US1947989A - Method of oxidizing hydrocarbons - Google Patents

Description

Patented Feb. 20, 1934 PATENT OFFICE METHOD OF OXIDIZING HYDROCARBONS Theodor Hellthaler, Granschutz, and Erich Peter,

Webau, Germany, assignors to firm A. Riebecksche Halle. Germany Montanwerke Aktiengesellschaft,

No Drawing. Application October 8, 1930, Serial No. 487,381, and in Germany June 20, 1928 16 Claims. (01. 269-98) Our invention refers to the recovery of valuable products of oxidation from hydrocarbons, more especially such as parafiine, waxes and substances of a similar constitution and has for one of its objects to allow the recovery of products which hitherto could not be obtained by similar processes and to be more etlicient than the processes hitherto devised.

As is well known to those skilled in the art, when subjecting parafline and other hydrocarbons including wax and similar substances to an oxidizing treatment with oxygen or gases containing same, such as for instance air, mixtures of products of oxidation are formed, the chemical composition of which depends from the character of the starting materials, from the conditions under which oxidation has taken place and from the presence or absence of catalysts. The products of oxidation substantially consist of fatty 20 acids, while alcohols and other compounds containing hydroxyl have been obtained only in comparatively small percentages.

The method according to the present invention allows recovering valuable products of oxidation rich in alcohols and/or the esters thereof. It is based on the discovery that in the oxidizing treatment of hydrocarbons instead of fatty acids, alcohols and/or their esters are obtained, if the oxidation is carried out in the presence of boric acid, a mixture of boric and acetic acids or an anhydride of these acids. Apparently these acids and anhydrides in contradistinction to all hitherto used catalysts or fatty acids are capable of protecting the alcohols which are formed against a further attack by the oxidizing agents.

The acids or anhydrides mentioned above as exerting a protective action are added to the reaction mass either before or after the reaction has started and either at once or gradually.

Boric acid can be replaced entirely or partly by similar acids such as arsenious or phosphorous acid, while acetic acid can be replaced by other organic acids.

The new process is capable of application in all cases where hydrocarbons can be oxidized in the absence of boric acid or the like. Preferably the reaction is carried through at a temperature of about 160-200" C; in the presence or absence of filling bodies and catalysts and at atmospheric or higher pressure. the present invention a fair yield of esters of boric acid or the other acids used with the alcohols which would otherwise be formed only temporarily 'is obtained and if desired these esters can be converted into the corresponding alcohols by In such case according to,

boiling the acids with water or in some other way.

We have further discovered that the esters of the boric or other acids can be separated from the parafiin-hydrocarbons, which have not.un-

.dergone oxidation, by treating the crude oxidation products with suitable solvents, such as for instance alcohol, thereby affecting a purification of the products.

The esters which are isolated in this manner still contain the fatty acids formed by the oxidation, because these acids are also soluble in alcohol. In order to obtain the esters as free from fatty acids as possible, the crude products of oxidation or the esters, which have been separated already from the non-oxidized constituents, can be treated with aliphatic hydrocarbons, more especially with petroleum ether and gasoline or with similar acting solvents, such as for instance benzene. This treatment can either be carried out in such manner, that the crude products of oxidation or the mixture of esters and fatty acids isolated therefrom are dissolved by heating in one of the solvents above mentioned, the solution being allowed to cool down and the esters of boric, arsenious or phosphorous acid, which have separated out, being separated from the liquor by filtration. One may however also lixiviate in an extraction apparatus the crude products with these solvents at a low or moderately elevated temperature. When proceeding in this latter manner the crude products to be extracted are preferably mixed with distributing bodies, such as sand, fullers earth, kieselguhr or the like, and after extraction these bodies are removed again by dissolution. If the oxidation products are treated with gasoline or petrol ether there is obtained in the extract or filtrate the greater quantity of the hydrocarbons which has not undergone oxidation and also the fatty acids which may have formed, while the esters and in certain cases also small quantities of high melting paraflines are retained on the filter or remain over as a residue from the extraction.

The alcohols obtained from the esters by decomposition with water or in some other way may if desired be freed from comparatively small quantities of fatty acids still present by some well known method, for instance by saponifying the fatty acids and extracting the alcohols from the soap solution with ether. Inthis manner new and valuable products can be obtained, which are capable of use for many purposes.

Thus for instance the crude oxidation product polishing wax substitutes, dubbings, machine of paramne is distinguished from the original parafiine by its conchoidal surface of fracture, by its high melting point, its gloss, its cloudy appearance and more especially by the remarkable property of not crystallizing from solutions but solidifying in the form of homogenous emulsions. In correspondence therewith the oxidation product of parafilne can be used similar to the higher melting parafilnes, such as ceresine or wax, in'the manufacture of technically or pharmaceutically and cosmetically active compounds, such as wax substitutes or compositions, creams, pastes,

greases, polishing pomades, impregnating masses, wax pencils and similar products. The percentage in the crude oxidation products and the esters recovered therefrom of free boric acid, which may be increased as desired by kneading with warm water, imparts to these products antiseptic properties, so that they can also be used for instance in the preparation of preserving ointments etc.

The oxidation products obtained according to this invention are fundamentally different as far as their properties are concerned from the products obtained in the manner hitherto practiced without the addition of boric acid and the like.

Obviously these new properties will become particularly apparent in the esters or the parafline alcohols, which have been freed from unconverted paraflines and fatty acids; these esters are particularly distinguished by their extremely high melting point, light color, high gloss and increased absorbing capacity for turpentine oil and form a particularly suitable starting material for the preparation of products such as above mentioned. In molten condition these esters are highly viscous.

The alcohol mixtures recovered from the crude and more especially from the refined esters by extracting the boric acid or other acids with boiling water or by other means are characterized by the property of forming when kneaded with water, glycerine or other similar liquids emulsions of an ointment-like consistency. They can be rubbed directly into the skin and have a hydrophile character. They may therefore be used in raw condition or after having been freed from parafiine by treatment with ethyl alcohol in a similar manner as wool fat in the production of emulsions, water-soluble oils, ointments, pastes, cosmetic creams, non-rancid. fats, as superfatting means for soaps and for similar purposes in the pharmaceutical and cosmetical practice as well as for all, technical purposes, either alone or mixed with protective colloids, waxes, hydrocarbons and the like.

More especially the alcohols freed from fatty acids and non-saponificable matter take up any quantity of glycerine and also up to and'beyond 100% water. In view of their capacity for dissolving iodine salicylic acid, camphor etc. they are quite suitable for the production of pharmaceutically efficient products.

The quantities and properties of the esters and the alcohols recovered from them according to this invention differ obviously according to the extent of oxidation and to the conditions under which oxidation has taken place. If the treatment with oxygen lasts too long and is carried out at an unduly high temperature the formation of fatty acids will increase to the detriment of the formation of alcohols, while conversely, if the period of oxidation is too short or the conditions too mild, a considerable percentage of the starting materials will not be attacked.

Example 1 Through a mixture of 100 parts of molten hard parafilne (melting point 54 C.), 6 parts boric acid and 3 parts sodium oxalate a vigorous ail current is conducted during 2 hours at a temperature of about 180200 C. The product of.

reaction which in molten condition has a viscous character is separated from the undissolved solution by filtration and on cooling solidifies forming an almost white, non-transparent mass with glossy surface and shelly, glossy fracture. Its further properties are the following:

Melting point 54,5 Acid number 24 Ester number 14 Saponification number 38 Ashes 1.. 3,1%

-boiled out with water until no boric acid can be traced in the water. The alcohol mixture thus obtained which is free from boric acid and light gray-yellow colored or almost colorless has the following characteristics.

Melting point 34 C Acid number l1 Ester number 27 Saponification number 38 Acetyl number 198 Ashes 0,01%

By saponiflcation, extraction of the soap solution with ether and evaporation of the ether, these crude alcohols can be freed from fatty acids and then show the following characteristics:

Specific gravity at 50 C 0.860 Melting point 31.5 C. Acid number 0.9 Ester number 6.5 Saponification number 7.4 Hyroxyl number 165 The crude and the refined alcohols can easily be rubbed into the skin and mixed with water and other liquids to form stable colorless emulsions.

Example 2 Through 100 parts of a mixture formed from equal parts of paraffine and soft wax recovered in the distillation of Montan wax, which melts at 57 0., to which have been added 2% sodium chloride and 4% boric acid anhydride, a vigorous air current is conducted during 3 hours at 170 C. The product of reaction is separated from the undissolved salt by filtration and solidifies to form a yellow mass melting at 56 C. and containing 2,6% ashes. The product is harder and more brittle than the starting maashes.

terial. If boiled out twice with water it shows the following characteristics:

The yield is 92% of the starting material.

From the oxidation product first obtained the boric acid esters can be .separated by treating it with hot alcohol, cooling the solution and separating the precipitate by filtration. After removal of the alcohol by distillation 22% boric acid ester are obtained which on being boiled out with water furnish a. product containing the alcohols and having the following characteristics:

Melting point 40 Acid number 20 Ester number Saponification number Hydroxyl number 140 Ashes 0.

When extracting the esters from the oxidation products instead of alcohol other similarly acting solvents may be used. Thus by using glacial acetic acid 33% of an extract is obtained, which after boiling out with Water shows the following characteristics Example 3 Parafifine is subjected at 170 C. in the presence of 4% arsenic trioxide during 4 hours to the intense action of a hot air current. The brownish product of reaction is filtered while still hot. The cold filtrate melts at 495 C. and contains 1.1% By treating this product with hot alcohols according to Examples 1 or 2 about 30% of the esters are obtained. By boiling out with water and dissolving in alcohol and subsequent filtration'about 20% calculated on the original parafiine of ash free crude alcohols having the hydroxyl number are recovered.

Example 4 It forms a yellow product melting at 49" C. and

containing 3.3% ashes. The yield Owing to the intense oxidation this product is altogether soluble in alcohol. It is treated at a temperature above normal with caustic soda solution, whereby the saponifiable acids including the boric acid was rinsed with petrol.

are dissolved. The insoluble part forming 62% of the total has the following characteristics:

Melting point 48 C. Acid number 0 Ester number 4 Saponification number 4 Hydroxyl number 130.

These crude alcohols can be freed from the unchanged parafiine by dissolving in hot alcohol and cooling, whereupon the parafiine will separate out, while the alcohols remain substantially in solution. On distilling off the solvent there is obtained a product melting at 405 C. and having the. hydroxyl number 184, the yield being 65% of the crude alcohol.

Example 5 An oxidation product of pale yellow color and melting at 53 C. which was obtained by treating paraffine melting at 52 C. under gradual addition of 5% boric acid anhydride with air at a temperature of 175-180 C. was heated on the steam bath under a reflux condenser with double the quantity of a low boiling petrol, boiling between 60 and 100 C., until everything was dissolved. The solution was left standing for some time and was then separated at a temperature of 10 C. from the product precipitated during the cooling down. In order to remove the solvent retained in the residue on the filter this residue The filtrate and residue were freed from petrol by distillation. There resulted 35 parts residue and 65 parts extract having the following characteristics:

Residue (esters) Flltrate C White Yellow From the residue further 7 parts extract were separated by further treatment with petrol. The boric acid ester thus considerably purified showed the following characteristics:

Color white Outer aspect highly glossy Melting point 73 C. Ashes 4,8%.

On being repeatedly boiled out with water there were obtained white ash free parafiine alcohols having the hydroxyl number 164, a melting point of 53 C. an acid number of 1,5 and a saponification number of 4,5.

Obviously this invention is not confined to the ways of proceeding described in the examples but comprises every oxidation of hydrocarbons,

waxes and similar matter as well as of mixtures of these substances with oxygen or oxygen containing gases, such as air, which is carried through in the presence of boric acid or boric acid anhydrides and/or the other acids to be substituted for boric acids. It further comprises the further treatment of the substances oxidized in the presence of boric acids or its analogues according to any of the methods described either per se or in any desired sequence and also ,to all products obtained according to the present invention.

Various changes may be made in the details disclosed in theforegoing specification without departing from the invention or sacrificing the advantages thereof.

modifications thereof and the right to subsequently make claim to any modification not covered by these claims is expressly reserved.

1. The method of oxidizing aliphatic hydrocarbonacomprising subjecting such hydrocarbons whilst in the liquid phase to the action of oxygen in the presence of a member of the group of acids consisting of boric acid, phosphorous acid and arsenious 'acid.

2. The method of oxidizing aliphatic hydrocarbons comprising subjecting such hydrocarbons whilst in the liquid phase to the action of oxygen in the presence of a member of the group of acid anhydrides consisting of boric acid anhydride, phosphorous acid anhydride and arsenious acid anhydride.

3. The method of oxidizing aliphatic hydrocarbons comprising subjecting such hydrocarbons whilst in the liquid phase to the action of oxygen in the presence of a mixture of boric acid and acetic acid.

4. The method of oxidizing aliphatic hydrocarbons comprising subjecting such hydrocarbons whilst in the liquid phase to the action 01 oxygen in the presence of phosphorous acid and acetic acid.

5. The method of oxidizing aliphatic hydrocarbons comprising subjecting such hydrocarbons whilst in the liquid phase to the action of oxygen in the presence of arsenious acid and acetic acid.

6. The method of oxidizing aliphatic hydrocarbons comprising subjecting such hydrocarbons whilst in the liquidphase to the action of oxygen in the presence of a member of the group of acids consisting of boric acid, phosphorous acid and arsenious acid, and extracting the products obtained with an aliphatic hydrocarbon to obtain pure esters.

'7. The method of oxidizing aliphatic hydrocarbons comprising subjecting such hydrocarbons whilst in the liquid phase to the action of oxygen in the presence of a member of the group of acids consisting of boric acid, phosphorous acid and arsenious acid, and freeing the products obtained from acid by boiling with Water.

8. The method of oxidizing aliphatic hydrocarbons comprising subjecting such hydrocarbons Whilst in the liquid phase to the action of oxygen in the presence of a member of the group of acids consisting of boric acid, phosphorous acid and arsenious acid, and freeing the products obtained from acid by saponification.

9. The method of oxidizing aliphatic hydrocarbons comprising subjecting such hydrocarbons whilst in the liquid phase to the action of oxygen in the presence of a member of the group of acids consisting of boric acid, phosphorous acid and arsenious acid, dissolving the products of oxidation and the esters of the said member of group of acids in a hot inert organic solvent to separate the Lee fatty acids formed by the said oxidizing treatment, cooling down the resulting solution,

and removing the boric, arsenious or phosphorous esters respectively thereby separated from the solution.

10. The method of oxidizing aliphatic hydrocarbons comprising subjecting such hydrocarbons whilst in the liquid phase to the action of oxygen in the presence of a member of the group of acids consisting of boric acid, phosphorous acid and arsenious acid, and extracting the products obtained with an inert organic solvent to eliminate the non-oxidized hydrocarbons and fatty acids from the resulting esters of boric, phosphorous or arsenious esters respectively.

11. The method of oxidizing aliphatic hydrocarbons comprising subjecting such hydrocarbons whilst in the liquid phase to the action of oxygen in the presence of a member of the group of acids consisting of boric acid, prosphorus acid and arsenious acid, and treating the products of oxidation with an inert organic solvent to separate the resulting esters of boric, phosphorus or arsenious acid respectively from the non-oxidized hydrocarbons. I

12. The method of oxidizing aliphatic hydrocarbons comprising subjecting such hydrocarbons whilst in the liquid phase to the action of oxygen in the presence of a member of the group of acids consisting of boric acid, phosphorus acid and arsenious acid, dissolving the products of oxidation and the resulting esters of boric, phosphorous or arsenious acid respectively with an aliphatic hydrocarbon and recovering the esters from their solution.

13.,The method of oxidizing aliphatic hydrocarbons which comprises subjecting such hydrocarbons whilst in the liquid phase to the action of oxygen in the presence of a member of the group of acids consisting of boric acid, phosphorous acid and arsenious acid, and of a watersoluble alkali metal salt.

14. The method of oxidizing aliphatic hydrocarbons which comprises subjecting such hydrocarbons whilst in the liquid phase to the action of oxygen in the presence of a member of the group of acids consisting. of boric acid, phosphorous acid and arsenious acid, and of a watersoluble alkali metal salt selected from the group consisting of oxalates and chlorides.

15. The method of oxidizing aliphatic hydrocarbons which comprises subjecting such hydrocarbons whilst in the liquid phase to the action of oxygen in the presence of a member of the group of acids consisting of boric acid, phosphorous acid and arsenious acid, and of a watersoluble sodium salt.

16. The method of oxidizing aliphatic hydrocarbons which comprises subjecting such hydrocarbons whilst in the liquid phase to the action of oxygen in the presence of a member of the group of acidsconsisting of boric acid, phosphorous acid and arsenious acid, and of a watersoluble sodium salt selected from the group consisting of sodium oxalate and sodium chloride.

THEODOR HELLTHALER. ERICH PETER.