DE1069135B - Process for the production of polyhydric alcohols by hydrogenation of sugars with precious metal catalysts - Google Patents

Description

Hang in the production of polyhydric alcohols by catalytic hydrogenation of saccharides Degree of conversion and yield of the desired end product generally depend on critical reaction conditions and in particular on the particular one used Catalyst off. The industrial hydrogenation of saccharides is more economical Polyhydric alcohols are an important factor and generally depends on the particular person being treated Saccharide, the amount of catalyst required to achieve optimal conversion and the optimal temperatures and pressures of the process.

Platinum and palladium can be used as catalyst metals for the hydrogenation of saccharides will. These catalysts now require less catalyst metal than a nickel catalyst, in order to achieve an equivalent hydrogenation under appropriate reaction conditions, but neither Nickel, platinum, or palladium catalysts give rise to reaction temperatures below 160 ° C and pressures below 105 at high degrees of conversion.

According to the method according to the invention, the hydrogenation of monosaccharides and polysaccharides takes place to polyhydric alcohols on a catalyst which even at hydrogenation pressures below 105 at and temperatures below 160 ° C has exceptional effectiveness. Also allows the inventive method the effective hydrogenation of certain sugars, such as grape sugar, at temperatures below the caramel formation temperature, d. H. below 145 ° C. The inventive Procedure can be carried out intermittently as well as continuously.

A ruthenium-containing catalyst is used as the catalyst in the process according to the invention. He can z. B. elemental ruthenium or oxides of the same, such as sesquioxide, and dioxide Tetroxide or ruthenium salts such as barium perruthenite, sodium perruthenite and the like, ruthenates such as the magnesium, strontium, calcium, silver, barium, potassium and sodium ruthenates, perruthenates, such as sodium and potassium perruthenates and the like, ruthenium halides such as ruthenium dichloride, Ruthenium trichloride, ruthenium tetrachloride, ruthenium pentafluoride and the like, ruthenium sulfides such as Ruthenium disulfide, and chlorine salts of ruthenium, such as potassium chloroperruthenate. From these catalysts the elemental ruthenium and the ruthenium oxides due to the unusual catalytic Effectiveness that they have in the method according to the invention, preferred.

In general, the process can be carried out at pressures in the process of manufacture
polyhydric alcohols by hydrogenation of sugars with noble metal catalysts

Applicant:

Engelhard Industries, Inc.,
Newark, NJ (V. St. A.)

Representative: Dr.-Ing. W. Abitz, patent attorney,
Munich 27, Gaußstr. 6th

Claimed priority:
V. St. v. America October 5, 1956

Gertrude Gilman Boyers, Flushing, NY (V. St. Α.),
has been named as the inventor

Range from about 7 to 105 atmospheres can be carried out; higher pressures are useful but do not yield any another advantage. The reaction temperature can range from about 50 to 400, preferably about 80 up to 200 ° C. Temperatures above 200 ° C are suitable for the continuous implementation of the process with those saccharides which, in proportion, do not have such a great tendency to form caramel.

The catalyst metal is generally used in conjunction with an inert catalyst support such as Carbon. Alumina, silica, kieselguhr, synthetic gel, diatomaceous earth and the like used. In addition to the catalysts described above, other suitable catalysts can be used which are a combination of elemental ruthenium and / or ruthenium oxide with a lesser amount of another platinum metal or oxide of the same, such as platinum or palladium or the Oxides thereof. These ruthenium-containing catalysts in which the elemental ruthenium or the ruthenium oxide is present in a mixture with another metal of the platinum group or oxide of the same, contain the ruthenium in an amount of

90 »649/416

(IUA, ί

1 069 1 3 p

about 5 to 95, preferably at least 50 percent by weight of the content of the catalyst of catalytic active metal, d. H. the part of the catalytic converter that does not • represent the catalytic converter support.

The preferred supported catalysts contain elemental ruthenium or ruthenium oxide from about 0.1 to about 10% by weight of the Catalyst, but if desired, catalysts with a higher active metal content can also be used Find.

The ruthenium-containing catalysts according to the invention have even comparatively moderate Temperatures and pressures have excellent effectiveness and give essentially 100 ° / yr Conversion of saccharides into polyvalent alcohols. The catalyst can be in the reaction mixture at a low concentration, such as about 0.0025 to 0.05 weight percent active catalyst component used as elemental ruthenium based on the weight of saccharide converted will. The catalysts of the invention can also be used in the hydrogenation processes according to FIG Invention can be used without intermediate regeneration.

The catalysts can be prepared by known methods. For example, you can first coat or impregnate the catalyst support with a solution of a ruthenium salt and then drying the impregnated material in contact with a stream of a reducing gas and heat to the decomposition temperature.

In general, when the process according to the invention is carried out in batches, the hydrogenating sugar in the insert of an autoclave and adds water and catalyst. The use is then closed and placed in a shaking autoclave, with hydrogen to the desired operating pressure brought, then the autoclave heated and shaken. After the desired reaction time the autoclave is cooled to room temperature and 4 <> opens and then discharged the reaction mixture. The catalyst is then removed from the reaction mixture separated and the reduced from the unreduced sugar separated. The response time can be some Minutes to about 24 hours or more, preferably about 1 to 6 hours.

example 1

In a series of experiments, grape sugar is hydrogenated to sorbitol using different amounts of a catalyst consisting of 5% elemental ruthenium on carbon. In these experiments, the sugar to be hydrogenated is weighed into the glass insert of an autoclave measuring 5.7 x 15.2 cm and then distilled water is added in an amount of 30 to 50 cm ³ . The desired amount of catalyst is precisely weighed and placed in the insert, then the insert is closed and placed in a high-pressure shaking autoclave of the Parr type with a capacity of 500 cm ³ . After assembly, the bomb is set to the desired operating pressure with hydrogen and the heating and shaking devices of the autoclave are switched on. The start of the reaction time is considered to be the point in time at which the autoclave has reached the desired operating temperature. After the desired reaction time, the shaking and heating devices are switched off, the bomb is cooled to room temperature and vented, the autoclave is opened and the glass insert containing the catalyst and the reaction mixture is removed. The catalyst is filtered off and the remaining reaction mixture is diluted in a volumetric flask. The amount of non-reduced sugar present, if any, is quantified with Fehling's solution using a different proportion of the solution in the volumetric flask.

The operating conditions and results are given in Table I.

Table I.

catalyst
(5% Ru-on-carbon sugar pressure temperature Time Hydrogenation G G atü ⁰ C hours ° / o 0.100 9 5.6 130 6th 100 0.200 37 5.6 130 24 100 0.100 90 14.1 135 24 *) 100 0400 45 14.1 130 10 100 0.050 35 14.1 140 16 100 0.025 25th 35.2 130 4th 100 0.025 35 35.2 130 16 100 0.025 40 70.3 130 4th 100 0.025 55 70.3 130 14th 100 0.025 80 70.3 130 24 100

*) The catalyst was reused twice.

Example 2

nation of ruthenium and platinum on carbon or aluminum oxide supports. as The general procedure for sugar is repeated, the hydrogenation of glucose is subordinated 1 except that thrown as catalysts. The reaction conditions and results Ruthenium-on-aluminum oxide and a combination 70 are the following:

Table II

catalyst glucose
G pressure
atü Average
temperature
⁰ C Hydrogenation
Vo 0.05 g
5% Ru on Al ₂ O ₃
0.05 g
1 »/ ο Pt, 4% Ru on C
0.05 g
1 ° / o Pt, 4 ° / o Ru to C
0.025 g
1% Pt, 4% Ru at C
0.05 g
1% Pt, 4% Ru at C 50
50
50
50
70 70.3
70.3
70.3
70.3
63.3 130
135
120
140
150 96.3
over 99.5
98.53
97.55
over 99

Example 3 _ao

This example is carried out according to the general procedure of Example 1. As sugar Cane sugar, fructose, malt sugar and milk sugar are hydrogenated using ruthenium on carbon as catalysts or a combination of ruthenium

and palladium on carbon are used. The disaccharides are cane sugar and lactose hydrolyzed and hydrogenated during the reaction to give the corresponding hexitols, in the case of malt sugar however, the maltitol is more easily formed. The working conditions and results are as follows:

catalyst sugar pressure
atü Time
hours temperature
⁰ C Hydrogenation
° / o 0.2 g
5 ° / o Ru at C
0.2 g
5% Ru on C
0.2 g
4% Ru, 1% Pd at C
0.2 g
4% Ru, 1% Pd at C
0.1g
5% Ru on C
0.2 g
5% Ru on C
0.2 g
5% Ru on C 50 g cane sugar
50 g cane sugar
50 g cane sugar
50 g cane sugar
25 g of fructose
50 g malt sugar
50 g milk sugar 70.3
70.3
71.7
70.3
66.8
70.3
70.3 2V ₂
6V2
3
5
4th
5
5 150
110
150
110
150
150
150 100
100
97
100
100
95
100

Example 4

This experiment is carried out according to the general procedure of Example 1. It will be under Use of 10 mg of ruthenium dioxide as a catalyst, 50 g of grape sugar hydrogenated, with one at a hydrogen pressure of 14.1 atm and a temperature of 135 ° C works. After 10 hours he hears "Hydrogen consumption on; that withdrawn from the autoclave Solution is 100% hydrogenated.

Example 5

Following the general procedure of Example 1, grape sugar is prepared using Platinum or palladium on carbon catalysts hydrogenated. When these catalysts are used for the corresponding reactions, one becomes essential lower effectiveness than achieved with the ruthenium-containing catalysts.

Working conditions and results are as follows:

catalyst sugar pressure
atü temperature
⁰ C Hydrogenation
° / o ig
5 ° / o Pt to C
ig
5% Pt on C
ig
50/0 Pd on C
ig
5% Pd on C 50 g of glucose
10 g of glucose
10 g of glucose
20 g of glucose 70.3
70.3
70.3
70.3 150
150
150
150 0
51.9
87
39

C ".rr 8! -» \ l- "CV

Claims (7)

EXAMPLE 6 Following the general procedure of Example 1, 25 g of grape sugar are dissolved in 50 cm3 of water and 1 g of Raney nickel is added. The mixture is then placed in an autoclave as above and pressurized to 70.3 atmospheres of hydrogen. The autoclave is shaken at a temperature of 135 ° C. for 5 hours. Under these conditions 15.4 g of the grape sugar are hydrogenated, which corresponds to 61.7% hydrogenation. There is considerable caramel formation. These results show that Raney nickel is also not nearly as effective in the hydrogenation process of the invention as the ruthenium catalyst of the invention. Pati ·:;. Τ claims. 1. Process for the production of polyhydric alcohols by hydrogenating sugars with Noble metal catalysts, characterized in that a ruthenium-containing catalyst is used. 2. The method according to claim 1, characterized in that the ruthenium content of the catalyst at least 50 percent by weight of the total catalytically active metal content of the catalyst. 3. The method according to claim 1 and 2, characterized in that the catalyst is metallic Ruthenium used on a carrier. 4. The method according to claim 1 to 3, characterized in that the catalyst used is ruthenium used in admixture with another platinum group metal. 5. The method according to claim 1 to 4, characterized in that there is a catalyst from the Group ruthenium and ruthenium oxide are used. 6. The method according to claim 1 to 5, characterized in that one is in aqueous solution is working. 7. The method according to claim 1 to 6, characterized in that one is preferably in the range from about 80 to 200 ° the treatment at elevated temperature and pressure, preferably im Performs range from 7 to 105 at. Considered publications:
German Patent Nos. 960 352, 892 590, 946; German Auslegeschrift No. 1 002 304;
U.S. Patent No. 2,209,055. © 909 649/416 11:59