Classifications

• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C51/00—Preparation of carboxylic acids or their salts, halides or anhydrides
  • C07C51/347—Preparation of carboxylic acids or their salts, halides or anhydrides by reactions not involving formation of carboxyl groups
  • C07C51/36—Preparation of carboxylic acids or their salts, halides or anhydrides by reactions not involving formation of carboxyl groups by hydrogenation of carbon-to-carbon unsaturated bonds
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C51/00—Preparation of carboxylic acids or their salts, halides or anhydrides
  • C07C51/42—Separation; Purification; Stabilisation; Use of additives
  • C07C51/487—Separation; Purification; Stabilisation; Use of additives by treatment giving rise to chemical modification
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F8/00—Chemical modification by after-treatment
  • C08F8/04—Reduction, e.g. hydrogenation
• • C—CHEMISTRY; METALLURGY
  • C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
  • C11C—FATTY ACIDS FROM FATS, OILS OR WAXES; CANDLES; FATS, OILS OR FATTY ACIDS BY CHEMICAL MODIFICATION OF FATS, OILS, OR FATTY ACIDS OBTAINED THEREFROM
  • C11C3/00—Fats, oils, or fatty acids by chemical modification of fats, oils, or fatty acids obtained therefrom
  • C11C3/12—Fats, oils, or fatty acids by chemical modification of fats, oils, or fatty acids obtained therefrom by hydrogenation
  • C11C3/126—Fats, oils, or fatty acids by chemical modification of fats, oils, or fatty acids obtained therefrom by hydrogenation using catalysts based principally on other metals or derivates

Definitions

• the present invention relates to a process for the preparation of a trimer acids product of improved colour.
• Trimer acid products comprising 80 wt% or more of trimer acids and higher polycarboxylic acids usually are obtained as a by-product of the dimerization of C 14 to C 2 unsaturated fatty acids and mixtures thereof, in particular such mixtures containing C 18 unsaturated fatty acids.
• the starting product for the dimerization process usually is a mixture of tall oil fatty acids, although other unsaturated fatty acids feedstocks may be used as starting products.
• the main product of the dimerization process are dimer acids.However the product of the dimerization process usually does not contain more than about 85 % by weight of such dimer acids, the remaining part consisting of trimer acids, higher polycarboxylic acids and some monomer acids (unchanged, cyclized, aromatized and isomerized monocarboxylic fatty acids) .
• the relative amount of dimer acids in the dimerization product can be increased by distilling off
• a direct hydrogenation of trimer acids therefore is hardly possible, it requires a high amount of catalyst at a rather high temperature. he catalyst can only be separated from the hydrogenated product with difficulty. It is an object of the present invention to provide a process for the preparation of a trimer acids product of improved colour, the colour being lighter than the colour of a starting product high in trimer acids such as the residue obtained by a dimerizing process as described in the preceding paragraph, thereby broadening the spectrum of possible applications of the trimer acids product and precluding the disposal of an objectionable product harmful to the environment. It is a further object of the invention to provide a process allowing hydrogenation at a reasonable temperature and easy removal of the catalyst after hydrogenation.
• trimer acid product In "Fatty Acids in Industry", editor R.W.Johnson and E. Fritz (Marcel Dekker Inc; New York, 1989) page 161, last four lines, it has been suggested that a light-coloured, low- iodine value trimer acid product could be produced by the hydrogenation of a commercial dimer acid made from oleic acid, followed by separation of the dimer-trimer acid in a molecular still.No further details as to the process and about colour and viscosity of the resulting trimer acid product have been disclosed in table 7, page 167, referred to on page 161, last four lines.According to table 7, the trimer acid product only contains 60 % of trimer acids, rest dimer acids.A process as suggested cannot be used in case it is intended to produce non-hydrogenated dimer acids.
• the invention now provides a process for the preparation of trimer acids of improved colour.
• a highly viscous trimer acids starting product of dark colour such as obtained by dimerizing unsaturated fatty acids and distilling off monocarboxylic fatty acids and dimer acids according to a process known in the art, is mixed with an amount of monocarboxylic acid, which is sufficient to obtain a mixture of trimer acids and monocarboxylic acids, having a viscosity low enough to allow in a following step of the process hydrogenation of the resulting mixture of trimer acids and monocarboxylic acids in the presence of a hydrogenation catalyst and ready removal of the catalyst after hydrogenation, after which the hydrogenated mixture is separated by distillation in a first fraction containing predominantly monocarboxylic acid and a second fraction comprising trimer acids of a colour which is substantially lighter than the colour of the original trimer acids starting product.
• trimerizing fatty acids resulting in a mixture of dimer acids, monocarboxylic fatty acids and trimer acids may be used to obtain the trimer acids starting product of the invented process for obtaining a light-coloured trimer acids product.
• Dimerization may for instance be carried out in the presence of 4 to 10 wt% of a natural clay catalyst such as ontmorillonite clay at a temperature of 230 to 265 °C for 2 to 7 hours under a steam pressure of 2 to 10 bar.
• a natural clay catalyst such as ontmorillonite clay
• the clay catalyst is usually removed by filtration, and the monocarboxylic fatty acid is removed by conventional vacuum distillation.
• a product containing a high amount of dimer acids may be obtained by wiped-film evaporation or molecular distillation.A process which is commercially utilized is for example described in Kirk-Othmer, Encyclopedia of Chemical Technology third.ed. , vol.7 page
• the colour of the hydrogenated trimer acids product obtained with the process according to the present invention is a transparent dark yellow, lighter than Gardner colour (1963) 9, typically lighter than Gardner colour (1963) 8.
• the product may be used in the preparation of polymers such as polyesters and polyamide ⁇ , to be used in inks, coatings etc., in a pure form or mixed with dimer acids and monomer products.
• the trimer acids starting product of dark colour is mixed with a saturated monocarboxylic fatty acid or a mixture of such acids having 14 to 24 carbon atoms in their molecule.Heat may be applied to facilitate mixing, in particular in case monocarboxylic fatty acids which are solid at ambient temperature are used.
• Preferred saturated monocarboxylic fatty acids are palmitic acid and stearic acid and mixtures comprising such acids.It is however also possible to use the monocarboxylic acids mixture obtained in the distillation of the crude product of the dimerization of unsaturated fatty acids as a first fraction or fore-cut.
• a mixture of low enough viscosity to allow hydrogenation in the presence of an effective amount of catalyst and ready removal of the catalyst from the mixture after completion of the hydrogenation is obtained by mixing three parts by weight of the trimer acids starting product with one part by weight of monocarboxylic fatty acid.However smaller or greater relative amounts of monocarboxylic acid may be used, if desirable, to obtain
• the hydrogenation of the trimer acids - monocarboxylic acid mixture may be carried out in the presence of a metal catalyst such as nickel, copper, cobalt, platinum, palladium, rhodium and mixtures of these metals and other hydrogenation catalysts known in the art.
• the metal catalyst may be present on an inert carrier material such as kieselguhr, silica, alumina, aluminosilicates or carbon.It is not necessary to use a fresh catalyst in the process according to the invention.
• a catalyst which has previously been used for instance in the hydrogenation of unsaturated fatty acids after its recovery may be used as a catalyst in the process according to the invention.
• Ad viscosities of the mixture lower than for instance 250 mPa.s at 80 °C amounts of catalyst up to 0.050 wt% metal relative to the amount of the mixture can be used.
• Hydrogenation of the trimer acids - monocarboxylic acid mixture may be carried out in a known manner, for example in a dead-end autoclave into which hydrogen is led, while heating and agitating the contents of the autoclave.
• the present invention also relates to the use of the light coloured trimer acid product in the manufacture of polymers which are selected from the group consisting of polyesters (including alkyd resins) , polyamides, polyesteramides, polyurethanes, polyepoxides, and mixtures thereof.
• a trimer acids starting product comprising 90 wt% of trimer acids, about 10 wt% of dimer acids and at least 0.5 wt% of monocarboxylic acids, which was obtained by dimerizing in a conventional way a mixture of fatty acids predominantly consisting of unsaturated C 18 fatty acids and distilling off the greater part of the dimerized fatty acids was subjected to the method according to the invention.
• the viscosity of the product at 80 °C was 1400 mPa.s and the trimer acids starting product had a Gardner colour (1963) of between 13 and

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• Organic Chemistry (AREA)
• Chemical Kinetics & Catalysis (AREA)
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• Life Sciences & Earth Sciences (AREA)
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• Medicinal Chemistry (AREA)
• Polymers & Plastics (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
• Production Of Liquid Hydrocarbon Mixture For Refining Petroleum (AREA)
• Polyamides (AREA)
• Epoxy Resins (AREA)

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Citations (2)

• 1993
  • 1993-11-15 WO PCT/EP1993/003190 patent/WO1994012459A1/en not_active Ceased
  • 1993-11-15 EP EP94900146A patent/EP0669908A1/en not_active Withdrawn
  • 1993-11-15 CA CA002149436A patent/CA2149436A1/en not_active Abandoned
  • 1993-11-15 AU AU54658/94A patent/AU5465894A/en not_active Abandoned
  • 1993-11-15 JP JP6507578A patent/JPH08503453A/ja active Pending
  • 1993-11-18 TW TW082109680A patent/TW257769B/zh active
  • 1993-11-19 MY MYPI93002431A patent/MY109342A/en unknown

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