US2081518A - Lowering pour point of oil - Google Patents

Description

May 25, 1937. M. L. WADE 2,081,518

LOWERING POUR POINT OF OIL Fiied Sept. 4. 1934 0.15 7 of Depres 0.3% of Mixed Depressan 0.45% Depre hei Pour Point "F N O .50 7O Montanwax 100908070605040302010 OPourex INVENTOR. Maner L. Wade BY%,& 1

4 A TTORNEY.

Patented s 25, 193

UITED STATES PATENT OFFICE- v LOWERING POUR POINT OF OIL Manet L. Wade, Long Beach, Calif., assignor to Union Oil Company California, Los Angeles. Calif., a corporation of California Application September 4, 1934, Serial No. 742,625

This invention relates to the production of low pour point lubricating oil and to pour point depressing agents as compositions of matter.

One of the desirable characteristics of a high grade lubricating oil is a low pour point, i. e. a low temperature at which the oil congeals or ceases to flow. The pour point of an oil is measured according to the method specified by the American Society of Testing Materials D-9730.

In the production of lubricating oils fromwaxy fractions it is customary at the present time to remove a substantial quantity of the wax from the oil in order that the final product will have a low pour point. This is usually accomplished by adding a suitable diluent such as naphtha to the waxy oil, chilling the mixture to a temperature suficiently low to precipitate the wax and then removing the wax from the chilled mixture by settling, centrifuging or filtering. This operation is not only expensive but removes from the oil constituents which have a high lubricating oil value. oil fractions are characterized by a flat viscosity temperature slope, i. e. they have a low viscosity gravity constant as measured by the method prescribed by Hill and Coates in the Journal of 'Industrial and Engineering Chemistry, volume 20, page 6 41 for 1928.

Oils which contain wax have a lower viscosity gravity constant than that of the oil itself after the wax has been removed. Therefore where it is desired to produce oils of the lowest viscosity gravity constant it is undesirable to remove the wax from the oil.

Furthermore the separation of the wax from wax bearing oil results in a lower yield of the finished oil. The removal of the wax amounts to an appreciable lowering of the yield and furthermore an additional loss is occasioned by the oil which is contained in the wax removed from the I have discovered a method of lowering the pour point of oil wherein it is unnecessary to re- -move all of the wax from'the oil. I have discovered certain agents or materials, which, when added in relatively small amounts to oils having a highpol'ir point, cause a substantial lowering of the pour point of the oil.

I have discovered that Montan wax is an eiiective pour point depressant for oils which have a high pour point. When a small quantity of Montan wax is added to an oil. having a high pour point the pour point of this mixture is substantially lowered. For example a Santa. Fe Springs waxy distillate having a pour point oi Most waxes contained in lubricating 50.0 F. was mixed with 0.3% of refined Montan wax and the pour point of this mixture or blend was found to be 10.0 F.

Montan wax occurs in lignite and is extracted therefrom by means of volatile solvents. Refined Montan wax has a melting point (Ubbelohde) between 80 and 86 c., an acid number of 64.0 and a saponification number of 67.0.

Crude or unrefined Montan wax may also be advantageously employed to lower the pour point of oil. However this material is not as effective as the refined product. Crude Montan wax has a melting point of about 84 C. (Ubbelohde) an acid number of 26 and a saponiflcatlon number of 92.0.

It is therefore an. object of this invention to lower or depress the pour point of oil by the use of Montan wax.

I Have also discovered that mixtures of certain materials are more eflective tor lowering the pour point of 011 than the respective materials comprising the mixture.

It is therefore an object of this invention to produce pour point depression agents comprising mixtures 01 materials which conjointly are efictive in lowering the pour point of oil.

It is another .object or this invention to produce pour point depression agents from mixtures of materials which individually do not lower the pour point of oil to as great a degree as the respective es.

It is a further object of this invention to lower the pour point 01 lubricating oil by the addition of a material to said oil comprising a plurality of materials which in admixture with the oil cause a substantial lowering oi. the pour point of the oil.

It is another object of this invention to produce relatively low pour point lubricating oil from oil having a-relatively high pour point which comprises adding to said high pour point oil a mixture of materials which conjointly are effective in lowering the pour point of said oil.

It is another object of this invention to lower the pour point of oil by the addition to said oil of a mixture of materials which individually have little or no pour point depressing eiiect upon said oil but which in admixture cause a substantial lowering of the pour point of said 011.

The following table shows'the pour point depressing qualities or characteristics of certain materials when added to a high pour point lubricating oil traction and the pour point depressing qualities or characteristics of mixtures of these materials when added to the high pour point oil.

"The oil used in conjunction with the pour point depression agents shown in this table is a Santa -Fe Springs distillate having a pour point oi. '75 as shown in Test 1 of this table.

Table Pour point of the oil blended with the depressant -F.

Pour oint de ressant wei ht 7 added to Test p the oil g None 0. 5% condensation product 0.25% condensation product 0. refined Montan wax 1. 0% of an extract from cracked petroleum pitch 0.5% extract from cracked petroleum pitch 0. 5% refined Montan wax l. 0% of a cracked distillate 5% cracked distillate 0. 5% refined Montau RX I. G. E. wax cracked distillate 0. 5% I. G. E. wax" I. G. 0. P. wax condensation product 0. 15%I G 0. wax I. G. B. wax 15% condensation product 0. 15% I. G. B. WBX .3% I. G. S. wax 0. 15% condensation product 0. 15 I. G. S.

WBX 0.30% ester gum 0. 15% condensation product 0. 15% ester gum 0. 30% stearic acid 0.15%, condensation product, 0.15% stearic flil 0. 30% copal 0. 15% cope] 0. 15% condensation product 0. 30% condensation product 1. 0% polymerization product 0. 6% polymerization product Montan wax 1.0% acetone extract irom,wax 0. 5% Montan wax o. 5% acetone, extract from wax. 0. 3% Carnauba wax 0.15% Carnauba wax 0 6% condensation product 0. 50% Montan wax cam $ & 8 8E G5 5; 85:5 55:00:: -10: cm:- carer- $5" 88% 5'8 38 d2 as .which are produced according to the process described in the aforementioned patent.

The cracked petroleum extract shown in Tests 4 and 5 of the above table was made by topping a cracked asphaltic residue to 55% bottoms and a melting point ,(Ball and Ring) of 314 F. and then extracting these bottoms at ordinary temperature with naphtha to dissolve the oil-like bodies and precipitate the black or asphaltic bodies. The fractions dissolved in the naphtha are then recovered by distilling the naphtha from the solution. It may also be prepared by extracting the asphaltic bottoms with light lubricating oil and dectanting the lubricating oil solution away from the black residue.

The cracked distillate employed in Tests 6 and 7 of the above table was made from a cracked asphaltic residue which had previously been topped to 65% overhead and 35% bottoms. The bottom fraction had a melting point of about 325 to 350 F. (Ball and Ring). bottoms were distilled and the overhead fractions recovered from this material were employed inthe manner shown in the above table under Tests 6 and 7. The overhead fractions from the35% The 35% 1931, issue of the Chemical Trade Journal. These waxes are products of esterification of montanic alcohols with montanic acids. The montanic acids (which are high fatty acids with a high melting point) are obtained by the oxidation of the hydrocarbons in .lignite, while the montanic alcohols are made by the reduction of the corresponding acids under a high pressure. Therefore, when I employ the term "products of esteri- ,fioation of montanic alcohols with montanic acids in the specification and claims, I am referring to the above described materials produced as described in the aforementioned articles.

The wax employed in Tests 8 and 9 of the above table and'denoted therein as the I. G. E. wax, has an acid number of 14.3, a saponification number of 142, a. melting point (Ubbelohde) of 166 F., a specific gravity of 1.01-1.02, an esterification index of 140-155, and contains about 7 to 10% of unsaponifiables.

The wax employed in Tests 10 and 11 of the above table, and denoted therein as the I. G. O. P. wax, has an acid number of 13.8, a. saponification number of 113, a. melting point (Ubbelohde) of 219 E, specific gravity of 1.03-1.04, an esterification index of -120 and a 7 to 10% content of unsaponifiable materials.

The wax employed in Tests 12 and 13 of the above table and denoted therein as I. G. B. wax has an acid number of 57.8, a. saponification number of 148, a. melting point (Ubbelohde) of 177.5 F., specific gravity 0.98, an esterification index ofto and a 22% content of unsaponiflable materials.

The wax employed in Tests 14 and 15 of the above table has anacid number of 143, a saponi-- and 24 of the above table is a synthetic oil having the following characteristics:

Gravity A. P. I. at 60 F 22.0 Viscosity, Saybolt universal at 210' seconds..' 687 Flash, F. (Cleveland open cup) 390 Fire, F'. (Cleveland open cup) 460 Four point, "F 30.0 Conradson carbon value, percent 0.39 Acid number -s 0.47 Saponification number 72.0

this material is made from vegetable and mineral oil and is fully described in Kohlenwasserstofiole und Fette by D. Holde, 7th edition at page 372. According to the description by Holde the aforesaid polymerization product is prepared by the blow discharge of a mineral or fatty oil, the process, through ionic discharge, causing a formafore when I employ the term "polymerization .produc in the specification and claims I am re-' tion of polymerization products of high molecular weight, as well as of a very high viscosity. Thereferring to the materials produced according to the description of Holde in Kohlenwasserstoffole und Fette, 7th edition, at page 372.

The acid numbers and saponification numbers of the materials shown in this specification were.

1 solved fractions were separated from the undissolved material. The acetone solution was distilled to remove the acetone and the extract re covered was employed as shown in Tests 25 and 26 of the above table.

From an inspection of the data in the table it will be noted that the mixtures of materials are more effective for lowering the pour point of oil than the individual materials.

For example condensation product mixed wit Montan wax,. products of esterificatlon of montanic alcohol with montanic acids, ester gum, stearic acid, copal or polymerization product is more effective inlowering the pour point of oil than any of the single members of this group.

Furthermore it will be noted from the table that a mixture of cracked distillate and a product of esterification of montanic acid with montanic alcohol is more efiective for lowering the'pour point of lubricating oil than either cracked dis tillate'or a product of esteriflcatlon of montanic' acid with montanic alcohol (Tests 6, 8, and 9);

extract from cracked petroleum pitch mixed with Montan wax is more efi'ective than the cracked extract alone (Tests 4 and 5) cracked distillate mixed with Montan wax is more effective than cracked distillate alone (Tests 6 and 7) and acetone extract from wax mixed with Montan wax is more effective than the wax extract alone (Tests 25 and 26).

Furthermore from Tests 22, 27, and 28 it will be seen that a mixture of carnauba wax and condensation product is decidedly more efiective in lowering the pour point ofthe oil than either condensation product or carnauba wax.

The above examples are merely illustrativeand are not to be construed as limitations upon the invention which I claim.

The effect of mixed pour point depression agents ormodifiers upon the pourpoint oflubricating 'oil is mso shown in Graphs A, B, and C of Figure 1. The ordinate of this figure shows the pour point of the oil and the abscissa shows the composition of the mixed pour point depressant added to the oil. Graphs A, B, and C show the effect of adding 0.15%, 0.30%, and 0.45% respectively of a mixed pour point depressant containing condensation product and Mont-an wax in the respective proportions shown on the ordinate.

F.; the. addition to the oil of 0.15% of a mixture of Montan wax and condensation product containing 25% Montan wax and 75% condensation product lowered the pour point of the oil to 45 F. the addition of 0.15% of a mixture of Montan wax and condensation product containing 35% Montan wax and 65% condensation product lowered the pour point of the oil to 20 F.; the addition of 0.15% of a mixture of Montan wax and condensation product containing 75% Montan wax and condensation product lowered the pour point of the oil to 20 F.; and, the addition of 0.15% Montan wax to the oil loweredthe pour-point to 40 F. From this graph it is apparent that mixtures of condensation product and Montan wax are more effective than either of these materials.

Furthermore it willbe noted that 0.15% of this mixed modifier is most effective when the proportion of Montan wax contained in the mixture lies between the proportions of 25% and 75%.

The data presented on Graph B shows the effect of adding 0.30% of a mixture of condensatlon product and Montan wax upon the pour point of the oil. From this graph it will be noted that this mixture is most efiective for lowering the pour point of the oil when the proportion of Montan wax contained in the mixture lies between 50% and 75%.

The data presented in Graph C shows the effect of adding 0.45% of a mixture of condensation product and Montan wax upon the pour point of the oil. From this graph it will be seen that this mixture is most effective for lowering the pour point ofthe oil when the proportion of Montan wax contained in the mixture lies between 25% and 75%.

From an inspection of Graphs A, B, and C of the figure it will also be noted that increasing amounts of these mixed pour point depressants added to the oil produces an increase in the lowering of the pour point of the oil.

From a consideration of the data presented in the figure it is seen that eutectic mixtures are obtained between the wax, condensation product and Montan wax. Furthermore it is seen from this figure that the pour point of the eutectic mixturedepends upon the relationship between the quantities of the respective depressants contained in the mixture and that there is an optimum range of proportions within which these pour point depression agents must exist in the oil in order to obtain maximum lowering of the pour point. For example the optimum range for densation product within these limits have the lowest pour points which can be produced by mixing the waxy oil with condensation product and Montan wax.

Thelowest pour point "eutectoids to' be obtained in the mixtures shown on Graph B will exist when the Montan wax or condensation product contained in: the Montan wax-condensation product mixture constitutes from 50% to 75% of the mixture. Furthermore the lowest pour point eutectoids to be obtained in the mixtures shown on Graph C will be when the Montan wax or condensation product constitutes from 25% to 75% of the mixed depressant. By the term ,eutectoid I mean oil and;

wax Omixed with a plurality of pour point depressing agents compounded in such proportions add a plurality of pour point depressing agents to waxy oil in amounts sufficient to produce a eutectic mixture having a minimumpour point.

The pour point depression agents produced according to this inventionhave been found to be more efiective in lowering the pour point of oil containing wax or the crystalline type than upon oils containing wax of the ceresin type. The

crystalline waxes are usually found in overhead- 20 distillates and are low melting points.

I claim: 1. A composition of matter comprising a wax bearing mineral oil blended with 0.15% to 0.45% 25 of a mixture of Montan wax and a condensation product obtained by reacting an aromatic hydrocarbon with a chlorinated aliphatic: hydrocarbon in the presence of a metallic halide oi the Friedel-Craft-catalyst type.

2. A composition of matter comprising, a wax bearing mineral oil blended with about 0.15% to 0.25% of a condensation product obtained by reacting an aromatic hydrocarbon with a chlorinated aliphatic hydrocarbon in the presence of characterized by relatively ametallic halide of the Friedel-Craft catalyst type and blended with one of the members selected from the group consisting of a montanic alcohol esterof montanic acid, carnauba wax, copal and Montan wax, said composition of matter 5 being fluid at ordinary atmospheric temperature.

3. A composition of matter comprising a wax bearing mineraloil blended with 0.15% to 0.50%

of Montan wax and with a small quantity of one of the members selected from the group consist- 10 ing of cracked petroleum pitch, extract from cracked pitch, cracked petroleum distillate, a condensation product obtained by reacting an aromatic hydrocarbon with a chlorinated aliphatic hydrocarbon in the presence of a metallic halide of the Friedel-Craft catalyst type, and a polymerization product obtained by volatilization of vegetable and mineral oil, said composition of matter being'fiuid at ordinary atmospheric temperature.

4, A composition of matter comprising a wax bearing mineral oil blended with about 1.0% of I a mixture of Montan wax and an extract ob tainedfrom cracked petroleum pitch.

5.'A composition of matter comprising a wax; bearing mineral oil blended with about 0.3 %--.qf a mixture of a condensation product obtained by reacting an aromatic hydrocarbon with a chlorinated aliphatic hydrocarbon in the presence of a metallichalide' of the Friedel-C'raft- "3'0 catalyst type and anester of montanic alcohol and montanic acid. v g

i MANER L. WADE.

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