DE2431035A1 - PROCESS FOR THE PRODUCTION OF CATECHIN - Google Patents

Description

Process for the production of catechol

In US application No. 375 195 of June 29, 1973, the production of 1,2-epoxy-3-hydroxycyclohexane. In this it is stated that epoxy alcohols can generally be obtained from olefins. The "starting product used in the process according to the invention can thus consist of cyclohexene by oxidation in the presence of a catalyst comprising an anionic support, e.g. an X zeolite, which comprises two different contains valence-bound metals, preferably cobalt and vanadium. *

The present invention relates to a new process for the production of catechol and resorcinol.

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The invention relates in particular to a process for the production of pyrocatechol alone or in a mixture with resorcinol, by taking 1,2-epoxy-3-hydroxycyclohexane (HEC) Is dehydrogenated using a transition metal catalyst.

Pyrocatechol, ie, 1,2-dihydroxybenzene, is a well-known chemical intermediate used in the manufacture of pesticides, antioxidants, and the like, as well as pharmaceuticals and vanillin and papaverine. Pyrocatechol has hitherto been produced, for example, by hydroxylation of phenol with Ή-η ?? ' Sulphonation ^of benzene and subsequent alkali melt of the alkali sulphonate or produced by oxidation of o-diisopropylbenzene. Each of these methods are costly and endless.

Resorcinol is also an intermediate product that is used in the manufacture of wood and rubber adhesives, cosmetic paints and the like is used.

According to the invention, pyrocatechol and, in some cases, resorcinol, depending on the catalyst used following reaction scheme:

OH

i no -

OH _2H,

OH

C.

OH

Group VIII transition metal catalyst

The production of catechol and resorcinol from HEC can suitably be carried out either in the liquid or vapor phase, with a dehydrogenation catalyst

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Group VIII transition metal is used will. Preferred catalysts are palladium, platinum and ruthenium in the form of platinum or palladium black or of platinum, ruthenium or palladium on an inert one Carriers, examples of which are known preparations such as Pd on aluminum oxide, Pd on carbon, Pd on kieselguhr and the like, the amount of platinum, ruthenium or palladium present being about 0.5-100 % By weight, based on the weight of the carrier. Osmium, iridium and rhodium are also suitable, either on their own or applied to a carrier. Alternatively can also use any other known dehydrogenation catalysts can be used that contain transition metal components.

The amount of catalyst used will vary accordingly the known dehydration measures depending on whether liquid or Vapor phase conditions are observed. Although the amount is not critical, it should be Working in the liquid phase, the catalyst advantageously in amounts of about 1 to 10 wt .-%, based on the weight of the HEC starting material.

Solvents that can be used when working in the liquid phase are, for example, high-boiling alkyl or aralkyl hydrocarbons, such as phenyldodecane and dodecane. The reaction temperature is expediently about 175 to 350 ^° C., preferably 200 to 300 ^° C.

Alternatively, the dehydration can also be carried out in the vapor phase. This is suitably described in the You can also reach the HEC through a pipe downwards conducts that with a transition metal catalyst

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Group VIII and an inert refractory material such as Corhart (Corhart Industries, Inc.). The temperature is approximately from 250 to 400 ° C, preferably 300 to 35O ⁰ C, at which temperature the HEC is a vapor. The hourly space velocity (GSRG) is about 0.1 to 10.0, preferably about 0.5 to 1.5.

That in the presence of some catalysts, in particular Benzene diol formed by palladium and palladium deposited on a support consists mainly of or exclusively from pyrocatechol or from pyrocatechol precursors, such as cis- and trans-1,2-cyclohexanediol, 1-hydroxycyclohexanone and 1,2-cyclohexanedione. Against be with other catalysts, especially ruthenium catalysts, mixtures of benzene diols in the vapor phase, i.e. pyrocatechol, and formed from resorcinol. In these cases, however, the catechol is still present when resorcinol is formed the main product.

It can thus be seen that in each case regardless of the The catalyst used is catechol, while resorcinol is only formed with selected transition metal catalysts is formed. Routine testing determines whether or not resorcinol is formed by a given catalyst regarding the presence in the reaction mixture, e.g. by gas chromatographic analysis, to be determined.

example 1

To 10.0 g HEC is added 1.0 g Palladiumschwarζ and the mixture is stirred under nitrogen for 10 hrs at 200 ⁰ C. Hydrogen is released and the catechol becomes

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formed with a yield of 61? ό. Other products include cis-i ^ -cyclohexanediol, 26%, 2-cyclohexen-i-ol, 10 ^, phenol, 2%, and traces of unidentified materials.

Example 2

To 5.0 g HEC 10, dissolved in phenyldodecane, ml, 1.0 g of palladium black is added and the mixture is stirred under nitrogen for 20 hours at 20O ⁰ C. Hydrogen is released and the pyrocate is formed with a yield of 56% . By-products are cis-1,2-cyclohexanediol, 2-cyclohexen-i-ol, phenol and traces of unidentified materials.

Example 3

3.0 g of HEC are routed (30 cm 1 cm diameter, length) at 300 ⁰ C downwardly through a glass tube packed with 3 g of 10% palladium on carbon, mixed with Corhart, is filled. The GSRG is 1.0. Pyrocate is selectively formed in a high yield. By-products are 1,2-cyclohexanediol, phenol, 2-cyclohexene-i-oil and unidentified materials.

Example 4

A number of noble metal catalysts is in a PuIs microreactor at 270 to 300 ⁰ C under a pressure of 3.52 atmospheres of a mixture of hydrogen and helium with a

■ χ

Flow rate of 50 cm / min used. The sample, HEC, is injected into the catalyst bed and the product mixture are transported by the gas flow directly to a gas chromatograph and analyzed there. at

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Using k% Pt on graphite, the pyrocatechol yield is 26% and no resorcinol is found. When using k% Ru on graphite, a mixture of pyrocatechol (yield 35%) and resorcinol (yield 2090) is formed. Under these conditions, palladium black gives a 2% yield of pyrocatechol and no detectable resorcinol.

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vr

Claims (9)

Patent a η s ρ r ü c h e 1. Process for the production of catechol, thereby It is known that 1,2-epoxy-3-hydroxycyclohexane is used Dehydrogenated in the presence of a Group VIII transition metal catalyst. 2. The method according to claim 1, characterized in that g e k e η η ζ e i c h η e t that the product is a mixture of Contains catechol and resorcinol. 3. The method according to claim 1, characterized in that g e k e η η ζ e i c h η et that the catalyst used is palladium, Platinum or ruthenium used. 4. The method according to claim 3, characterized in that g e k e η n-drawing η e t that one is the palladium, platinum or Ruthenium used in the form deposited on aluminum oxide, carbon, diatomite or graphite. 5. The method according to claim 1, characterized in that g e k e η η ze i c h η e t that the catalyst used is osmium, iridium or rhodium. 6. The method according to claim 5> thereby g e k e η η ze i ch η et that one osmium, iridium or rhodium used in the form deposited on aluminum oxide, carbon, diatomite or graphite. 7. A method according to claim 1, characterized geke η η ζ e ic h η et that one to 35O performs the dehydrogenation in the liquid phase at a temperature of about 175 ⁰ C. ; 409883/1378 - ff - 8. The method according to claim 1, characterized in that the catalyst is used in amounts of about 1 to 10 wt. % _F based on the weight of the HEC starting material. 9. The method according to claim 1, characterized in that the reaction is carried out in the vapor phase carried out by keeping the cyclohexane materials at a temperature of about 300 to 400 ° C and a weight hourly space velocity from about 0.1 to 10.0 passes through. 409883/1378