DE1021344B - Process for the production of polyhydric alcohols - Google Patents

Description

GERMAN

The invention relates to a process for the preparation of polyhydric alcohols with at most 4 carbon atoms in the molecule by hydroxylating a corresponding unsaturated alcohol in the aqueous Medium in the presence of formic acid, which is then removed from the reaction mixture. The unsaturated alcohol used as the starting material has an olefinic double bond between Carbon atoms that do not have hydroxyl groups. In the multi-valued one to be produced from it Alcohols carry these same carbon atoms but hydroxyl groups, which can be attributed to a reaction is, in the end, to an implementation according to the scheme:

OH OH

-C = C- +

H ₂ O ₂

-C-

-C -

leads.

The production of a polyhydric alcohol from an unsaturated alcohol by means of hydrogen peroxide in the presence of formic acid is already known. Some ways of carrying out this reaction, with 88- to 100 ° / ₀ formic acid, and preferably a highly concentrated (about _90/0 sodium °) hydrogen peroxide to be used are, for example described in Journal of the American Chem. Society, 67 (1945), p 1786 ff., 68 (1946), pp. 1504, 69 (1947), p. 2120, and in Industrial and Engineering Chemistry, 39 (1947), p. 847, and in U.S. Patent 2,492,201. Bei Due to the high concentration of formic acid and hydrogen peroxide, mixtures containing only a small amount of water are obtained in this process after the reaction. Because of this, the concentration of formic acid is high, with the result that the polyhydric alcohol in the final mixture is mainly present in ester form, so that only part of the formic acid can be recovered directly by distillation. The distillation finally gives an azeotropic mixture of water and formic acid which contains about 70 percent by weight of formic acid. The aqueous formic acid cannot be reused as such for the same purpose since the concentration of the formic acid solution to be added must be about 90%.

A further proportion of formic acid can be obtained by cleaving the ester, but is not obtained in a form in which it can be used again immediately. For example, the ester can be subjected to steam treatment or transesterification (ie, a reaction in which the alcohol radical in the ester is replaced by another alcohol radical), as is described, for example, in the United States patent process for preparation
of polyhydric alcohols

Applicant:

NV De Bataafsche Petroleum
Maatschappij, The Hague

Representative: Dr.-Ing. F. Wuesthoff, Dipl.-Ing. G. Pulse

and Dipl.-Chem. Dr. rer. nat. E. Frhr. v. Bad luck man,

Patent Attorneys, Munich 9, Schweigerstr. 2

Claimed priority:
Netherlands May 20, 1954

Jacobus Jan Tjepkema, Amsterdam (Netherlands),
has been named as the inventor

2 500 599, which we will come back to later. However, this means that the Formic acid is obtained either as a very dilute aqueous solution or in a Ester is converted, which is unusable for the process. In addition, there is a certain amount of transesterification additional amount of alcohol required.

Another disadvantage of the method according to US Pat. No. 2,492,201 is that, in order to To achieve economically viable yields, a highly concentrated (preferably 90%) hydrogen peroxide solution needs.

US Pat. No. 2,500,599 describes, among other things, the preparation of glycerol from allyl alcohol and H ₂ O ₂ in dilute aqueous solution in the presence of formic acid. It is true that when a dilute aqueous solution is used, less glycerol formate is formed during the hydroxylation than when working in a concentrated solution, but the formic acid cannot be recovered from the reaction mixture in pure form, since the azeotrope is also here again Water and formic acid, which contains about 70% formic acid and boils at 108 °, forms during the distillation (see also US Pat. No. 2,555,927, column 1, lines 37 ff.). At this stage of the distillation, the glycerine is therefore in contact with the 70% formic acid at 108 °, so that an esterification takes place after all. From the distillation residue, which as a result of a concentrated aqueous glycerine

709 846/472

3 4

solution and a not inconsiderable amount of glycerinization or, at a later stage, also to esterify exists, can now, as already shown, be added after a.

in U.S. Patent 2,500,599. The hydroxylation can be carried out using over

drive, for example by means of steam treatment or the room temperature to preferably 50 to 100 ° Transesterification, pure glycerine can be obtained, whereby 5 elevated temperatures are accelerated, the formic acid in a not immediately recovered The process according to the invention is special

usable form is recovered. applicable for the production of glycerine by

Another process for making glycerine is hydroxylation of allyl alcohol. In this case, allyl formate is obtained from allyl alcohol in an aqueous medium by hydroxylamine during the distillation. This reaction with H ₂ O ₂ consists in the fact that the reaction in io ester can be used as a starting material for a subsequent environment of metal oxides, such as osmium tetraoxide, and for this purpose it is carried out in or tungsten trioxide. Such procedures are returned to the reaction vessel. The transesterification are z. B. in Dutch patent 56506 from glycerol formates to allyl formate and United States and USA patents 2,373,972. Esterification of the free formic acid to allyl formate can. Although glycerol can be accelerated to a good extent by this process, if necessary, by being available, the expensive catalysts could not so far be readily available for a small amount of an inorganic acid, such as catalysts the practice suitable H ₂ SO ₁ or H ₃ PO ₄ , admits.

in a nice way. Is distilled according to the invention at atmospheric

The method according to the invention enables the pressure to be obtained in succession two azeotropes,

Above-mentioned disadvantages, at least for the most part, 20 namely initially a ternary azeotrope, which at about

to avoid. 72 ^ boils and about 80% from allyl formate, to 5%

Is prepared by hydroxylating a corresponding un- of water and to 15 ° / ₀ of allyl alcohol, and

saturated alcohol in aqueous solution in the presence then a binary azeotrope, boiling at about 89 ° of formic acid, a polyhydric alcohol _'o made with and to 72 ° / of allyl alcohol to 28% water, at most 4 carbon atoms, which is 25th

Formic acid at the end from the reaction mixture It is usually advisable to use the

is recovered by reducing the amount of allyl alcohol present in the solution to a non Subjects to distillation at atmospheric pressure or more than four-fold excess over that present under Pressure increase can be carried out; here to limit the allyl formate. This amount is enough care must be taken that the unsaturated alcohol in 30 for distillation according to the invention, and a separate of the solution compared to the formic acid and the addition of allyl alcohol after the hydroxylation Formate of the polyhydric alcohol in excess is then unnecessary.

remains, for what purpose before, during or after are particularly favorable in the reaction mixture H ₂ O ₂ -

the hydroxylation a sufficient amount of unsaturated concentrations of 1 to 20 percent by weight. at Adding alcohol that is not hydroxylated. 35 Application of lower concentrations runs the

The unsaturated alcohol and the formic acid, the reaction too slow, and the resulting glycerine for The hydroxylation can be applied solution is overly dilute. Is the concentration in the be wholly or partially esterified with one another. Reaction mixture higher than 20 percent by weight, see above

In the distillation according to the invention too many by-products are formed, and moreover Formic acid in the form of its ester with the unsaturated 40 is then obtained in concentrated solutions, from which Alcohol together with the excess of the latter make the formic acid more difficult to recover. distilled off so that an aqueous solution of the formed The method according to the invention can also

polyhydric alcohol remains. The process with relatively good success for the production of according to the invention therefore has the advantage that 2- or 1-methylglycerol from methylallyl alcohol or from No formation of the azeotropic 45 crotyl alcohol or methyl vinyl carbinol are used during the distillation. Mixture of 70% formic acid and water enters, so that not a considerable part of the gebil- Example 1 deten polyhydric alcohol to formic acid ester

implements; a mixture of 368 g glycerine, 400 g water, 184 g

Any small amounts of ester present from more than 50 formic acid and 364 g of allyl alcohol were distilled, alcohol and formic acid again until the boiling point of the water was reached. 88 Mols of sought-after polyhydric alcohol split. A percent of the formic acid originally present was another benefit of the process according to the invention, and was recovered in the distillate as allyl formate in that the obtained by adding excess.

unsaturated alcohol formed ester below the 55. The experiment proved in principle that practically the Boiling point of water come to the boil, so that all formic acid, d. H. both those in free form only a relatively small amount of water bound in with the present than that as glycerine formate Esters distilled over and you can conveniently form of allyl formate from the reaction mixture aqueous solutions of the desired polyhydric alcohol can be recovered in the first stage, receives. 60

The formic acid esters obtained by distillation, Example 2

as such, according to the invention, can be used as the starting product

be used in a new hydroxylation, since 2 moles of allyl formate together with 1 mole of H ₂ O ₂ (to-

contrary to the expectation it was found that given in an aqueous solution as a 30% solution) a partial splitting of the ester rapidly occurs for 4 hours with solution in a round unsaturated alcohol and formic acid with stirring in a reflux condenser, which keeps the flask at boiling temperature (bottom temperature leads to that the hydroxylation of the free temperature 79 °). Already after 15 minutes the original formic acid is accelerated, can take place. The lent heterogeneous system homogeneous, and after 4 hours unsaturated alcohols distilled off can of course all the hydrogen peroxide was consumed. The reaction mixture either at the beginning of the hydroxy 70 was then 1.33 mol of allyl alcohol and 2.5 cm ³

Claims (2)

5 6 36% HCl was added, after which it was carried out by distillation, so that it was only necessary to add a small amount of formic acid initially formed and the unconverted amount in order to be able to continue the hydroxylation of allyl formate in the form of a ternary azeotrope . Men with allyl alcohol and water (bp about 72 °) over- The remaining aqueous solution contained about 10%, while later a binary allyl 5 glycerine; the following alcohol-water azeotrope (boiling point approx. 89 °) was transferred from it by distillation. The products obtained: The residue consisted of an approximately 50% strength aqueous allyl glycerol ether, less than 5 mol percent glycerol solution from which 75 to 80 mol percent of the glycerol was obtained by neutralization after neutralization with NaOH. polyglycerin (residue) 10 to 15 mol percent The yield of distilled glycerol, calculated on the allyl groups, was 62.5 mol percent, calculated on The percentage figures for the yield relate to H2O2 42.5 mol percent. During this distillation, the amount of allyl alcohol that was not recovered fell. Residue, which probably consisted of polyglycerins. Claims: Example 3 1 ^ 1. Process for the production of polyvalent In the same manner as in Example 2, there were 2 moles of alcohols having not more than 4 carbon atoms Allyl formate heated, this time with 2.2 mol of H ₂ O ₂ in shape in the molecule by hydroxylation of a corresponding a 30% solution. The bottom temperature fluctuated in the unsaturated alcohol in the aqueous medium in this case between about 50 to 60 °. After the presence of formic acid, which is Reaction time of about 10 hours was the drawing that the reaction mixture for removal added H ₂ O ₂ reacted, some of which turned into water of formic acid in the presence of a distillation and decomposed oxygen. an excess of unsaturated alcohol against The amount above the formic acid and the formic acid ester added after the reaction has ended of allyl alcohol was 3 moles; the mixture was subjected to the same as the polyhydric alcohol being subjected to worked up in Example 2. The yield was the formic acid as an ester of the unsaturated alcohol 60 mole percent calculated on allyl formate. distilled off. 2. The method according to claim 1, characterized in-Example 4 is characterized in that the distilled mixture of ants 30 acid esters and excess unsaturated alcohol A mixture of 2 moles of allyl formate, 2 moles of allyl as a starting product for the production of more- alcohol, 2 moles of hydrogen peroxide and 1400 cm ^{3 of} water of hydric alcohol are reused, was kept in reaction for 14 hours at 80 °, according to which 3. The method according to claim 1 and 2, characterized the hydrogen peroxide consumed to 99 mole percent characterized that the distillation at increased was. The reaction mixture was carried out after adding 35 pressure. 2 moles of allyl alcohol using a suitable 4. The method according to claim 1 to 3, characterized Distillation column distilled. characterized in that the hydroxylation at a The product boiling below 100 ° contained 4.05 mol, temperature between 50 and 100 ° is carried out, olefinic compounds (allyl formate and allyl alcohol) 5. The method according to claim 1 to 4, characterized and 1.82 mol of formic acid in free and esterified 40, which is methyl- State. This product can be re-circulated using alcohol or crotyl alcohol. © 709 8Φ6 / 472 12. 57