US2144260A - Method of preparing an emulsifiable oil - Google Patents

Description

Patented m 17, 1939 T ES PATENT oFFlcE [2,144,260 METHOD or rnn'raigg o AN EMULSIFIABLE William H. Hampton and Norman N. Gay, Berk-- eley, Caliil, assignors to Standard Oil Company. of California, San Francisco, Calif., a corporation of Delaware No Drawing. Application July 15, 1936, Serial No. 90,756

5 tilaims.

This invention relates to a new and improved soluble oil and to a process of preparing the same. Although the soluble oil-prepared accord- .ing to the present invention is particularly useful as an insecticide it is also applicable for use as a cutting oil and for other purposes.

The term soluble oil as used herein is intended to designate an 011 containing an internal emulsifier which renders the oil readily dispersible in water. Such dispersions of oil in water are, of course, not true solutions. The term soluble oil is nevertheless commonly used in the trade to designate oils which are readily dispersible or emulsifiable in water with or without vigorous agitation and without incorporation of additional emulsifying agents in the water or oil at the time of emulsification. The term is so used in the present specification.

Numerous soluble oils have in the past been prepared, for various purposes among which is their use for insect control. Such oils have contained many different types of emulsifying agents among which have been petroleum sulfonates.

In the past when petroleum sulfonates' have been utilized to produce emulsification, it has been found necessary either to use sulfonates in amounts of more than 10% by weight based on the amount of oil or to use auxiliary agents in addition to thesulfonates in order to aid emulsi ,fication and to obtain an oil composition readily dispersible in water to give satisfactory emulsions. Usually as much as 20 to 40% of sulfonates" by weight based on the amount of the oil has been it emulsiflable. Preparation and isolation of these sulfonates involve expensive extraction and purification steps. Despitev this fact such purification processes have apparently been regarded as necessary and essential to the production of'satisfactory insecticidal soluble oils. v

We have discovered not only that these purification processes are'not necessary but that they are actually undesirable because heating and drying in air cause deterioration of the sulfonate compounds. The method of this invention yields more effective and desirable compounds with less trouble and expense. I v

The present invention enables one to produce a satisfactory soluble oil without the addition of such large amounts of petroleum sulfonates as will render a phytonomic oil distinctlyphytocidal'.

This invention also provides a process which avoids the expensive steps of separating-the sulfonates from oil, and purifying them by the various well known washing treatments. The invention also avoids the deterioration of the sulfonate compounds incident to heating and drying the separated compounds in air.

Accordingly, it is an object of this invention to provide a soluble oil containing less than 10% petroleum sulfonates but capable of forming satisfactory oil in water emulsions.

It is also an object of this invention to provide a process of producing soluble phytonomic oils utilizing petroleum sulfonates as an internal emulsifier which process omits sulfonate extraction and purification steps heretofore regarded as essential or necessary.

A further object of the invention is to provide a phytonomic insecticidal oil by retaining in the oil reaction products (presumably petroleum sulfonates) formed in situ by reaction of sulfuric acid on the oil and subsequent neutralization of the reaction products with an alkali.

An additional object of the invention is to form a soluble oil by first extracting a substantial proportion of the sulfonatable hydrocarbons froma mineral oil and then'treating the extracted mineral oil with sulfuric 'acid to form reaction products in situ, which, when neutralized with an alkali and retained in the oil, have the general characteristics of petroleum sulfonates but which are capable of emulsifying-the oil in water even when. present in proportions of only 2 to 10% by weight based on the oil.

Another object of the invention is to provide a method of preparing a soluble oil which avoids deterioration and discoloration of the petroleum 'sulfonates by exposure of the separated compounds to heat and air.

Attention is directed to the fact that phytenomic oils are relatively free from unsaturated; aromatic and other more. reactive or easily sul-afonatable compounds. These types of compounds normally present in mineral oils are the constituents which are generally accepted as responsible for the phytocidal action of the mineral oils.

these phytocidal constituents and to render the oil phytonomic and suitable for. application to verdant vegetation as an insecticide. Phytonomic oils made according to the above processes have in general an unsulfonatable residue of approximately 85% or more. 7

Although it is well known that petroleum sulfonates suitable for making soluble mineral oils when added in proportions of 20% or more are obtainable from unrefined oils, it does not follow that the same materials are obtainable from selective solvent extracted oils which contain relatively small amounts, if any, of the highly reactive or easily sulfonatable compounds normally present in a phytocidal oil. Likewise it is believed to be unpredictable that such reaction products formed in situ in a mineral oil would prove more satisfactory as an internal emulsifier for insecticidal oils than petroleum sulfonates obtained from the more reactive mineral oil fraction and by the usual separation involving alcoholic washes and other purification steps. products are formed by the action of sulfuric acid on mineral oils and it might well be expected that sufficient of such undesirable reaction products would be retained in the oil'to reduce or interfere with the emulsifying action of the sulfonate compounds. Also it might be expected that undesirable constituents would be retained in the oil in quantities sufficient to render it phytocidal. Whether the above suggestions or other reasons are responsible for the practice in the art cannot be definitely stated, but in any event commercial producers in general have regarded extraction and purification of petroleum sulfonates as essential to the production of satisfactory insecticidal oils using these compounds as emulsifiers.

We have discovered that a mineral oil may be treated to produce reaction products in situ which are highly efiicient in amounts as low as 2% in producing emulsification of the oil. This treatment comprises broadly, reaction I of a solvent extracted mineral oil with sulfuric acid and neutralization of the reaction products while in solution in the oil with an alkali such as potassium hydroxide, potassium carbonate and similar alkaline materials. The neutralized reaction products useful for our purposes are soluble in the oil and retained therein. The potassium salts of the sulfuric acid reaction products are more efficient than sodium salts in producing emulsification of the oil. However, the use of sodium hydroxide and its equivalents as a neutralizing agent is to be regarded as falling within the broader scope of the invention.

By analogy to the reaction of sulfuric acid with unrefined petroleum oils to form sulfonic acids, it is believed that the reaction products formed by our process may likewise be termed sulfonic acids,

and after neutralization may be designated petroleum sulfonates. It should be understood, however, that the scope of the invention or validity of the claims is not to depend on a scientifically correct chemical designation of the compounds formed. The phrases petroleum sulfonates, sulfonic acids or reaction products having the characteristics of sulfonic acids are, used merely as the most convenient and descriptive designation for the reaction products of the present invention.

In carrying out the process of our invention it is preferred to treat an oil having aviscosity of from 'to 100 seconds Saybolt at 100 F. The hydrocarbons of such a suitable oil have an average molecular weight in the range 'of 200 to 400. This preferred oil yields reaction products more efficient in producing emulsification than do heavier or lighter mineral oil fractions. This Polymerization able residue of approximately "slble, however, to extract the oil with selective Particular fraction of oil is also the most desirable for use as an insecticide.

It is also preferred to treat these oils so that more than 2% and less than 4% of potassium or sodium sulfonates are retained therein as an internal emulsifier. Although such a procedure is preferred, we are not precluded from retaining in the oil smaller amounts such as 0.4 to 2% sulfonates and enhancing the emulsifying power of these smaller quantitiesby known means such as surface tension modifiers of the type of acetone and other low molecular weight ketones, alcohols,

aldehydes, esters, amines, ethers and amides which are soluble in both oil and water. We make no claim to the addition of these materials per se as our invention but regard their combination with the novel features herein'disclosed' as within the broad scope of this invention.

Also we are not precluded from using an emulsifiable oil containing as much as 10% of petroleum sulfonates produced according to this invention. Where the spray oil is to be applied to plants during the winter months as a dormant spray as much as 10% petroleum sulfonates may be utilized without harm to the vegetation. Likewise certain plants are more resistant to these materials and sufler no ill effects from amounts of sulfonates somewhat greater than 4%.

It is also feasible to produce a spray oil composition according to our invention containing as much as 10% petroleum sulfonates and todilute this product with sufiicient phytonomic oil substantially free from sulfonates or other emulsifying agents and thereby reduce the proportion of sulfonates to, for example, 2 /2% based on the weight of the oil. Such an alternative obviously is advantageous in converting a dormant spray into one suitable for use during the summer months or for application to more sensitive plants. I

To illustrate the process and product of the invention the following specific example is given:

A California distillate is first extracted with any known suitable selective solvent, liquid sulfur dioxide for example, to remove the more highly reactive and easily sulfonatable compounds. Such California distillates usually have an unsulfonatable residue of from 50 to 60% prior to the extraction. In practicing the present invention the distillate is preferably extracted to give a partially refined rafflnate having an unsulfonat- It is possolvents to produce a phytonomic oil or more unsulfonatable residue) and by more drastic sulfuric acid treatment produce sufiicient quantities of sulfonic acids for the purposes of the present invention. The sulfur dioxide treated distillate used in this particular example had a viscosity of 92 to 97 at 100 F. and an unsulfonatable residue of 80-82%. Nine gallons of this treated distillate is placed in a lead lined agitator at a temperature not to exceed F. Four and one-half pounds of 15 fuming sulfuric acid are added with constant air agitation and agitation is continued for 15 minutes after all the acid is in. Ninety eight percent sulfuric acid could be used, but a greater amount than that represented bythe difference in acid strength would be required in order to obtain comparable treatment. The sludge is separated after 9 to 12 hours standing and two additional 4 pound dumps of 15 fuming acid are added followed by 6 to 8 hours settling each time before withdrawing the lower Kill) pounds per gallon of charge or 0.5 pound per gallon per dump in three dumps. Where the spray oil is to have an unsulfonated residue of approximately 87% as is preferred (when the sulfonates are washed out with alcohol the same oil would have an unsulfonated residue of approximately 90%), somewhat more or less acid may be required depending upon the particular stock being treated.

Sufficient caustic potash or caustic soda of 48 to 50 Baum strength is then added to exactly neutralize the batch. The batch is blown with air during the addition of caustic and for one hour after adding the caustic. 'The batch is then air blown at 140 F. for one hour or until the water content is .1% or less. In general, 70 to 80 cc. of 48 Baum caustic soda will be suflicient to neutralize each gallon of charge or .02 gallon of 40 Baum caustic soda per gallon of oil charged. One hundred to 110 cc. of 48 Baum caustic potash will be required to neutralize each gallon of charge or 026 to .029 gallon of 48- Baum caustic potash per gallon of oil charged.

The major part of the inorganic salts will separate on 24 hours standing. Where a bright emulsifiable oil is required, centrifuging may be desirable.

Strong caustic or potash, as distinguished from the 20 Baum caustic soda ordinarily used in such a neutralization process, is utilized in order to cut down on the amount of water added and thus prevent a separation of the sulfonates to the aqueous layer. This concentrated solution of alkali also shortens the time required for air blowing in order to produce a-product with a good color.

An'oil prepared by the above process using 481 Baum KOH as the neutralizing agent has the following characteristics:

Gravity (A. P. I.) 26.4 Flash point; 320 F. Fire point 365 F. Viscosity at 100 F 98 Unsulfonated residue 87 Percent sulfonates 2.5

Percent water Trace This oil readily emulsified with water in the proportions of 2 parts of oil to 98 parts of water and remained emulsified for two hours.

The color of the finished product was superior to that obtained when sulfonates are added to the oil, due to the fact that sulfonates as ordinarily produced are heated to 210- to 240 F. to remove water and the heating darkens the sulfonates considerably. The process of this invention avoids the deterioration resulting from heat.

give a partially refined oil having an unsulfonatable residue of at least approximately treating said refined oil with sulfuric acid to form reactionproducts therein having the characteristics of sulfonic acids, neutralizing said reaction products with an alkali, and maintaining in solution in the oil a substantial portion of said neutralized reaction products as an emulsifying agent for the completed oil, said retained portion comprising from approximately 0.4% to approximately 10% by weight of said oil.

2. A process of producing a soluble phytonomic insecticidal oil comprising treating a mineral oil with sulfuric acid to form a solution in the oil of reaction products having characteristics of sulfonic acids, separating sludge formed by said acid treatment from said oil solution, neutralizing said oil solution of reaction products with an alkali, and maintaining in solution in the oil without removal therefrom a substantial portion of said neutralized reaction products as an emulsifying agent for the completed insecticidal oil, said retained portion of neutralized reaction products comprising from approximately 0.4% to approximately 10.0% by weight of said oil.

3. A process of producing an insecticidal oil comprising treating a refined petroleum oil having an average molecular weight in the range of 200 to 400 and an unsulfonatable residue of 80% or more, with concentrated sulfuric acid to form an oil solution of reaction products having characteristics of sulfonic acids, neutralizing said reaction products with an aqueous solution of an alkali, and maintaining in solution in the oil a portion of said neutralized reaction products as an emulsifying agent for the completed soluble oil, said retained portion comprising from approximately 0.4% to approximately 10% by weight of said cbmpleted oil.

4. A process of producing an insecticidal oil comprising treating a phytonomic petroleum oil having a molecular weight in the range of 200 to 400, a viscosity offrom 50 to 100 seconds Saybolt at 100 F. and an unsulfonatable residue of at least approximately 80%, with concentrated sulfuric acid to form an oil solution of reaction products comprising sulfonic acids, neutralizing said reaction products with an alkali, and maintaining in solution in the oil a portion of said neutralized reaction products as an emulsifying agent for-the completed insecticidal oil, said retained portion comprising from approximately 2 to approximately 4% by weight of said insecticidal oil.

5. A process of producing a soluble oil comprising treating a mineral oil having an unsulfonatable residue of from approximately 80 to with sulfuric acid to form an oil solution of reaction products having characteristics of sulfonic acids, 'se'paratingsludge formed by said acid treatment'from said oil solution, neutralizing said reaction products with an alkali, and maintaining in solution in the oil from 0.4 to 10% by weight of said neutralized reaction products as an emulsifying agent for the completed soluble oil.

- H. HAMPTON.

-NORMAN N. GAY.