US1963918A - Pour point depressor - Google Patents

Description

June 19, 1934. F. H. MacLAREN POUR POINT DEPRESSOR Filed June 29, 1933 Depreor OOQTex) Chlor-Wax om einer 4 7 f JtLlghPouPoinf OL LOM/pourpomt OL'L Patented June 19, 1934 room rorN'r nsrnnssoa Frederick H. MacLaren, Calumet City, Ill., al-

signor to Standard Oil Company, Chicago, Ill., a corporation of Indiana Application June Aze, 193,3, serial No. crasse i e claims. (c1. s'z-s) This invention relates to pour test depressors and it pertains more particularly to the preparation and use of an improved synthetic product which may be used for improving the viscosity indices of lubricating oils and which may be added to lubricating oils, transformer oils, fuel iols, etc. for the purpose of lowering their cold sts.

'I'he object of my invention is to provide an improved pour test depressor which will not only be eective on light oils and under conditions of slow chilling, but which will also be eiIective in highly viscous oils, such as bright stocks and S. A. E. 40 and 50 lubricating oils, whether the oils are slowly chilled or shock chilled. A further object is to provide a pour test depressor which can be used in such small quantities that it will impart no objectionable color or carbon residue to a lubricating oil. A further object is to improve the method of making pour test depressors of this type and to obtain larger yields of more potent products. Other objects will be apparent from the following detailed description.

In practicing my invention I react a halogenated hydrocarbon, such as chlorinated wax, with an aromatic compound, such as naphthalene, at temperatures of about 25o-350 F. by adding thereto small amounts of aluminum chloride. In my copending application No. 652,285, filed January 18, 1933, I described a reaction temperature of about 14o-160 F. (although I did not limit myself to such temperatures); since filing said application I have discovered that improved results may be obtained by employing a reaction temperature which is not only higher than that used in my early work, but higher than that shown in any of the prior art, my improved range being about Z50-350 F. I have discovered that the reaction which takes place under these conditions is strongly endothermic, which is quite different than the usual Friedel-Craft synthesis. I have found that by using this high temperature range much less aluminum chloride is required than is required at temperatures under 200 F., that the high temperature products have much better colors than have ever before been obtained, and that the high temperature products are more reactive than any pour test depressors heretofore known. Also, the high temperature products are much more easily separated from the aluminum chloride sludge,'the use of diluentsor solvents may be completelyeliminated, and the character of the aluminum sludge may be controlled by regulating the amount of aluminum chloride used at different temperatures.

The accompanying drawing which forms a part of this specification is a diagrammatic flow, representing an elevational plan of my improved apparatus.

As a specic example of my invention I will de- CL scribe the preparation and use of a specific depressor: 180 parts by weight of chlorinated wax (130 F. melting point parain wax chlorinated to 13.75% chlorine) are heated with 20 parts by weight of naphthalene to a temperature of 300 F.; two parts by weight of aluminum chloride are gradually introduced into this mixture, the addition requiring about one to two minutes, and it should be understood, of course, that the relative proportions of chlorinated wax and naphthalene 7s may be varied somewhat from this preferred formula. The mixture is stirred and maintained at this temperature for a period of about two to twenty minutes, preferably about ten minutes. The hot products are then separated from the. granular sludge by filtration and/or by gravity, and the reaction products are neutralizedwith hot caustic soda to completely remove all uncombined and loosely bound chlorine, hydrochloric acid, etc. This hydrolysis, or addition of sodium hydroxide, is preferably carried out with a hot concentrated caustic solution at a temperature of about 200 F., but I may employ dry sodium hydroxide at temperatures of from 250400 F. The neutralized products are then washed with water and are ready for use. The resulting product is a pour point depressor which is designated by the trade-mark Pourex. This Pourex is solid at room temperature, being about the consistency of crude petrolatum base. Its viscosity at 210 F. is about 238, its true color is about 1200, and its chlorine content is about two to three percent.

If desired, I may concentrate this product by vacuum distillation to remove certain waxy components and to leave a more potent residue. -Such a distillation may be made at temperatures of from 500 to 700 F. under an absolute pressure of about 4 mm. to 10 mm. of mercury. Some chlorine compounds are removed by the distillation, but a large percentage of the chlorine remains stably bound as a constituent of the chemical compounds Which make up the pour point depressor. Usually high temperature vacuum distillation is unnecessary, since excellent results are obtained without it.

As above stated, my preferred temperature range is 25o-350 F. I may employ temperatures as high as 400 F. but I have found that if the temperature is maintained at a higher level than 400, there is a violent reaction and that no pour test depressors are produced. Lower temperatures, such as 13o-200 F., require much longer periods of time, and excessively large amounts of aluminum chloride. Furthermore, they result in inferior colors and in pour point depressors which are not nearly as effective as those produced by my high temperature reactions. It should be particularly noted that in these high temperature reactions, particularly in the upper ranges thereof, no heat should be supplied. The reaction is endothermic and should be controlled by regulating the addition of the aluminum chloride and the heat input.

At temperatures heretofore used, about 130- 200 F., it has been necessary to use up to 10% aluminum chloride. I have found that from 250- 350 F. the amount of aluminum chloride can be cut down from one to four percent, one percent being required at high temperatures and three or four percent being required at temperatures of about 250 F. Increasing the aluminum chloride employed in the reaction changes the character of the sludge from a grainy consistency to a thick viscous mass.

An important feature of my improved high temperature process is the short-time interval which is required. Since the reaction is carried to completion in a very few minutes, it is possible to employ a continuous process for preparing the depressors. An example of such a continuous process is illustrated in the accompanying drawing.

Chlorinated Wax from storage tank 10 is withdrawn through pipe discharge heater 11 to pipe 12 and forced by pump 13 into mixer 14. Naphthalene is withdrawn from storage tank 15 through discharge heater 16 and pipe 17 and is forced by pump 18 into said mixer. The mixture of the chlorinated wax and naphthalene are then heated in exchanger 19 to the desired reaction temperature, which may be about 350 F., as hereinabove stated. This hot mixture is then passed through mixing chamber 20 wherein the aluminum chloride is added thereto through conduit 21. The aluminum chloride maybe distilled into the mixer as a vapor, it may be introduced as a liquid under pressure, or it may be introduced as a powder by means of a screw conveyor or by any other suitable means. The mixture of aluminum chloride with the other ingredients is passed under baille plate 22 into mixing chamber 23, which is provided with a suitable lstirrer 24 to prevent the sludge from settling out. Chlorine, hydrochloric acid and other gases are withdrawn from chamber 23 through vent pipe 25. The size of mixer 23 is regulated to give the desired time of contact, and the material leaving themixer may be passed immediately through pipe 26 to sludge separator 27. On the other hand, I may employ a plurality of stirring chambers of smaller capacity to prevent short circuiting and to insure the thorough reaction of all ingredients before the mixture enters the separator. For instance, I may pass the mixture from pipe 26 to pipe 28 and mixing chamber 29, which is provided with stirrer 30, gas vent 31 and outlet pipe`32 leading to the sludge separator. I have shown a two-stage stirring but it should be understood that any number of stirrers may be used.

The temperatures in the stirrers may be regulated by closed coils connected selectively with superheated steam or cooling water. 'I'he stirrers should preferably be thoroughly insulated, and usually I have not found it necessary to supply much heat at the mixing stage although, as hereinabove stated, the reaction is endothermic. It is undesirable to heat the reaction mixture to temperatures above 400 F.

At the high temperatures employed` and with low mass 0f aluminum chloride I obtain reaction products which are readily separated from aluminum chloride sludge and I find that the use of diluents and extracting solvents may be dispensed with entirely. 'Ihe separation may be effected by gravity in a horizontal settling tank 27, the sludge being removed from the base thereof by screw conveyor 33 and the reaction products being withdrawn from the top of the separator through pipe 34 and forced by pump 35 to mixer 36, wherein it is hydrolyzed or neutralized with hot caustic solution or with dry sodium hydroxide. 'Ihe neutralizlng agent may be introduced as a concentrated solution through pipe 37 into a mixer maintained at about 200 F., or dry caustic may be added and the temperature may be maintained anywhere from 200 to 400 F. This mixture is introduced into soda settler 38, from which gases are vented -through pipe 39, soda sludge is Withdrawn through pipe 40 and the neutralized mixture introduced from pipe 41 into mixer 42 together with water from pipe 43. The water is separated from the finished product in settling tank 44 and withdrawn through pipe 45. The nished product Pourex is withdrawn through pipe 46 to storage tank 47. It may be withdrawn when needed through discharge heater 48 and forced by pump 49 to mixer 50, which blends it with high pour point oil which is forced into said mixer by pump 51 from storage tank 52. 'Ihe treated oil which now is characterized by a low pour point is Withdrawn through pipe 53 to suitable storage tanks or for use.

The important features of my improved process include (1) the high temperature reaction range, (2) the avoidance of diluent and extracting liq uids, (3) the control of sludge quality by regulating aluminum chloride, (4) the high temperature hydrolysis or neutralization, (5) the continuous process, and (6) the vacuum distillation (if desired) to further concentrate the active ingredients.

As small an amount as .25% of Pourex will lower the pour point of Whiting Mid-Continent pale and red yoils as much as 70 F.-from +35 F. to 35 F. 'Ihe addition of .05% of the Pourex to No. 2006 red oil lowers its cold test from +28 F. to 10 F. with no color change. Pourex is not only effective on S. A. E. 10 and 20 lubricating oils, but it is very useful in S. A. E. 30, 40 and 50 oils, and even in bright stocks. In general, it appears to be about five times as efflcient as the best pour point depressor wllich has heretofore been commercially available.

Although Pourex is darker in color than other commercially available depressors, the quantities required are so much less that the color of the treated oils for a given pour point is much better. Furthermore, it is possible to improve the color of a treated oil by percolation with clay.

Although the exact chemical formula o1' Pourex cannot be determined, it invariably has a chlorine content of about one to three precent, and 'this chlorine content is not lappreciably affected even by heating over a long period of time following the reaction product. Furthermore, no corrosion results from the vvuse of Pourex even at temperatures up to 500 F.

While I have disclosed in detail a preferred embodiment of my invention it should be understood that I do not limit myself to this specific disclosure except as defined by the following claims, which should be construed as broadly as the prior art will permit. Instead of a specific chlorinated wax I may use chlorinated heavyI parafiin oils or various other waxes, such as petrolatum, Montan, ozocerite,retc. 'Ihe optimum degree of chlorination appears to be about ten or fifteen percent, although my depressors can be produced with chlorine concentrations from iive to thirty percent. Instead of using naphthalene as a condensing agent I may use diphenyl, chlorinated diphenyl, fluorine, phenanthrene, anthracene, coal tar residues, etc. I may alsohuse halogenated naphthalene as a condensation'reagent or I may use naphthenic or aromatic compounds equivalent to naphthalene in this reaction.`

I do not limit myself to the specific apparatus described herein. It is obvious that the process may be carried out in a batch-wise manner as well as continuously, and that certain features of my invention may be employed without employing all of the features thereof. For instance, cer tain amounts of diluent may be employed under the high temperature conditions provided that the diluent has a high enough boiling point. Further purification steps, such as solvent extraction with chlorinated organic solvent or precipitation from liquefied propane, etc. may be used for removing impurities and concentrating the active ingredients. Other expedients and equivalents will be apparent to those skilled in the art.

I claim:

1. The method of preparing a pour point depressor, which comprises heating a mixture of a chlorinated wax with an aromatic hydrocarbon to a temperature of about Z50-350 F., subsequently adding aluminum chloride to the heated mixture, maintaining the mixture of aluminum chloride with the heated mixture for a period of at least two to twenty minutes whereby there is a vigorous reaction and reaction products are formed, separating aluminum chloride sludge from reaction products, and neutralizing and removing uncombined chlorine from the reaction products.

2. The method of claim 1 wherein the aromatic hydrocarbon is naphthalene.

3. The method of claim l wherein the aromatic hydrocarbon is naphthalene and the halogenated. hydrocarbon is a chlorinated paraffin Wax having a melting point before chlorination of about 130 F. and a chlorine content of about ten to fifteen percent.

4. The method of preparing a pour point depressor, which comprises heating about 90 parts by Weight of chlorinated wax with about 10 parts by weight of naphthalene to a temperature of about 250350 F., subsequently adding to the heated mixture about 2 parts by weight of aluminum chloride, separating the aluminum chloride sludge from the reaction mixture, and neutralizing and removing the impurities from the recovered products.

5.' The method of claim 4 wherein the neutralization is effected at a temperature of about 20o-400 F.

6. The method of claim 4 wherein the mixture of aluminum chloride with heated chlorinated wax and naphthalene is mixed at said elevated temperature for a period oi about two to twenty minutes.

FREDERICK H. MACLAREN.

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