US2344154A - Sulphonation process - Google Patents

Description

Patented Mar. 14, 1944 SULPHONATION PRGCESS Charles H. Lighthipe, Bloomfield, N. J assignor to National Oil Products Company, Harrison, N. .L, a corporation of New Jersey N o Drawing. Application December 23, 1941, Serial No. 424,142

11 Claims.

This invention relates to a novel process for preparing sulphonated oils, fats and waxes and in particular to a process for producing such materials of high S03 having a substantial free fatty acid content.

For certain purposes it is desirable to use sulphonated oils, fats r waxes having a high content of free fatty acids, as well as a high S03 content, notably in certain textile, leather and paper treating or manufacturing processes where the oils must be used in acid media without loss of wetting power.

sulphonated oils are generally prepared by a process which involves (1) the step of sulpho- Rating wherein the raw oil or like fatty ma- {Qrial is reacted with sulphuric acid to form a swphonation mass; (2) the step of washing herein the sulphonation mass is dropped into 3 quantity of wash water wherein most of the unspent acid is washed out of the mass; and (3) {he step of panning wherein the washed oil permitted to stand for the purpose of allowmg excess water to separate out, i. e. until most t fthe water entrained therein separates out. The unspent acid remaining in the oil after the washing step and also the acid sulphate radicles combined with the oil are generally neutralized before or at the commencement of the panning step. customarily, in order to develop large quantities of free fatty acids in sulphonated oils produced as above set forth, the oil is left for some time in contact with the acid Water in the washing step, or the water in the panning step is allowed to become acid, the acid in each case acting as a catalyst to hydrolyze the oil and to produce the desired amount of fatty acids. However, during this process of hydrolysis, not only is the oil hydrolyzed to form. free fatty acids and degraded glycerides, but also a certain amount of the combined S03 is split off from the oil. This splittingis undesirable in several respects: first, in that it necessitates prolonged sulphonation, of the oils in order to attain any given degree of sulphonation in the final product; second, in that it is impossible to produce a sulphonated oil having both a high acid value and a high S03 contentfor instance, heretofore when sulphonated castor oil has been produced with an acid value in excess of lOO. it has been impossible to obtain an S03 content in excess of 5% or 6%--; and finally, in that the splitting off Of'the combined S03 results in hydroxylation of the oil, which tends to make the. oil cloudy, and in many cases, solid at ordinary temperatures Accordingly, it is anobject of this invention to produce sulphonated oils of high free fatty acid content without subjecting the oils to prolonged contact with acid liquors with consequent sacrifice in S03 content. It is a further object to provide a process for obtaining both a high free fatty acid and a high percentage of combined S03 in a sulphonated oil.

It is a further object of this invention to provide a process which can be carried out with greater expedition than the prior processes.

It is a still further object to shorten the time of sulphonation required in order to produce a high free fatty acid sulphonated oil of any given S03 content.

The above and other objects are. achieved'by this invention in aprocess which involvesfirst sulphonating the oil'by means of sulphuric acid or other suitable sulphonating agent; thendropping the sulphonated oil into a body ofwash water, preferably containing at least enough alkali to neutralize the excess sulphonating agent; thereafter, if necessary, adding further alkali to saponify the oil and produce an amount of soaps of the sulphonated fatty acids equivalent to the free fatty acid content desired in the final product; and finally adding sufiicient mineral acid to the mass to decompose the soaps and produce the desired free fatty acid content.

The process of this invention is applicable to the various fatty ester bodies usually subjected to sulphonation processes such as the unsaturated and/or hydroxylated oils, fats and waxes. Examples of suitable unsaturated oils include, inter alia, olive oil, teaseed oil, peanut oil, rice bran QiL'menhaden oil, cod oil and the like. Suitable hydroxylated bodies include, among others, castor oil or oils which have been Wetblown to develop hydroxyl groups therein, such as wet-blown coconut oil. An example of an unsaturated wax suitable for use in this invention is sperm oil.

The sulphonation step may be carried out in any usual and suitable manner. Commonly, this will involve treating the oil with sulfuric acid at moderately low temperatures. However, I

desired, other known sulphonation procedures and reagents, such as treatment with oleum, chlorsulphonic acid and the like, may be employed.

In the above process the body of water into which ,the oil from the sulphonation step .is dropped preferably contains sufficient alkali to both neutralize the unspent sulphonating agent additional alkali being added subsequently. Likewise, the alkali may be added to the sulphonated mass before it i dropped into the body of water. In any event the total amount of alkali required may be readily calculated from the analysis of the oil just before it is dropped into the bath.

Thus if the mass contains excess acidity, calculated as sulphuric acid, due both to the unspent sulphuric acid and the acid sulphate radicles combined with the oil:

must be added to just neutralize the unspentsulphonating agent. If it is desired to develop free fatty acids, assuming a molecular weight for the triglycerides of 900:

- NaOH 40 must be added over and above that required for the neutralization of the unspent sulphonating agent. NaOH was cited above as being a suitable alkaline agent for neutralizing and saponifying the oil; however, any other suitable alkali such as KOI-I may be used.

It will be seen that in the process of the present invention the oil is never in contact for any extended time with acid aqueous solutions; and as a result, no splitting off of the sulphate groups in the oil will occur as it will in the conventional process. This has two advantages: first, that a sulphonated oil of higher S03 content may be obtained, and second, that sulphonation need not be prolonged in order to provide an excess of combined S0: to be split off during the conventional acid washing process. i

Oils sulphonted in accordance with the procedure above set forth are distinguished from other oils heretofore made in that they possess a high content of both combined S03 and free fatty acids. Further, they are distinguished from earlier oils in that they are relatively more fluid at room temperature, which is believed to be due to the fact that in the acid panning processes of the prior art, the sulphate groups are split off from 'the fatty radicals, leaving hydroxyl groups in their place, which hydroxyl groups tend to the formation of solid products rather than liquid products. tage is of lesser importance in the case of oils which were already hydroxylated before the sul phonation step, inasmuch as no additional hydroxy groups are introduced by the usual process. However, the advantage of securing both high free fatty and high S03 contents remains.

Following are examples illustrative of the process according to this invention and also, for comparison, of processes according to the prior art. All parts given are by weight.

Example I ing sulphonation mass was dividedinto two parts, one part being reserved fortreatment in accordance with Example II below.

It will be noted that this last advan- I To 100 parts of the sulphonated mass produced as just described were added 92 parts of 24% aqueous caustic soda and the mass left to stand until a test for free alkali was negative. Thereafter sufficient sulphuric acid was added to the mass to reduce the total alkali to .2% and the entire mass was dropped into 200 parts of Water, agitated therewith and panned, i. e. allowed to settle overnight at C. A sulphonated oil layer collected on the top and the salt water on the bottom was drawn off. Sufiicient caustic soda (2% based on the weight of the oil) was added to clarify the oil. The resultant oil contained 25% moisture, had a free fatty acid content of 30% (including the fatty residues combined with the alkali as soap) and a combined $03 of 10%, and was a clear, reddish amber liquid oil.

Example II To be distinguished from. the present invention 100 parts of the reserved portion of the sulphonated mass prepared as above described in Example I were poured into 200 parts of water and sufficient soda added thereto to reduce the acidity to .5% (calculated as H2804 and based on the weight of the entire mass). The mass was kept in agitation until the free fatty acid content stopped increasing. Thereafter the mass was panned overnight at 50 C. and a layer of sulphonated oil separated out on top of the mass. The salt water layer was drawn off and sufiicient caustic soda (2%) based on the weight of the oil was added to the oil to clarify the same. The resultant product contained 25% moisture, had a free fatty acid content of 20% (including the fatty residues combined with the alkali as soap) and a combined S0 content of 8%, and changed to a tan-colored solid upon cooling.

Example III 100 parts of peanut oil were chilled to 15 C. and 24 parts of concentrated sulphuric acid were added thereto With stirring and with chilling to keep the temperature below 20 C. The stirring was continued for 2 hours, after which the resulting sulphonated mass was divided into two parts, one part being reserved for treatment in accordance with Example IV below.

To 100 parts of the sulphonated mass produced as just described were added parts of aqueous 24% caustic soda and the mass left to stand until a test for free alkali was negative. Thereafter sufiicient sulphuric acid was added to the mass to reduce the total alkali to .2% and the entire mass was dropped into 200 parts of water, agitated therewith and panned at 50 C. overnight. The sulphonated oil layer collected on the top and the salt water layer on the bottom was drawn off. Sufficient alkali (2% based on the weight of the oil) was added to clarify the oil. The resultant oil contained 30% moisture, had a free fatty acid content of 58% (including the fatty residues combined with the alkali as soap) and a combined S03 of 10% and was a liquid oil which clouded slightly on cooling to room temperature.

Ewample IV a To be distinguished from the present invention parts of the reserved portion of the sulphonated mass prepared as above described in Example III were poured into 200 parts of water and sufficient soda added thereto to reduce the acidity to .5% (calculated as H2504 and based on the weight of the entire mass). ihe mass was kept in agitation until the free fatty. acid con- Example V 100 parts of castor oil were chilled to C.

and 24 parts of concentrated sulphuric acid were added thereto with stirring and with chilling to keep the temperature below C. The stirring was continued for 5 hours, after which the resulting sulphonated mass was divided into two parts, one part being reserved for treatment in accordance with Example VI below;

To 109 parts of the sulphonated mass produced as just described were added 51 parts of aqueous 24% caustic soda and the mass left to stand until a test for free alkali was negative. Thereafter sufficient sulphuric acid was added to the mass to reduce the total alkali to .2% and the entire mass was dropped into 209 parts of water, agitated therewith and panned at 50 C. overnight.

A sulphonated oil layer collected on the top and the salt water layer on the bottom was drawn off. Sufiicient alkali (2% based on the weight of the oil) was added to clarify the oil. The resultant oil contained 25% moisture, had a free fatty acid content of 42% and a combined S03 of 5% and was a clear, light-amber liquid oil.

Example VI To be distinguished from the present invention 100 parts of the reserved portion of the sulphonated mass prepared as described above in Example I were poured into 200 parts of water and sufficient soda added thereto to reduce the acidity to .5% (calculated as H2804 and based on the weight of the entire mass). The mass was kept in agitation until the free fatty acid content no longer increased. Thereafter the mass was panned overnight at C. and a layer of sulphonated oil separated out on top of the mass. The salt water was drawn off and suflicient alkali (6%) based on the weight of the oil was added to the oil to clarify the same. The resultant product contained 22% moisture, had a free fatty acid content of 42% and a combined S03 content of 2% and was a dark-colored, clear and fluid oil.

From the above examples it will be seen that in every case where the procedure of the present invention was followed with a given oil, the S03 content was not diminished from that obtained just at the finish of the sulphonation process, while in the case of the same oils processed according to prior procedures, the S03 content was diminished to a large extent. As above pointed out in the general discussion of this invention. this degradation is undesirable in that it is necessary to carry out a more drastic sulphonation in order to secure a product with any given S03 content. Further, the products according to the present invention, not having been subjected to splitting off of the combined S03, are not hydroxylated and are accordingly more fluid and clear than similar products heretofore manufactured. While the expressions sulphonation and sulphonated have been used in this application in accordance with their prior usage 111 the art as commercially practiced, the process of the invention technically involves sulphation, i. e. formation of a sulphuric acid ester with the fatty molecules rather than the sulphonic acid derivatives.

Having described my invention what I claim as new and desire to secure by Letters Patent is:

1. Process of making a sulphonated material of high S03 having a substantial free fatty acid content from an ester type fatty body susceptible of sulphonation selected from the group consisting of oils, fats and waxes, which comprises subjecting such a body to a sulphonating agent to cause the same to combine with the desired amount of S03; saponifying the body to a sufficient degree to produce therein an amount of fatty soaps equivalent to the amount of free fatty acids it is desired to develop in the final body; and splitting said soaps to form the corresponding free acids in the sulphonated mass.

2. Process of making a sulphonated material of high S03 having a substantial free fatty acid content from an unsaturated fatty oil, which com-- prises subjecting said oil to a sulphonating agent to cause the .oil to combine with the desired amount of S03; saponifying the oil to a sufficient degree to produce therein an amount of fatty soaps equivalent to the amount of free fatty acids it is desired to develop in the oil; and splitting said soaps to form the corresponding free acids in the sulphonated oil.

3. Process of making a sulphonated material of high S03 having a substantial free fatty acid content from a fatty oil containing at least one hydroxyl group, which comprises subjecting said body to a sulphonating agent to cause the oil to combine with the desired amount of S03; saponifying the oil a sufficient degree to produce therein an amount of fatty soaps equivalent to the amount of free fatty acids it is desired to develop in the oil; and splitting said soaps to form the corresponding free acids in the sulphonated mass.

4. Process of making a sulphonated material of high s03 having a substantial free fatty acid content from castor oil, which comprises subjecting said castor oil to a sulphonating agent to cause the oil to combine with the desired amount of S03; saponifying the oil a sufficient degree to produce therein an amount of fatty soaps equivalent to the amount of free fatty acids it is desired to develop in the oil; and splitting said soaps to form the corresponding free acids in the sulphonated oil.

5. Process of making a sulphonated material of high S03. having a substantial free fatty acid content from sperm oil, which comprises subjecting said oil to a sulpho-nating agent to cause the oil to combine with the desired amount of S03; saponifying the oil to a suflicient degree to produce therein an amount of fatty soaps equivalent to the amount of free fatty acids it is desired to develop in the oil; and splitting said soaps to form the corresponding free acids in the sulphated oil.

6. Process of making a sulphonated material of high S03 having a substantial free fatty acid content from peanut oil, which comprises subjecting said oil to a sulphonating agent to cause the oil to combine with the desired amount of S03; saponifying the oil to a sufficient-degree to produce therein an amount of fatty soaps equivalent to the amount of free fatty acids it is desired to develop in the oil; and splitting said soaps to form the corresponding free acids in the sulphonated oil.

7. Process of making a sulphonated material of high S03 having a substantial free fatty acid content from an ester type fatty body susceptible of sulphonation selected from the group consisting of oils, fats and waxes, which comprises treating such a body with sulphuric acid to cause the same to combine with the desired amount of S03; saponifying the body to a sufficient degree to produce therein an amount of fatty soaps equivalent to the amount of free fatty acids it is desired to develop in the final body; and splitting said soaps to form the corresponding free acids in the sulphonated mass.

8. Process of making a sulphonated material of high S03 having a substantial free fatty acid content from an ester type fatty body susceptible of sulphonation selected from the group consisting of oils, fats and waxes, which comprises subjecting such a body to a sulphonating agent to cause the same to combine with the desired amount of S03; saponifying the body to a sufficient degree to produce therein an amount of fatty soaps equivalent to the amount of free fatty acids it is desired to develop in the final body; splitting said soaps to form the corresponding free acids in the sulphonated mass; and panning said body in mildly alkaline solution to reduce the moisture content thereof.

9. Process of making a sulphonated material of high S03 having a substantial free fatty acid content from an unsaturated fatty oil, which comprises subjecting said oil to a sulphonating agent to cause the oil to combine with the desired amount of S03; saponifying the oil to a sufficient degree to produce therein an amount of fatty soaps equivalent to the amount of free fatty acids it is desired to develop in the oil; splitting said soaps to form the correspondin free acids in the sulphonated oil; and panning said body in mildly alkaline solution to reduce the moisture content thereof.

10. Process of making a sulphonated material of high S03 having a substantial free fatty acid content from a fatty oil containing at least one hydroxyl group, which comprises subjecting said body to a sulphonating agent to cause the oil to combine with the desired amount of S03; saponifying the oil to a suflicient degree to produce therein an amount of fatty soaps equivalent to the amount of free fatty acids it is desired to develop in the oil; splitting said soaps to form the corresponding free acids in the sulphonated mass; and panning said oil in mildly alkaline solution to reduce the moisture content thereof.

11. Process of making a sulphonated material of high S03 having a substantial free fatty acid content from an ester-type fatty body susceptible of sulphonation selected from the group consisting of oils, fats and waxes, which comprises subjecting such a body to a sulphonating agent to cause the same to combine with the desired amount of S03; saponifying the body by treating it with a sufficient quantity of caustic alkali to produce therein an amount of fatty soaps equivalent to the amount of free fatty acids it is desired to develop in the final body; and splitting said soaps to form the corresponding free acids in the sulphonated mass.

CHARLES H. LIGHTI-HPE.

CERTIFICATE OF CORRECTION. Patent No. 2,5L l ,15L March 11;, 19%.

CHARLES H. LIGHTHIPE.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 5, ,second column, line 56, claim 5, and page 11., second column, line 11, claim 10, for "body" read oil--; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office.

si ned and sealed this 16th day'of may, A. D. 19%

Leslie Frazer (Seal) Acting Commissioner of Patents.