DE1077649B - Process for the production of polyhydric alcohols from hemicellulose and cellulose-containing vegetable substances - Google Patents

Description

It is known to first produce the easily hydrolyzable hemicelluloses from wood by means of pressure boiling Dissolve with 1% hydrochloric acid (pre-hydrolysis). The pretreated wood is then dried and then treated with 41% hydrochloric acid in countercurrent (main hydrolysis). The next Step is the separation of the lignin and the recovery of the hydrochloric acid. When pre-hydrolysis is a temperature of 180 ° C is required. The pre-hydrolyzate is a brown sludge that looks like this contains a lot of decomposition products that catalytic hydrogenation to obtainable polyvalent ones Alcohols is practically impossible.

It is also no longer new, made from plant substances with a high content of pentosan with about 25 to 38 per cent Hydrochloric acid at ordinary temperature to bring the pentosans into solution and remove the residues after removing the solution of the pentosans with about 40% hydrochloric acid, dissolve the hexoses. Included the cellulose-containing material is used in a sawdust-like fine distribution. It is further known for the selective separation of sugar solutions from easily hydrolyzable and difficult to hydrolyze Carbohydrate components of plant substances, which are produced by a two-stage hydrolysis of the latter using hydrochloric acid have been obtained with the use of organic solvents, the prehydrolysis of Plant substances at ordinary temperature with medium strength hydrochloric acid in the presence of a water and hydrochloric acid-dissolving organic solvent - which has the property of sugar selectively extract - and the main hydrolysis without solvent with highly concentrated hydrochloric acid at ordinary Carry out temperature, whereby an optimal separation according to quantity and percentage composition the sugar components is guaranteed.

Mixtures of mono- and / or disaccharides which caramelize at high temperatures have also been found with polysaccharides, especially dextrin-containing glucose, subject to hydrogenation Temperatures which are increased gradually or continuously during the hydrogenation. Here Pressures of about 100 atmospheres and temperatures of about 140 to 200 ° C are used.

In the method according to the invention - apart from the fact that a different material is used becomes ■ - · in the first stage at about 70 ° C and 60 atmospheres and in the second stage at hydrogenated about 110 ° C and about 40 atmospheres.

Accordingly, the subject matter of the invention is a process for the preparation of polyhydric alcohols from hemicellulose and cellulose-containing vegetable substances by hydrolysis of the same with hydrochloric acid Method of manufacture

of polyhydric alcohols

from hemicellulose and cellulose-containing

vegetable matter

Applicant:
Udic SA, Zug (Switzerland)

Representative: Dipl.-Chem. Dr. A. Ullrich

and Dipl.-Chem. Dr. T. Ullrich, patent attorneys,

Heidelberg, Bismarckstrasse 17th

Claimed priority:
Switzerland from March 11, 1957

Dipl.-Chem. Dr. Alfons Apel, Mannheim-Rheinau,
has been named as the inventor

in several stages, which is characterized in that it is in a finely divided sawdust-like state present starting materials first a pre-hydrolysis with medium strength hydrochloric acid at about Room temperature and then without interruption of a main hydrolysis at the same temperature with subject to highly concentrated hydrochloric acid and the easily decomposable components of the sugar solution of the first Stage under mild conditions, such as low temperature and high hydrogen performance, and the Resistant components of the second stage at a higher temperature with a high reaction rate hydrogenated in a manner known per se. Advantageously, each stage has its own Equipped with hydrogen circulation and its own contact circuit.

The easily decomposable components of a sugar solution in the first stage at a temperature preferably not above 70 ° C and a hydrogen pressure preferably not below 60 atmospheres and the resistant components of the anhydrous solution in the second stage at temperatures preferably not above 110 ⁰ C and a useful Hydrogen pressure preferably not catalytically hydrogenated above 40 atmospheres.

After the pre- and main hydrolysis, the vacuum evaporation, the optional post-hydrolysis, the Discoloration, deacidification and desalination are the relatively inferior pentoses and

909 760/415

Claims (1)

3 4 Hexose mixtures partially or completely to a multi-stirred autoclave, specifically catalytically hydrogenated at a constant temperature of alcohol mixtures. The temperature of 110 ° C and a constant hydrogen pressure hydrogenation is expedient at a relative pressure of 40 atmospheres, also with its own moderately low temperature, ζ. B. between about 70 .Wasserstoffumlauf and its own contact circuit, and 120 ⁰ C, and a, pressure of about. 60, Atmo-; 5 After the contact has been removed, the spherical solution is carried out in order to remove undesired secondary reactions of the polyalcohols. There are 315 getions to avoid. The easily decomposable and important parts of a water-white pure alcohol mixture, slightly resinous sugar components are put into a first implementation stage under gentle hy patent claims
drier conditions such as low temperature and high io Hydrogen presentation, the more resistant future 1. Process for the production of multi-valued Notch constituents in a second stage for higher alcohols from hemicellulose and cellulose-containing alcohols Temperature with high reactivity around, with vegetable matter due to hydrolysis of the same expediently each of the two reaction stages in addition to hydrochloric acid in several stages, thereby its own hydrogen cycle marked with its own 15, that the in finely divided sawing Contact circuit is equipped. . raw materials present in a flour-like state This results in a substantial shortening initially of a pre-hydrolysis with a medium strength the hydrogenation time by more than 50% and other- hydrochloric acid at about room temperature and on on the one hand, a large saving in energy and reaction - without interrupting a main hydrolysis in the- space. 20 same temperature with highly concentrated salt Subject to acid and the easily decomposable . components of the sugar solution of the first stage 1000 parts by weight of a pre-sugar solution from gentle conditions, such as low temperatures Softwood sawdust with 12% total sugar content and high hydrogen content, and the 25 resistant components of the second stage are used to break down the polymers at 130 ° C re-hydrogenated with 0.3 percent by weight of H Cl, then at a higher temperature with high reaction ßend is deionized via ion exchangers and hy- evaporated. The sugar settles in the drying rack. substance as follows: 2. The method according to claim 1, characterized in that 30 shows that each stage has its own water Polymer sugar 4.6% circulation and its own contact circuit ^ f ^ktose , H ⁰ J ₁ ^{0 is} fitted. ! ™ ^ose fi'ij, ' ³ · Method according to claims 1 and 2, thereby Mannose a no / that the easily decomposable Arabmose 4, U / o ₃₅ components of a sugar solution in the first stage ^ ■ ^ylose 24.0 / 0 k _{ei an} x _em p _era t _ur preferably not over 100.0% 7O ⁰ C and a hydrogen pressure preferably not below 60 atmospheres and the resistance 320 parts by weight of this 40% solution are capable components of the anhydrous solution in hourly in continuous operation in 2 stages 40 of the second stage at temperatures preferably catalytically hydrogenated. In this case, the solution initially flows, not above 110 ^° C. and a hydrogen pressure the 10 parts by weight of a Raney catalyst in preferably not more than 40 atmospheres cat- finely divided state contains, with constant lytisch hydrated. Speed at 70 ° C constant internal temperature temperature and 60 atmospheres of constant hydrogen 45 Documents considered:
pressure through a stirred autoclave with hydrogen and German patent specification No. 555 461;
Contact circulation. Then the hydrogenation liquid - German Auslegeschriften No. 1 027 150, 1 034560; speed with the contact suspended therein with the same German patent application N 1498 IVb / 12 ο (remaining speed through a second made known on March 19, 1953). ι © 90Ϊ760 / Φ15 3. € 0 '