DE1944277A1 - Process for the production of butane derivatives - Google Patents

Description

Badische Anilin- A Soda-Fabrik AG * ττ *, /

Our reference: O.Z. 26 339 Bk / Be 6700 Ludwigshafen, August 29, 1969

Process for the production of butane derivatives

The invention relates to a process for the preparation of butane derivatives by electrolysis of olefinically unsaturated ones Links.

It is known from Chemical Reviews 68 (1968), page 471 that by electrolysis of styrene in the presence of methanol and Sodium methylate, styrene glycol dimethyl ether, oC-methoxyethylbenzene, ß-methoxyethylbenzene and small amounts of meso 1,4-dimethoxy-2,3-diphenylbutane receives. The electrolysis according to the method described is carried out on platinum electrodes.

It has now been found that one can use butane derivatives of the general formula

R- | ρ ρ R-j

\ ι ² | 2 /

^ CH - CH - CH - CH ^ I,

R R

in which R denotes an aromatic radical or an alkoxy group and R ₁ denotes a hydrogen atom or an alkoxy group or alkyl group and R ₂ denotes a hydrogen atom or an alkyl group and R-, and R ₂ together with the carbon atoms they substitute a 5- can denote up to 12-membered cycloaliphatic ring and if R denotes an aromatic radical, R and R ₂ together with the carbon atoms which they substitute can form a 5- to 6-membered cycloaliphatic ring by electrolysis of olefinically unsaturated compounds of the general formula

R ₁ R ₂

^ c. df

400/69 - * 2 -

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in. The R, R-, and Rp have the meaning given, in the presence of lower aliphatic alcohols and a conductive salt is advantageously obtained if graphite electrodes are used as electrodes used.

The new process makes it possible to produce a large number of 1,4-substituted Produce butane derivatives in good yields. The method also has the advantage that it can be carried out easily.

The new process is noteworthy in that it was not to be expected that by using graphite electrodes the The electrolysis of styrene proceeds differently than on platinum electrodes (cf. Chemical Reviews 68 (1968), page 471).

In. the "preferred starting materials of the formula II" mean a phenyl group which can have 1 to 2 substituents such as alkyl radicals with 1 to 4 carbon atoms, chlorine or bromine atoms or alkoxy groups with 1 to 4 carbon atoms, or an alkoxy group with 1 to 4 carbon atoms In _{the preferred starting materials, R 1} stands for a hydrogen atom, an alkoxy group or alkyl group with 1 to 4 carbon atoms. R ₂ stands for a hydrogen atom or an alkyl group with 1 to 4 carbon atoms Formula II together with the carbon atoms which they substitute also denote a 5- to 12-membered cycloaliphatic ring, and if R denotes a phenyl radical, R and R «together with the carbon atoms which they substitute can form a 5-membered cycloaliphatic ring Form .. Starting materials of the formula II in which R is a phenyl radical or an alkoxy group are particularly preferred with 1 to 4 carbon atoms and R ₁ © in hydrogen atom, an alkoxy group or alkyl group with 1 to 4 carbon atoms, where R-, and R «together with the carbon atoms they substitute, also a 6- to 8-membered group can mean cycloaliphatic ring. Suitable starting materials are, for example, vinyl methyl ether, vinyl ethyl ether, vinyl n-butyl ether, styrene, p-ethylstyrene, p-chlorostyrene, indane or methoxyoyolohexene,

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The electrolysis is carried out in the presence of lower aliphatic Alcohols carried out. Alkanols with 1 to 3 carbon atoms, in particular methanol or ethanol, are preferably used. Partly one uses per mole of olefinically unsaturated Compound 1 to 5 moles of alcohol. Particularly good results are obtained if one mole of olefinically unsaturated compound 2 to 3 moles of alcohol are also used.

Electrolysis is used to improve conductivity in the presence carried out a conductive salt. Alkali metal iodides or alkali metal perchlorates and alkali metal methylates have proven particularly useful as conductive salts. Because of their easy technical accessibility, sodium iodide, sodium perchlorate or sodium methylate are particularly preferred used as conductive salt. The mixture to be electrolyzed advantageously contains 0.2 to 10 percent by weight, in particular .0.7 to 5 percent by weight, conductive salt.

It has proven advantageous to use electrolysis at anode voltages from +0.2 to +1.8 V, in particular from +0.5 to +1.4 V, (measured against a silver / silver chloride electrode)

2 2

and current densities from 25 mA / cm to 75 mA / cm. In general, temperatures from -40 to +80 G are used. Particularly good results are obtained at temperatures from -20 to +40 ⁰ G.

An essential feature of the invention is that the electrolysis is carried out on graphite electrodes. In general one uses the commercially available ones suitable for electrolysis purposes Graphite electrodes. Graphite electrodes have proven particularly useful P 127 from Sigri, Meitingen near Augsburg.

The method according to the invention is carried out, for example, by placing in an electrolysis vessel with graphite electrodes • is equipped, olefinically unsaturated compounds of the formula II and the alcohols mentioned in the ratio mentioned submits, adds the specified amount of one of the electrolyte salts described and anode voltages at the temperatures described and current densities that perform electrolysis. It is possible to separate the electrolytic cell with a diaphragm. Advantage-

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The electrolysis is carried out without a diaphragm. In general the electrolysis is carried out until 0.1 to 0.5 Faraday are consumed. The reaction mixture is then prepared using known methods, e.g. by fractional distillation worked up.

The butane derivatives produced by the process of the invention are suitable e.g. for the production of 1,4-dicarbonyl compounds. Furthermore, the substances produced according to the invention can be removed from the substances prepared according to the invention by splitting off methanol, for example by treatment with phosphoric acid, butadiene derivatives.

example 1

A solution of 1.4 g of sodium iodide in 120 ml of methanol and 80 ml of vinyl ethyl ether is measured at -5 0, a current density of 40 mA / cm and an anode voltage of +0.6 to +0.9 "V (against a silver / Silver chloride electrode), on graphite electrodes P (Sigri, Meitingen), which are attached at a distance of 10 mm. The mixture to be electrolyzed is circulated during the electrolysis. The electrolysis is carried out until 0.232 Faraday are consumed. Then the methanol is distilled off and the residue is treated with 20 ml of water and then extracted. the extract is fractionally distilled after evaporation of the ether. this gives 12.3 gl, 4-diethoxy-l, 4-dimethoxybutane of boiling point 93 to 95 ⁰ C in 14 mm Hg.

Example 2

A solution of 10 g of sodium perchlorate and 0.2 g of sodium in 120 ml of methanol and 80 ml of styrene at 20 degrees has an anode voltage of +1.1 V and a current density of 75 mA / cm ² as described in Example 1 until it is consumed of 0.216 Faraday. The mixture obtained is worked up as described in Example 1. Fractional distillation gives 18.7 g of 4-diphenyl-1,4-dimethoxybutane with a boiling point of 125 to 135 ^° C. at 0.01 mm Hg and a melting point of 81 to 83 ^° C. The current yield is 65 °.

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Example 3

A solution of 25 g (2) Äthoxycyclohexene1,2) and 0.4 g sodium in 30 ml methanol is at 10 ⁰ G, an anode voltage of

+0.5 V and a current density of 37 mA / cm as described in Example 1 up to a consumption of 0.1 Faraday. The methanol and the excess ethoxycyclohexene are then distilled off. The residue is treated for 2 hours with a solution of 1 η sulfuric acid in methanol. By fractional distillation, 2.6 g is obtained (corresponding to 27 i> current yield) of 2,2-Dicyclohexanon of boiling point 92 to 94 ⁰ C at 0.01 mm Hg.

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Claims (1)

- 6 - O.Z. 26 339 claim Process for the preparation of butane derivatives of the general formula Rn TJ TJ TJ x ¹ * ² f ² Z ¹ .CH - CH - GH - CH I, R R in which R is an aromatic radical or an alkoxy group and R ^ is a hydrogen atom, an alkoxy or alkyl group, R _{2 is} a hydrogen atom or an alkyl group and R-, and R ₂ together with the carbon atoms they substitute, one Can denote 5- to 12-membered cycloaliphatic ring and if R denotes an aromatic radical, R and R ₂ together with the carbon atoms which they substitute can denote a 5- or 6-membered cycloaliphatic ring, by electrolysis of olefinically unsaturated compounds general formula R-, R ₂ - CH II, in which R, R ₁ and R _{2 have} the meaning given, in the presence of lower aliphatic alcohols and a conductive salt, which means that graphite electrodes are used for the electrolysis. Badisoh «Anilin-A Soda-Fabrik AG