -8°C 213 12.2 0.4 87.3 solid at -8°C 52 17.3 8.4 solid at -8°C

Claims: WHAT IS CLAIMED IS: 1. A liquid ester of a polymeric fat acid and a branched, aliphatic primary alcohol having from about 28 to 60 carbon atoms. 2. An ester as described in claim 1 wherein the polymeric fat acid contains from about 24 to about 90 carbon atoms. 3. An ester as described in claim 2 wherein the alcohol is unsaturated. 4. An ester as described in claim 3 wherein the minimum unsaturation level of the alcohol gives an iodine value of 40. 5. An ester as described in claim 4 wherein the polymeric fat acid used has from about 36 to 54 carbon atoms. 6. An ester as described in claim 5 wherein the iodine value of the alcohol is in the range of from about 70 to about 120. 7. An ester as defined in claim 1 in which said polymeric fat acid is a polymeric fat acid of an unsaturated monocarboxylic fatty acid containing 18 carbon atoms. 8. An ester as defined in claim 7 in which said unsatu¬ rated fatty acid is oleic acid. 9. An ester as defined in claim 7 in which said unsatu¬ rated fatty acid is linoleiσ acid. 10. An ester as defined in claim 7 in which said polymeric fat acid is polymerized tall oil fatty acids. 11. An ester as defined in claim 1 in which said branched aliphatic primary alcohol is an oleyl guerbet alcohol. 12. An ester as defined in claim 11 in which said poly¬ meric fat acid is selected from the groups consisting of the dimeric and trimeric fat acids of tall oil fatty acids and mixtures thereof. 13. A liquid ester having the formula: where R, is the branched aliphatic hydrocarbon radical of a primary branched alcohol having from 28-60 carbon atoms, R is the hydrocarbon radical of a polymeric fat acid, R3 is hydrogen or a branched aliphatic hy¬ drocarbon radical of a primary branched alcohol having from 28-60 carbon atoms and n is an integer of from 1- 5. 14. An ester as defined in claim 13 wherein R is a hydro¬ carbon radical of a polymerized tall oil fatty acid and n is 2. 15. An ester as defined in claim 13 wherein R is a hydro¬ carbon radical of a polymerized tall oil fatty acid and n is 3. 16. An ester as defined in claim 13 wherein R, and R-, are the same and are the hydrocarbon residue of an oleyl guerbet alcohol. 17. A lubricant composition containing the liquid ester of claim 1.

Inventors: LEENDERS PETER, LEENDERS, PETER
Applicants: HENKEL CORP, HENKEL CORPORATION
Application year: 1985
Main classification: C07C67
IPC codes: C07C67, C07C69