DE892589C - Process for the production of polyhydric alcohols - Google Patents

Description

Process for the preparation of polyhydric alcohols It is known Manufacture of unsuitable alcohols by attaching to compounds with olefinic Double bond in, G # ß, -en- # vart of osmium tetroxide attaches hydrogen peroxide. The high price of osmium and its not easy processing and recovery from the reaction mixture, however, it is possible to carry out this on an industrial scale towards a smooth process.

Mianhati has already tried the usual ones instead of osmium tetroxide oxygen-carrying catalysts, such as iron (II), manganese, chromium and vanadium compounds to use, I do. these show little or no effectiveness. You lead rather, to a considerable decomposition of the hydrogen peroxide, which in some Cases, especially at elevated temperatures, take an extremely stormy course. This and the formation of undesirable, mainly acidic by-products wied, the processing of the resulting products is difficult and the yield greatly diminished.

It has now been found that one can in a simple manner under avoidance of the disadvantages mentioned, polyvalent allcdhole is obtained when looking at connections with an olefinic double bond - tin, in aqueous miedium and in the presence of tungsten or Molybdenum compounds can act as catalysts hydrogen peroxide. A special The advantage of these compounds is that they are practical even at elevated temperatures no or only very little decomposition of the hydrogen peroxide cause. It is thus possible to reduce the reaction rate considerably by increasing the temperature without fear of sudden decomposition of the water peroxy (ds must become. Another advantage is that, even at higher temperatures, only slight Amounts of acidic by-products are formed, whereby the processing of the conversion products is made much easier.

The tungsten and molybdenum bonds are e.g. B ,. Wolfrain acid, Molybdenum, outer, Ph, osphorwo # lfra, msäur, e, Phosphormrolybdi # näure, borotungstic acid or the corresponding. S, alze, such as Natriu-mwungstat, Ammoniummol # bd ## at, Natrilimph. # O, sp.h.o, rwo, I.framat, optionally also mixtures of different ider mentioned compounds. In general It is enough to add 1 to 2,% 'of the catalyst and less. One can add it in dissolved or dispersed form.

The reaction itself is generally carried out in such a way that hydrogen peroxide and the unsaturated compound are added together in approximately molecular amounts. One can, however, also proceed in such a way that one component, e.g. The unsaturated compound, and gradually adding the hydrogen peroxide, it may be advantageous to let the temperature rise towards the end of the reaction. But one can also use the unsaturated compound in more or less large amounts. Use excess or work with additional dilution with water. In general, one works at temperatures between 30 and 100 '.

The heat that is released during the exothermic process can be removed by external cooling or in such a way that, for. B. works at the boiling point, the reaction heats being removed by evaporation of part of the liquid. The use of reduced pressure or the addition of an inert solvent can sometimes be expedient here. If the work continues, it is advantageous to work with devices that allow the desired reaction temperature to be maintained easily by means of good worms, such as snakes or bundles of tubes through which the mixture of reaction participants is allowed to flow. The hydrogen peroxide can be added all at once or at different points to the extent that the reaction is taking place and, if necessary, the temperature at the end of the reaction path can be increased Arranged catalysts, e.g. tungstic acid pressed into pieces, trickle in. To maintain a desired hydrogen ion concentration, acidic, neutral or alkaline buffer substances can also be added; in addition, the hydrogen peroxide can be stabilized with acidic acids in the usual way.

In the British patent publication 5108 # 526 it is already mentioned that molybdenum can also be used as a catalyst for the reaction of olefinic compounds with hydrogen peroxide. There it is prescribed, however, that hydrogen peroxide be used in the form of a solution in a non-aqueous solvent. In contrast, the vorlieg constricting method has the advantage that aqueous solutions of hydrogen peroxide are easier to handle and more convenient -available, wherein at the same time better yields werfden achieved koholen polyvalent Al.

The parts used in the following examples are weight parts. To..2o5 parts of a 70, 30 / 0i # 9, en aqueous solution of allyl alcohol, after the addition of 6 parts of a 2.0% aqueous solution of phosphotungstic acid, 6;?, 4 parts io, Run 9% hydrogen peroxide and then heat the mixture under reflux to the boil. After the onset of the reaction at about 80 ° C, the heating is removed and only heated again towards the end of the reaction. The total reaction time is about 1 hour. In the processing of the reaction mixture, 140 parts of glycerol are obtained, which, taking into account the recovered allyl alcohol, corresponds to a yield of 84%, according to theory.

Example 2 9 parts of a 2% strength aqueous solution of sodium mincer ramat are added to 246 parts of a 70.70 / 01g aqueous solution of allyl alcohol. the solution gradually added 336 parts of 30.30 / 0i (total hydrogen peroxide? -, n. After: 24 hours, the reaction is complete. When working up the reaction mixture, glycerin is obtained in a yield of 7811/0, calculated on converted allyl alcohol.

BeisPlel 3 To 82 parts of a 7'0.7% aqueous solution of allyl alcohol. 2.9 parts of Phosphormoly-bdün, acidic and II: 2 parts of 30.3% hydrogen peroxide are added and the mixture is allowed to react at 40 '. After the hydrogen peroxide has been consumed, which is indicated by the color of the mixture changing from yellow to blue, the product is worked up by distillation, with about 700/0 of the converted allyl alcohol being obtained as glycerine.

EXAMPLE 4 After adding 1 g of Wolfrain Acid S215 parts 6.50 / g of hydrogen peroxide, 7-2 parts of 2-methylallyl alcohol (isobutenol) are allowed to flow and the mixture is then heated to boiling under reflux. When the reaction starts, the catalyst goes into solution. Here: uf 'you remove the heating and only heat it up again towards the end of the implementation. The total reaction time is about 1/2 hours. When the reaction mixture is worked up, 60 g of 2-methylglycerol are obtained, which, taking into account the recovered: 2-meth, yl, a, llyl, alcohol, corresponds to a yield of 73% according to theory.

EXAMPLE 5 To 408 parts of a 710/9% aqueous solution of allyl alcohol are added 85.0 parts of a 100 / vi "aqueous solution of hydrogen peroxide, 1560 parts of water and 5 parts of a 35.50 / ml aqueous solution Solution of crystallized sodium tungstate and then, while swirling around, 10.8 parts of Nornial-S, sulphurized, Ä, ure. The mixture is left to stand at ordinary temperature, whereupon it reacts under a slight increase in temperature over the course of 1 to 2 days Working up this mixture: 218 parts of glycerol are obtained, which, taking into account the recovered allyl alcohol, corresponds to a yield of 95 %, according to theory.

Claims (1)

PATENT CLAIM process for the production of polyhydric alcohols by addition of hydrogen peroxyfd to compounds with olefinic double bonds in the presence of. Ka # talys.ztoren, # characterized in that one works as catalysts in an aqueous medium in the presence of Wolf ram- o & r Mo-1-ybdenverbindungen. Referred to: British Patent Publication No. 508526.