DE1217940B - Production of aromatically substituted ethers - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY GERMAN JfflfWWl · PATENT OFFICE Int. Cl .:

C 07c

EDITORIAL

German class: 12 ο-5/09

Number: 1217 940

File number: M 49675 IV b / 12 ο

Filing date: July 14, 1961

Opening day: June 2, 1966

Aromatic ethers, such as ethyl phenyl ethyl ether, are stable compounds, often relatively volatile liquids, which are in suitable Cases can be used as solvents and plasticizers. Ethers of this type can for example from styrene and an alcohol, such as ethyl alcohol, by reacting in the presence of a concentrated Sulfuric acid or any other strong acid. However, this method has the Disadvantage that an acid such as sulfuric acid with the polymerization of the styrene to form polymers high molecular weight, which not only is difficult to remove from the desired ether but which result in a loss of styrene.

It has now become an effective method of making aromatically substituted ethers from styrene and other vinyl compounds in which the above disadvantage is avoided.

The present invention accordingly relates to a process for the preparation of aromatically substituted Ethers, by reacting a vinyl aromatic compound with an alcohol in the presence an acidic catalyst and is characterized in that the salt is a further catalyst Metal, which can be present in at least two valence levels, is used.

The vinyl aromatic compounds which can be used in the process according to the invention are those in which a vinyl group is directly linked to a carbon atom of a carbocyclic aromatic nucleus is connected. The aromatic nucleus can be a single ring of a carbon atom such as Be in styrene, or it can be present on a di-, tri- or poly-core-linked ring system be, as for example in vinylnaphthalene, vinylindene, vinylanthracene or vinylchrysen.

The vinyl aromatic compound may be a hydrocarbon or a compound derived from a hydrocarbon by replacing one or more hydrogen atoms of an aromatic one Nucleus was derived through a substituent. The substituent or substituents can im be stored in the same core as a vinyl group or in a different core and are in general those which occur essentially during the reaction of the vinyl aromatic group with the alcohol remain unchanged. Such substituents include hydrocarbon groups, for example alkyl, Cycloalkyl, aralkyl and aryl groups, of which methyl, ethyl, n-propyl, isopropyl, n-butyl, s-butyl, isoamyl, hexyl, octyl, decyl, hexadecyl, Production of aromatic substituted ethers

Applicant:

Monsanto Chemicals Limited, London

Representative:

Dr. M. Owl

and Dipl.-Chem. Dr. rer. nat. W. J. Berg,

Patent Attorneys, Munich 2, Hilblestr. 20th

Named as inventor:
Robert James Stephenson,
Llanyravon, Cwmbran, Monmouthshire
(Great Britain)

Claimed priority:

Great Britain July 15, 1960 (24 744) °

Cyclopentyl, cyclohexyl, methylcyclohexyl, benzyl, / I-phenylethyl, phenyl, tolyl and xylyl groups Are representatives; Ether groups, e.g. B. alkoxy, cycloalkoxy, aralkoxy and aryloxy groups, of which methoxy, ethoxy, propoxy, butoxy, hexyloxy, decyloxy, tetradecyloxy, cyclohexyloxy, Benzyloxy and phenoxy groups are representatives; Halogen atoms such as chlorine and bromine; and Nitro groups. The substituent can also be a vinyl group, and where a compound is more than one Contains vinyl group, each can be reacted with the alcohol to di-, tri- or in appropriate Cases to yield polyether.

Specific examples of vinyl aromatic compounds used in the process of the present invention can be used are styrene, ο-, m- and p-vinyltoluene, o-, m- and p-vinylethylbenzene, p-vinylphenylcyclohexane, p-benzylstyrene, p-methylp'-vinylbiphenyl, o-, m- and p-chlorostyrene, o-, m- and p-nitrostyrene, 3-methyl-4-nitrostyrene, o-, m- and p-divinylbenzene, 1- and 2-vinylnaphthalene, l-vinyl-5-methylnaphthalene, 2-vinyl-4-methoxynaphthalene, 2-vinyl-6-ethoxynaphthalene, 1-vinyl-7,8-dibromonaphthalene and 2-vinylanthracene.

A wide range of alcohols can be used; these are preferably both primary like secondary alcohols, but a tertiary alcohol can also be used in some cases. The alcohols include those of the aliphatic

609 577/457

3 4

Rows with either straight or branched The ratio of metal salt, which in relation to Carbon chains one where the chain is completely saturated due to the amount of vinyl aromatic compounds be or one or more multiple carbon uses can be made of large amounts, may contain bonds or in which, for example, as much as 0.5 mol per mol of vinyl the carbon chain through other atoms, such as 5 aromatic compound up to as little as 0.002 or Oxygen or sulfur, is interrupted. Examples even 0.0002 moles per mole of the vinyl aromatic vervon such aliphatic alcohols involve bonding, alternating. In general, a molar Methanol, ethanol, n- and isopropanol, n-, iso-, s- ratio in the range from 0.005: 1 to 0.1: 1 and t-butanol, the amyl and hexyl alcohols, lauryl, drawn, for example 0.007: 1, 0.01: 1, 0.02: 1, Myristyl and cetyl alcohols, allyl alcohol, 3-butene-io 0.03: 1 or 0.05: 1.

1-ol-, 4-penten-2-ol-, oleyl alcohol, ethylene glycol- An excess of both the vinylaromatic vermonobutyl ether and diethylene glycol monoethyl bond as well as alcohol can be used in relation to the ether. The aliphatic alcohols include the others used, or they can be used in Aheyclic alcohols, for example cyclopentanone, be present in equivalent amounts. It will be in Cyclohexanol, 2-ethylcyclohexanol and aralkyl alcohol - 15 generally preferred that the amount of for example benzyl alcohol and core-substituted alcohol at least equivalent to the amount tuated benzyl alcohols. the vinyl aromatic compound is because difficult-

The metal salt, which is in the potencies according to the invention, associated with the inclination of any Method that can be used includes, for example, excess of the latter to polymerize, then extensively the halides, in particular the chlorides 20 are avoided. The molar ratio of and bromides, sulfates, sulfides, acetates and p-toluene- 'alcohol to vinyl aromatic compound can so sulfonates of metals, which are as high as 10: 1 in at least two but smaller proportions, Valence levels are able to be present; for example within the range 5: 1 to 1: 1 Examples of such are copper, cobalt, mercury are generally satisfactory, and have been silver, titanium, zirconium, chromium, manganese and iron. 25 with molar ratios of 3.6: 1, 2.5: 1 and 1.2: 1 The salt can be one in which the metal performs well. In general, the is present in its lowest valence level, reaction by heating a mixture of vinyl or one in which the metal is in a higher aromatic compound, alcohol, metal salt and Value level is present. Optionally, an acidic catalyst, for example in the case of a Tempe mixture of such salts can be used. So is carried out 30 temperature in the range of 40 to 200 ° C, when the metal is copper and for example the 'Preferably the reaction temperature should be within Salt a chloride, it is possible to use copper (II) chloride alone, the limits are from 80 to 175 ° C, and a Tempe-KupferQQ-chloride alone or a mixture of temperature between 100 and 150 ° C was considered special Copper (I) and copper (II) chloride found suitable to use.

Cobalt (II) - and cobalt (III) salts, for example Ko- 35 When the vinyl aromatic compound or the balt (II) chloride, and mercury (II) and mercury alcohol have a normal boiling point within the silver (I) salts, for example mercury (II) acetate, have the desired temperature range, it is possible can be used in the same way. Im all-sufficient, simply reflux the mixture Commonly, the copper salts are very effective at cooking at atmospheric pressure. In other cases sators. 40, a reflux temperature within the

The salt is usually in the form of a powdery solid.

body used, however, in some cases there would be an inert diluent, for example

be introduced as a complex. A copper (T) - a petroleum fraction or by working with

Halide can be used, for example, as copper (I) halogen pressures above or below atmospheric pressure

acid complex are introduced. 45 can be obtained. It is of course not necessary

The in the process according to the invention that the mixture is refluxed and used acidic catalyst is preferably a water - if desired, the reaction temperature can be a single substance halide, for example hydrogen chloride or by regulating the reaction vessel to hydrogen bromide, and it is usually run as one Heat to be controlled.
Solution in alcohol is introduced into the reaction system. 50 The time required to complete the reaction, optionally in suitable cases of the acidic compound, depends on various factors, catalyst as an addition product with the vinyl- which the reactivities and the relative amounts of the aromatic compound are added, for example- vinyl aromatic compound and alcohol wise as α-methylbenzyl chloride when the vinyl and the amount and formulation of aromatic compound used is styrene and include the acidic catalyst. So the length of time the catalyst is hydrogen chloride. Another less reaction from possibly 1 hour to nearly preferred method is to vary the acidic 50 hours. In general, a time catalyst as a concentrated aqueous solution lasting from 10 to 20 hours is sufficient to introduce. optimal length of time for any particular response

The molar ratio of metal salt to acidic 60 is easy to determine. In special cases, for example

Catalyst, which wise to carry out the process if you run the process continuously

Can be used in a wide range, it may be more appropriate to the reaction

change from approximately 1:50 to approximately 1: 0.25. to terminate before the maximum output level

The preferred ratio range is 1:25 until the prey is reached, and the unchanged starting

1: 0.5, and mixtures with ratios within 65 materials' separate and recycle

in the range 1:20 to 1: 0.8, for example 1:15.

1:10, 1: 7.5, 1: 4, 1: 3, 1: 2.5 and 1: 1 were

Used success. reaction mixture removed by fractional distillation

be separated. The invention is illustrated by the following examples.

example 1

This example describes the preparation of ethyl phenyl ethyl ether from styrene and ethanol using a copper salt as a catalyst. Hydrogen chloride gas was bubbled into 138O g of ethanol until 55 g was absorbed. 1040 g of styrene and 55 g of powdered copper (I) chloride were added and the mixture was refluxed for 16 hours. After cooling, the mixture was diluted with approximately half its volume with diethyl ether and then washed with sufficiently dilute aqueous ammonium hydroxide solution (approximately 2 normal) in order to remove the copper salts. The organic layer was separated and, after drying over anhydrous magnesium sulfate, distilled through a fractionation column, first at atmospheric pressure to remove the diethyl ether and unreacted ethanol, and then under reduced pressure. There were 940 g of ethyl-a-phenylethyl ether as a fraction having a boiling range 100-107 ⁰ C at a pressure of 65 mm of mercury.

Example 2

This example describes the production of n-butyl-a-phenylethyl ether from styrene and n-butanol using a copper catalyst.

A suspension of 20 g of powdered copper chloride in 1040 g of styrene was added to a solution of 55 g of hydrogen chloride in 1850 g of n-butanol and the mixture was refluxed for 17 hours. The reaction mixture was then distilled through a fractionation column at a pressure of 8 mm of mercury. Unchanged n-butanol and styrene together with some a-methylbenzyl chloride, was collected as a forecut over the temperature range of 40 to 90 ⁰ C. The main fraction, which consisted of n-butyl-a-phenylethyl ether, was collected in the temperature range from 90 to 97 ° C. and weighed 1250 g.

Example3

This example describes the preparation of n-butyl - «- phenylethyl ether using a Cobalt salt as a catalyst.

A suspension of 2.6 g of powdery cobalt OQ chloride in 104 g of styrene was added to a solution of 5.5 g of hydrogen chloride in 185 g of n-butanol and the mixture was refluxed for 3 hours. The reaction mixture was then distilled through a fractionation column at a pressure of 10 mm of mercury. An amount of non-reactive starting materials distilled first, and this was followed by a fraction of 80 g, which consisted of n-butyl-a-phenylethyl-ether with a boiling range 92-98 ⁰ C.

Example 4

Example 3 was repeated using 6.4 g of mercury (II) acetate instead of 2.6 g Cobalt (II) chloride. There were 85.4 g of n-butyl-a-phenylethyl ether obtain.

Example 5

This example describes the preparation of n-butoxyethyl-a-phenylethyl ether from styrene and ethylene glycol mono-n-butyl ether using a copper salt as a catalyst.
__ A solution of 55 g of hydrogen chloride in 2360 g of ethylene glycol mono-n-butyl ether was added to a suspension of 50 g of pulverized copper (I) chloride in 1040 g of styrene. The mixture was then stirred ^{at 110 ° C. for hours.} After cooling, the product was washed with sufficiently dilute aqueous ammonium hydroxide solution (approximately 2 normal) to remove the copper salts. The organic layer was separated off and distilled under reduced pressure and gave a small amount of water as a preliminary fraction, together with somewhat unchanged starting materials and g main fraction with a boiling range of up to 144 ° C. at a pressure of 30 mm of mercury. The latter fraction was essentially pure n-butoxy-ethyl-a-phenylethyl ether.

Claims (8)

Patent claims: 1. Process for the preparation of aromatically substituted ethers by reacting a vinyl aromatic Combination with an alcohol in the presence of an acidic catalyst, thereby characterized in that as a further catalyst, the salt of a metal, which in at least two weighting levels can exist is used. 2. The method according to claim 1, characterized in that that the vinyl aromatic compound is a hydrocarbon, preferably styrene. 3. A method for producing an aromatic ether according to any one of claims 1 and 2, characterized characterized in that the alcohol is an aliphatic primary or secondary or cycloaliphatic, preferably methyl, ethyl, propyl, butyl, amyl, hexyl, lauryl, cyclohexyl or Is benzyl alcohol. 4. The method according to any one of claims 1 to 3, characterized in that the acidic catalyst is a hydrogen halide. 5. The method according to any one of claims 1 to 4, characterized in that the salt of the metal is a salt of copper, cobalt, mercury, titanium, zirconium, chromium, manganese or iron. 6. The method according to any one of claims 1 to 5, characterized in that the salt of the metal is a halide, sulfate, sulfide or acetate. 7. The method according to any one of claims 1 to 6, characterized in that the molar ratio of the metal salt to the acidic catalyst is between 1:50 and 1: 0.25. 8. The method according to any one of claims 1 to 7, characterized in that between them 0.002 and 0.5MoI metal salt per mole of vinyl aromatic Connection is used. Considered publications:
U.S. Patent No. 2,139,359;
French patent specification No. 882 460. 609 577/457 5.66 © Bundesdruckerei Berlin