Patented Nov. 26, 1946 I ? 2,411,502 STATES ' PATENT. ' OFFICE TREATMENT OF mnpngnoips Lawton A. Burrows, Woodbury,=N.‘J., 'assigno'r to . E. I. duPont de Nemours & Company, Wilming- ' ton, Del., a corporation of Delaware 7 g‘ , . No Drawing. , Application June V15, 1945‘, ' Serial No. 599,745 g’ 6 Claims. (01. 19,6713) 1 2 This invention relates to a novel method of treating and re?ning mineral oils and more par perature of 120° F. was maintained, at which tem perature complete solution had resulted. The ticularly to a method of dewaxing such oils. solution was then allowed to cool for one hour at The problem of separating wax-like constitu a temperature of around 32-37 ° R, where precip ents from mineral oils has assumed much im itation of wax resulted. The solution was ?ltered, portance to the petroleum industry in recent and the wax removed was transferred to another years. The methods proposed and applied for vessel, from which the nitrocyclohexane was re accomplishing this result have in general com moved by evaporation. The ?ltrate was trans prised (1) cooling of the liquid oil, with crystal ferred to a ?ask and the nitrocyclohexane dis lization of the wax at the low temperatures ob 10 tilled off under 15 mm. pressure. The pour point tained, (2) the use of solvents for selective solu ‘of the recovered oil Was 45° F. The amount of tion of: certain ingredients and the separation wax separated from'the oil was 11.5%. of the oil into two distinct layers, or (3) the com-' A similar procedure in which use was made of bination of selective solvents and refrigeration. a two-component solvent commonly used in oil The last method has been the one'most success fully applied. In all procedures, the waxy con 15 re?ning gave a pour point for the recovered oil of 50° F. and a wax removal of 10%. stituents have been separated from the body of Nitrocyclohexane from the process described is the mineral oil and, where present, the solvent recovered in large part and can be used repeat has been removed. While various solvents have edly in successive operations, without removal of been used, the results have not been completely small amounts of hydrocarbon. Eventually puri satisfactory because of the dif?culty of ?nding a ?cation of the repeatedly used solvent may ‘be solvent possessing all the desirable character necessary. istics. The employment of nitrocyclohexane for pur An object of the present invention is a, new poses of .wax removal has been emphasized in and improved method of treating mineral oils and 25 the foregoing, and it is this use which is partic separating various constituents, in order to obtain ularly important. The invention will include, a re?ned product. A further object is such a however, selective separation of any ingredients method, which employs for the purpose a solvent , by means of nitrocyclohexane. It may be de of superior properties. A still further object is a sired,'for example, to separate mineral oils into method of dewaxing mineral oils. Additional ob portions richer respectively in para?in or naph jects will be disclosed as the invention is de thenic hydrocarbons, and my invention is in scribed more at length in the following. tended to cover such a process. Moreover, in I have found that the foregoing objects are addition to the removal of waxes by refrigeration attained when the mineral oil for treatment is of the solution in nitrocyclohexane and precipi admixed with nitrocyclohexane and maintained 35 tation of the Waxy constituents, the separation‘ at a sufficiently elevated temperature to assure may be into two liquid layers, one higher than substantial solution or miscibility, and the solu the other in wax content, rather than separation tion is then cooled to a temperature at which of a. solid from a liquid. It will be understood, -‘ segregation into more than one portion results. therefore, that the invention covers all proced ‘The segregated portions are separated and the ni 40 ures whereby selective extraction and concen trocyclohexane recovered from the respective por tration are effected by use of the solvent de tions, preferably by distillation under reduced pressure. In the dewaxing of oils, the wax por scribed. Whereas, also, the example has cited a single batch extraction of the wax content of tion will ordinarily precipitate out in solid form the oil, it will frequently be desirable to employ on cooling and will be separated from the oil by 45 a multiple extraction process, wherein fresh sol_ ?ltration, centrifuging, or like procedures. vent is caused to obtain extractable material from The‘ following will serve as a speci?c example ra?inates from previous extractions. vIt will be of a procedure for carrying out the invention. This is, of course, merely illustrative and is not to betaken as limiting in any way. - A sample of Pennsylvania wax distillate was used, having a pour point of 105° F. and a viscos ity of 60 Saybolt Universal seconds at 210° F. The oil was mixed with nitrocyclohexane in the proportion of 30 to 70 respectively, and a tem appreciated that the process described is- an ef fective method of decreasing the pour point of 50 oils. Nitrocyclohexane is excellently adapted for use ‘in the dewaxing of oils because of its properties as a solvent, being miscible in all proportions with such other solvents as ethanol, ether, ace 55 tone, benzene, kerosene, and the like. While it 2,411,502 4 has been disclosed as the sole solvent in extras‘ ' tive dewaxing processes, it may if desired be used in accompaniment with other solvents; such as, nitrobenzene, benzene, and the like. It will be understood, therefore, that I intend to be limited only by the following claims. I claim: I 1. The process of treating mineral oils and sep arating various constituents therein contained, which comprises mixing the mineral oil with ni trocyclohexane and effecting substantial solution therebetween, cooling the solution to a tempera ture at which segregation into more than one portion results, and separating said segregated portions. 2. The process of claim 1, in which two layers of liquid are formed on cooling of the solution. 3. The process of claim 1, in which solidi?ca tion of a. portion of the mineral 011 takes place on cooling. 4. The process of re?ning mineral oils and sep aratlng wax therefrom, which comprises e?ect ing substantial solution of said oil in nitrocyclo hexane at a temperature su?iciently elevated therefor, cooling said solution to a temperature at which separation of the wax in solid form takes place, and removing the separated solid from contact with’ substantially the bulk of the solu tion. ' 5. The method of claim 4, in which the nitro cyclohexane is recovered from the respective liq uid and solid separated portions. 6. The method of claim 4, in which the nitro cyclohexane is removed from the respective por tions by distillation under reduced pressure. LAWTON A. BURROWS.