US1215903A - Manufacture of glycols. - Google Patents

Description

"tJ'NllTED s'ra'rns Parana c ar on.

CORPORATION OF TEXAS.

MANUFACTURE OF GLYCOLS.

Patented Feb. 113, 11911 '3.

I ,2 5,903. Specification of Letters Patent. No Drawing.

To all whom it may concern:

Be it known that we BENJAMIN 'l. BROOKS and Inwnv I-IUMrnnnY, both citizens of the United States, residing in Pittsburgh, Allegheny county, State of Pennsylvania, have invented certain new and useful improvements in the Manufacture of (llycols; and we do hereby declare the following to be a full, clear, and exact description of the invention, such as Will enable ol hers skilled in the art to which it apportains to make and use the same.

This invention relates to the production of glycols or mixturesoi glycols from dichlorinated hydrocarbons of the ethylene series or mixtures thereof...

The dichlorinated hydrocarbons which are used for the production of the glycols, according to the present invention, may be the individual dichlorinated hydrocarbons such as ethylene dichlorid or Dutch liquor, or similar chlorids. The mixture of dichlorids which is produced from the unsaturated hydrocarbons of oil gas is of particular value in this process fol-the reason that it can be readily prepared from the oil gas by inexpensive methods and for the further reason that it permits the production therefrom by a single process of a mixture of glycols adapted for use to advantage directly as a mixture or for the production therefrom of the individual glycols.

()il gas, when suitably produced, is rich in olefins, and particularly in olelins of the ethylene series. The average oil gas may thus have from 33 to.43% of olefins, the remainder of the gas being of hydrogen and saturated hydrocarbons iii varying proportions. The olefins or unsaturated hydrocarbons of the oil gas consist principally of ethylene and propylene, but small amounts of other hydrocarbons such as butylene, amylene, benzol, etc., may also be present. The relative proportions of ethylene and propylene will also vary with different oil. gases depending upon the method of production of the gas, the material from Which produced, etc. The relative amounts of ethylene and propylene can also be varied and to a certain extent regulated by the method Application filed March 23, 1916. Serial No. 86,063.

of producing the oil the product obtained be correspondi n gl y unsaturated hydrocarbons from which the dichlorids are produced, the production of the oil gas and of the dichlorids therefrom can be effected in any suitable manner. It will be understood by those skilled in the art that various methods of producing the oil gas and of chlorinating the gas to produce the dichlorids are available for these purposes.

According to the present invention, the dichlorinated hydrocarbons of the ethylene series, separately or in admixture With each other, are caused to react with an alkali formate in the presence of an organic solvent such as methyl alcohol. The reaction of the dichlorinated hydrocarbon and the alkali form-ate results in the production of the formyl derivative or fol-mate of the corresponding hydrocarbon or hydrocarbons, alkali chlorid being at the same time set free. The formatesthus formed are acted upon by the methyl alcohol to give the corresponding glycol or glycols and methyl formate.

It has been heretofore proposed to produce glycols by conversion of the chlorids into acetates and recovery of the glycols from the diacetates. This process, however, requires expensive apparatus, a silver lining being commonly used to resist the glacial acetic acid utilized. The acetate method is, moreover, one in which small yields of the glycol are obtained, for example, yields of about 35% of the theoretical.

The novel method 01 the. present invention can be practised in simple and inexpensive apparatus and with yields as high as 80% or higher. Such yields are much higher than could a prion be expected, from analogous processes of the prior art.

A mixture of the dichlcrids such as is obtained from oil gas is heated with a slight excess (say 1 to 2 times the theoretical) of the alkali formate. We consider sodium formate better than the potassium for-mate for the reason that it is not hygroscopic and is cheaper and more easily obtained. An excess of say threeto five volumes of methyl alcohol is also added, and the resulting mixture is heated in an autoclave to a temperature of about 180 C. and under a maximum pressure of about 260 lbs. for about five or six hours. The pressure may be generated within the autoclave by heating to the temperature indicated. If thus the autoclave is two-thirds full, the pressure will attain a value of, for example, 200 to 260.1bs. temperature of the heating may be varied somewhat, for example, between 140 C. to 200 C.; and the pressure can also bevaried, for example, between 100 lbs. and 260 lbs.

The reaction is promoted by stirring or agitating the contents of the autoclave, and this agitation can, in practice, be obtained, for example, by rotating the autoclave.

It will be noted that the process is easily carried out in simple apparatus and with methyl alcohol as the solvent and as one of the reagents taking part in the operation. The process is thus much more advantageous than the acetate method, both in its method of procedure and in the increased results obtained.

After the operation is completed, the liquid contents are separated from any salt formed, by filtration, able manner, and the liquid mixture is then subjected to fractional distillation to recover therefrom the different constituents. The excess of methyl alcohol and the methyl formate are first removed and can be recovered for reuse or for further treatment. The glycols, having higher boiling points, are preferably distilled in cacao in order to avoid decomposition. Higher temperatures, such as would cause decomposition, are similarly avoided during the main reaction, for the same reason.

Where a mixture of glycols is obtained, as is the case where a mixture of dichlorinated hydrocarbons such as are obtained from oil gas is used as the starting material, this mixture can be directly used or it can be further fractionated and the separate glycols- (ethyleneglycol, propylene glycol, etc.,) recovered therefrom.

The methyl formate resulting from the rocess can be subjected to a suitable saponilication with caustic alkali and the alkali The or in any other suit- It "will thus be seen that the process is one of notable econom in that expensive reagents are not re uired and in that'the'alkali formate and t e methyl alcohol are to a greater or less extent recovered ina form suitable for re-use.

As abovepointed out, the mixture of die chlorinated hydrocarbons obtained from oil gas is of particular value in the practice of the invention for the reaso amo others, that the resulting mixture 0 glyco is produced directly and is available for use as such or as a source of the individual glycols.

When amixture of the dichlorina ed hydrocarbons is thus-used, the formation of the different gl cols proceeds smoothly and simultaneous with the resulting production of the glyco mixture.

Whatwe claim is:

l. The method of producing glycols. from dichlorinated ethylene hydrocarbons which comprises subjecting such hydrocarbons'to reaction with an alkali formats in the presence of an alcohol; substantially as described. -2. The method of producing glycols from dichlorinated ethylene hydrocarbons, which comprises heating the same under pressure with an alkali formate and an alcohol; substantially as described.

3. The method of producing glycols from dichlorinated ethylene hydrocarbons, which comprises heating the same to a temperature of about 140 to 200 C. and a'presure of 100 to 260 lbs. together with an alkali formate and an alcohol; substantially 'as described.

4. The method of producin lycols from dichlorinatecLethylene hydrocasi comprises subjecting the same to the action of sodium formate and methyl alcohol; substantially-as described. I

5. The method of producing lycols from dichlorinated ethylene hydrocafiions, which comprises heating the same to a'high temperature and pressure in the presence of sodium formate and methyl alcohol; substantially as described. 4

6. The method of producing a' mixture of glycols from a mixture of dichlorinated ethylene hydrocarbons, which comprises subjecting the mixture of dichlorinated hydrocarbons to reaction with an alkali formate and an alcohol; substantially as described.

7. The method of converting dichlorinated hydrocarbons into diformates, which comprises heating the same with alkali format'es in the presence of an organic solvent; substantially as described.

8. The method of converting diform l derivatives of hydrocarbons into glyco ons, which 9. The method of producing glycols from ering the alkali formate for further use; dichlorinated hydrocarbons, which comsubstantially as described. prises subjecting the dichlorinated hydro- In testimony whereof we our signa- 10 carbons to reaction with an alkali formate tures. and an alcohol and thereby producing the glycols and the formate of the alcohol, and BENJAMIN BROOKS. saponifying the formate and thereby recov- IRWIN i I i 2': a