Organic compounds -- part of the class 532-570 series – Organic compounds – Oxygen containing
Patent
1993-03-24
1994-06-28
Evans, Joseph E.
Organic compounds -- part of the class 532-570 series
Organic compounds
Oxygen containing
560263, C07C 4109, C07C 4310
Patent
active
053248635
DESCRIPTION:
BRIEF SUMMARY
The present invention relates to a process for the production of di-trimethylolpropane (di-TMP).
Usually trimethylolpropane (TMP) is produced by a reaction between n-butyraldehyde and formaldehyde in an alkaline aqueous solution, for instance containing sodium hydroxide or calcium hydroxide. At the reaction also oligomers of TMP such as di-TMP, tri-TMP and higher oligomers are formed. Depending on the reaction conditions these oligomers are formed in a higher or lower degree.
For certain purposes it is desirable to produce a pure di-TMP. Di-TMP has for instance a considerable use as a component in binders for paint and resins, photo curing resins, PVC stabilizers etc.
Pure di-TMP can be produced by isolation from the reaction mixture obtained by the normal TMP production. However, this process has several disadvantages. For instance, the process for production and purification of the di-TMP will be complicated. The energy consumption will also be high. In addition the content of di-TMP obtained will be rather moderate even if the TMP process is set to give a maximal yield of di-TMP. Thus, usual TMP-processes cannot meet an increasing demand of di-TMP.
In the U.S. Pat. No. 3,673,226 a process for the production of a synthetic lubricant is shown. Then di-TMP is produced in a first etherification reaction from TMP in a process using an acid catalyst. The reaction is carried out discontinuously at atmospheric pressure during removal of water by means of distillation in the presence of toluene. The known discontinuous process gives low yields since the di-TMP formed is partially further etherified to tri-TMP and other higher oligomers. A number of side reactions also take place.
According to the U.S. patent the di-TMP obtained is totally esterified in a second step. The fully esterified product is then used as a partial component of a synthetic lubricant.
Thus, the usual TMP-process as well as the process according to the U.S. Pat. No. 3,673,226 have drawbacks concerning the production of di-TMP.
According to the present invention it has quite surprisingly been possible to avoid the above disadvantages and bring about a process for the production of di-trimethylolpropane (di-TMP).
The process comprises subjecting a solution containing less than 3 per cent by weight, preferably less than 1 per cent by weight of water, free trimethylolpropane (TMP) and/or a partial ester between TMP and a monocarboxylic acid or its anhydride having 1-4 carbon atoms in the chain, which partial ester on average contains 1.0-2.5, preferably 1.0-2.0 ester groups per molecule, to an etherification reaction by heating to 50.degree.-200.degree. C., preferably 70.degree.-190.degree. C. in the presence of an acid catalyst in a solid state or in a dissolved state until at most 30%, preferably at most 15% of the total content of free TMP and partial ester of TMP in the solution has been etherified to free di-TMP and partial ester of di-TMP respectively, at the same time continuously removing etherification water formed at the etherification reaction at vacuum at a pressure of 0.1-200 mm Hg, preferably 0.1-50 mm Hg or by an azeotropic distillation by means of a compound such as hexane, toluene, xylene or the like forming an azeotropic mixture, and recovering free di-TMP and di-TMP bonded as a partial ester respectively from the reaction mixture in a suitable way.
The acid catalyst used can for instance consist of alkanesulphonic acids such as methane sulphonic acid, aromatic sulphonic acids such as xylene sulphonic acid and p-toluene sulphonic acid as well as sulphuric acid and phosphoric acid and other inorganic and organic acids with a pKs value <4. Also Lewis acids may be used as catalysts. However, according to the invention a catalyst in solid state is often preferred. In this case the catalyst may be present for example as granules, grains, tablets or powder.
As a solid acid catalyst an aromatic polymer containing sulphonic acid groups can be used. One example of such a suitable polymer is a cation exchanging resin in acid form cons
REFERENCES:
patent: 3670013 (1972-06-01), Leibfried
patent: 3673226 (1972-06-01), Malec
patent: 3681440 (1972-08-01), Gash
patent: 3829507 (1974-08-01), Zey
patent: 3968169 (1976-07-01), Seiden et al.
patent: 5254749 (1993-10-01), Kambara et al.
Wagner et al, "Synthetic Organic Chemistry", pp. 169 and 486.
Axelsson Goran
Sjogreen Carl-Axel
Evans Joseph E.
Perstorp AB
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