/ Patented Nov. 5, 1946 ' 2,410,578 UNITED STATES, ' PATENT OFFICE‘, MINERAL OIL COMPOSITION John J. Giammaria, Woodbury, N. ., assignor to Socony-Vacuum Qil Company, Incorporated, a corporation of New York , No Drawing. Application September 28, 1944, Serial No. 556,287 10 Claims. (Cl. 252-56) i 2 This invention relates to mineral oil composi tions and more particularly relates to viscous mineral oil fractions containing small amounts of an added material which imparts improved Representative of the aliphatic acids which form one component of the esters contemplated >...\ herein are palmitic, stearic, arachic, behenic, lig noceric, cerotlc, melissic, etc. Preferred of such pour or ?ow characteristics thereto. acids, however, are palmitic and stearic. With respect to the second component of the As is well known in the art, mineral oil frac tions, such as those derived'from paraffin base aforesaid esters, namely, lignin, it is recognized crudes which have been re?ned for use as lubri ‘that the structure thereof is still in the con troversial stage. Yet, many aspects of its nature cants, normally contain an amount of wax- such that,they congeal or become non-flowing at tem 10 are known and are such as to de?nitely establish peratures only slightly below normal tempera ‘its identity in the art. It is known that it occurs tures. Obviously, oil fractions so characterized in plant life, such as shrubs, straw, trees, such are impractical for general use. Although it is as hardwoods, typi?ed by oak, and softwoods typi possible to remove an appreciable amount of this ?ed by pine, etc.; and may be extracted there wax by additional re?ning operations and there 15 from by various means. For example, lignin by materially reduce the “pour point" of the oil, may be extracted from plant life with cold con such re?ning operations are expensive and, in addition, seriously reduce the lubricant qualities centrated acid, with hot caustic solutions, etc. It is also known that lignin differs from carbohy of the oil. Apparently, the wax present in the oil drates in its carbon and hydrogen content, an solidi?es in the form of a lattice-like structure 20 alyses for lignin generally ranging from about 60 and encloses the oil, thereby undesirably con per cent to 65 per cent carbon and 5 per cent to 6 gealing the oil, yet contributing desirable lubri per cent ,carbon, with the remainder oxygen. It cating qualities thereto. Accordingly, rather than has also been. established that the methoxyl resort to expensive re?ning operations to remove (-—OCH3) content varies from about 14 per cent the wax and sacri?ce some of the lubricating 25 to about 21 per cent indicating the presence of 5 quality of the oil, it has become the practice to or 6 methoxyl groups per unit molecule. Analyses allow the wax to remain in the oil and to counter have also indicated that lignin is-characterized act its undesirable e?ect upon the pour charac with 4 or 5 hydroxyl (-OH) groups. It has teristics of the oil by incorporating therein a - rbeen suggested, for example, that lignin obtained small amount of an agent capable of improv 30 from hardwoods has 6 methoxyl groups and 5 by ing the said pour characteristics. Improving droxyl groups; whereas lignin obtained from soft agents of this type are generally described as woods, usually has 5 methoxyl and 5‘ hydroxyl “pour depressants” in view of their ability to groups. The molecular weight of lignin obtained modify or retard wax crystallization so that im-v from various plants has varied considerably, pairment'of ?ow does not take place except at 35 workers in this ?eld reporting molecular weights temperatures well below those normally encoun from about 780 to about 1800. Strong acids tered in the use of the oil. The present inven have little or no effect upon lignin, as have most tion has to do with an improving agent of this organic solvents. Lignin is illustrated herein type which is greatly effective in very small quan after in the examples. "I: tities. ' 40 The preferred method of preparing the esters The present invention is predicated upon the discovery that a mineral oil fraction containing contemplated herein is that wherein lignin is dis solved ~ln pyridine and is heated at an elevated a small amount of an ester of lignin and of an temperature with an acid halide, followed by aliphatic acid having at least about 16 carbon precipitation of the‘ ester so formed upon the atoms is characterized by an appreciably lower 45 addition of water. The ester so. precipitated is pour point than is the mineral oil fraction alone. then puri?ed; it is washed with water and there While all esters of the aforesaid class possess pour .after dissolved in hot benzol. The benzol solupoint depressant properties, those of certain sub tion so obtained is ?ltered, and the ?ltraterdise classes are particularly effective in this regard. tilled to remove benzol therefrom. At this stage, Lignin esters wherein at least 3 hydroxyl groups 50 the ester is relatively pure and may be used here of the lignin are esteri?ed with a saturated mono in; however, it may be further puri?ed whensdis carboxylic aliphatic acid of the aforesaid type solved in ether, then waished'withsodiumear are outstanding and particularly so are those bonate solution, dried‘ with a drying agentsuch esters wherein the lignin is obtained from hard wood. ' . as calcium chloride and heated to evaporates'ether 55 therefrom. _- 5 at ' To facilitate handling, the esters may be pre pared in an oil blend. For example, after lignin has been reacted with an acid halide, three parts by weight of mineral oil may be added to the re action mixture and the puri?cation procedure, de Table on Cone. weight PM: gm" per cent scribed ,above, may then be followed. _ In this way, the ?nal product is obtained as a 25 per cent blend in mineral oil, which is more con venient to work with than a more concentrated, or pure, product. Illustrative of the lignin esters and of their ........ -- +20 +15 . 10 -m .20 ~20 ........ ._ examples provided below. The lignin used in the preparation of the esters described below is ob ' 0. 05 . a) methods of Preparation are those described in the . tained from hardwood such as spruce chips ac Lignin ester -s +5 .05 -5 . 10 ~15 .20 --15 From the foregoing data, it will be apparent that lignin esters of the class contemplated here liquor obtained by cooking spruce chips, that is in depress the pour points of oils to which they hardwood chips, in an autoclave, under pressure, are added to a substantial degree, although used therein in but minute quantities. for several hours with a 5 per cent sodium hy droxide solution was evaporated until the speci?c 20 Not only are the aforesaid lignin esters of value gravity was about 1 and the total solids about 20 as pour point depressants, but they are of value cording to the following procedure. A soda black 15 per cent. Carbon dioxide was passed into the so lution until the pH thereof was lowered to about as wax modi?ers for other purposes such as de waxing aids in oil re?ning and the like. In gen 8.5, whereby a portion of the lignin separated out. _ eral, they may be used in all cases wherein it is The lignin so separated was coagulated by heat 25 desired to modify the crystal structure of paraf ing the same to about 100° C. and thereafter cool ing it to about 50° C. It was then ?ltered, washed with water, and then washed with dilute min eral acid. It was ?nally washed with water and dried. The lignin so obtained had a molecular 30 weight of about 850. ' Examru: ONE Preparation of lignin 'stearate Forty grams of lignin, described above, was dis ?n wax. They may be used in mineral oil frac tions in concentrations of from about 0.05 per cent to about 10 per cent depending upon the character of the oil fractions and their conditions of use. Satisfactory results, however, are gen erally obtained with concentrations of the order of 005-02 per cent. It is to be understood that while certain pre ferred ‘procedures for synthesizing the improving 35 agents contemplated herein and certain illustra solved in 30 grams of pyridine and 100 grams of dioxane, and warmed to about 50° C. Eighty grams of stearyl chloride was then added slowly, tive reactants which may be employed have been .13‘. .The results of pour tests upon oil blends of these oils and typical ligm‘n esters are provided mono-carboxylic aliphatic acid having at least about 16 carbon atoms, at least 3 hydroxyl groups of the lignin being esteri?ed with the said acid. recited herein, the invention is not to be con strued as limited thereto. Rather, the invention is to be broadly construed in the light of the lan during a. thirty minute period, to the lignin dis solved in pyridine and dioxane. After all of the 40 guage of the appended claims. I claim: stearyl chloride had been added, the resulting 1. A mineral oil composition comprising a vis mixture was heated to 100° C. and was main cous mineral oil fraction having in admixture tained at the latter temperature for about 2 therewith a minor proportion, suf?cient to de- hours. Thereafter, the mixture was cooled and press the pour point of said oil fraction, of a diluted with water whereupon the crude product, lignin ester of an aliphatic acid having at least lignin stearate, precipitated out of the mixture. about 16 carbon atoms. The crude product was washed with water and 2. A mineral oil composition comprising a vis then dissolved in benzol. The benzol solution cous mineral oil fraction having in admixture thus formed was ?ltered and the benzol was dis therewith a minor proportion, from about 0.05 tilled from the ?ltrate to obtain substantially percent to about 10 percent, of a lignin ester of pure lignin stearate. The product is a hard, an aliphatic acid having at least about 16 carbon ‘brown. wax-like solid. atoms. 3. A mineral oil composition comprising a vis ExAMPLn 'Iwo 55 cous mineral oil fraction having in admixture Preparation of lignin. palmz‘tate therewith a minor proportion, su?icient to de-‘ press the pour point of said oil fraction, of a. lignin ‘Thirty-one grams of lignin, described above, ester of a saturated mono-carboxylic aliphatic were dissolved in 25 grams of pyridine and 100 acid having at least about 16 carbon atoms. grams of dioxane, and reacted with 50 grams of 4. A mineral oil composition comprising a palmityl chloride as described in Example One 60 viscous mineral oil fraction having in admixture above. The product, lignin palmitate, is also a therewith a minor proportion, su?icient to de hard, brown, wax-like solid. press the pour point of said oil fraction, of an The following data illustratethe pour point ester of lignin and of a saturated mono-carboxylic depressing action of the lignin esters contem plated herein upon mineral oils of the motor lu 65 aliphatic acid having at least about 16 carbon atoms, at least 3 hydroxyl groups of the lignin bricant type. The oils used in these tests were: being esteri?ed with said acid. oil A, a Mid-Continent, solvent-re?ned, S. A. E. 5. A mineral oil composition comprising a vis 30 grade. oil having a Saybolt Universal viscosity of 65seconds at 210° F., and a pour point of +20" - cous mineral oil fraction having in admixture F.; oil B, a chlorex-re?ned Pennsylvania S. A. E. 70 therewith a minor proportion, sui?cient to de 10>gradeoil having a Saybolt Universal viscosity press the pour point of said oil fraction, of an ,of 45 seconds at 210° F. and a pour point of +5° ester of a hardwood lignin and of a saturated in the table below. . 2,410,578 6. A mineral oil composition comprising a vis cous mineral oil fraction having in admixture therewith a minor proportion, su?icient to de press the pour point of said 011 fraction, of an ester of a hardwood lignin having a molecular weight of about 850' and of a saturated mono . 6 i press the pour point of said oil fraction, of a lig nin stearate, said lignin having a molecular Weight of about 850 and having at least 3 hy droxyl groups esteri?ed with said acid. 9. A mineral oil composition comprising a vis- _ cous mineral oil fraction having in admixture carboxylic aliphatic acid having at least about 16 therewith a minor proportion, sufficient to de carbon atoms, at least 3 hydroxyl groups of the press the pour point of said oil fraction, of an lignin being esteri?ed with said acid. ester of a hardwood lignin and of palmitic acid, '7. A mineral oil composition comprising a vis-_ 10 at least 3 hydroiwl groups of the lignin being es cous mineral» oil fraction having in admixture teri?ed with said acid. therewith a minor proportion, su?icient to de 10. A mineral oil composition comprising a vis press the pour point of said oil fraction, of an cous mineral oil fraction having in admixture ester of a hardwood lignin and of stearic acid, at therewith a minor proportion, su?icient to de least 3 hydroxyl groups of the lignin being esteri 15 press the pour point of said oil fraction, of a ?ed with said acid. lignin palmitate, said lignin having a molecular 8. A mineral oil composition comprising a vis weight of about‘850 and having at least 3 hy cous mineral oil fraction having in admixture droxyl groups esteri?ed with said acid. therewith a minor proportion, suiiicient to de . JOHN J‘. GIAMMARIA.