US2322036A - Condensation product - Google Patents

Description

Patented June 15, 1943 UNITED STATES PATENT. OFFICE CONDENSATION PRODUCT Eugene Lieber, West New Brighton, Staten Island,

N. Y., and Harry T. Rice, Roselle, N. J., assignors to Standard Oil Development Company, a corporation of Delaware No Drawing. Application November 16, 1939, Serial No. 304,704

6 Claims.

, eral formula R,--COR.', in which R is an aromatic group and R. is an alkyl group having at least carbon atoms, have a slight amount of pour-depressing properties. In other words, they have the characteristic of slightly reducing the pour point of waxy lubricating oils, when added thereto in small amounts such as 1 or 2%. (For measuring the pour point of an oil, the standard A. S. T. M. procedure is used.) However, such compounds are relatively weak and ineffective and have the further disadvantage of not being sufliciently soluble in mineral lubricating oils.

' It is also known that when the two raw materials used for preparing such ketones, namely, aromatic hydrocarbons and an acyl halide, are reacted in such proportions as to produce a compound having two acyl groups attached to the aromatic group, the resultant diacylated aromatic compound sometimes also has some pour depressor properties, although they are not sufficien tly potent in this respect to warrant commercial use, and in some cases the diacylated aromatic compound has even no pour-depressing properties.

It has now been found and is a primary object of the present invention, that by acylating an aromatic compound first. to a mono-acyl stage and then continuing the acylation to the diacyl stage, the resultant product is a highly efiective pour depressor. In other words, the diacylated compound made in two stages is unexpectedly much more potent as a pour depressor than the corresponding diacylated compound made in a single stage of acylation, by use of the proper proportion of the acyl halide.

For the sake of illustration, the two processes may be represented by the following two equations, of which A represents the one-stage or simultaneous acylation of the aromatic group with two acyl groups, and B represents the twostage acylation, namely, first acylating to the mono-acyl stage and subsequently acylating to the diacyl stage:

where R is an alkyl group of the same class as R, but not necessarily identical therewith. It is not known why the diacylated product B should be so unexpectedly superior to the diacylated product A, although it is possible that the acyl groups in these two products are in different positions with respect to each other around the aromatic group; for instance, in the one product -the acyl group may be in ortho position and in the other case in the meta position, or even in the para position. On the other hand, it is possible that after one acyl group has already been linked to the aromatic group, the reaction which takes place upon the further addition of acyl halide may be more complicated than represented by the simple Equation B given above. In any case, however, actual test data indicate that even when starting with different-types of raw material falling within the generic scope of this invention, the two-stage process is always very greatly superior to the one-stage process in respect to pour depressor properties.

Although the preparation of the mono-acyl aromatic compound is not per so within the scope of the present invention, it may be explained that one suitable method of preparing such compounds is to react a suitable aromatic compound suchas benzene, naphthalene, or derivatives thereof containing inert 'substituents, e. g. toluene, alpha-methyl naphthalene, hexyl benzene, etc, or mixtures thereof, with the desired acyl halide, in the presence of a suitable Friedel-Craftscondensing catalyst such as aluminum chloride. The reaction usually proceeds at room temperature, and inert solvents may be used if desired.

A detailed example of such a preparation will be given later.

For the preparation of the diacylated compound in a single stage or, in other words, the simultaneous combining of two acyl groups onto the aromatic group (process A), a substantially similar procedure may be used except that the amount of acyl halide used as raw material should correspond to about 2 mols of acyl halide to 1 mol of the aromatic compound; in order to insure completion of the reaction it may be neces sary to heat the reaction liquid for a somewhat;

longer time than necessary when to the mono-acyl stage.

Similarly, in carrying out the second stage of Process B, namely, the further acylation of a mono-acylated aromatic compound, the procedure used is substantially the same except that a mono-acylated aromatic compound is used as a raw material, and 1 mol of this compound is reacted with substantially 1 mol of the acyl halide to be used in combining the second acy group onto the aromatic compound. As a specific illustration of the invention, it has been found that when two stearyl (C1-1H35CO) roups are simultaneously combined with a benzene molecule (process A), the resulting product produced a pour point of +20 F. (when 2% of the addition agent was used in a waxy lubricating oil having an original pour point of +30 F); on the other hand, when only one stearyl group is only acylating combined onto a benzene nucleus, the resulting mono-stearyl benzene produced a pour point of +25 F. (in the same lubricating oil as used above) and when, according to the present invention, that mono-stearyl benzene was further acylated to a di-stearyl benzene (process B) the product produced a pour point of -30 F., which is vastly and unexpectedly superior to not only I aromatic groups are fairly effective as pour depressors, yet the corresponding compounds of the simpler mono-nuclear aromatic groups are extremely weak and ineffective; and yet by the process of the present invention those weak and ineffective rnono-acy1ated aromatic compounds may be converted into very potent pour depressors. Instead of benzene, other aromatic groups may be used such as naphthalene, diphenyl, anthracene, phenanthrene, toluene, phenol, aniline, cresol, etc.

The alkyl group R present in the acyl group of the mono-acylated aromatic compound should have at least carbon atoms and preferably at least carbon atoms, such as octadecyl, heptadecyl, cetyl, etc., although some of the lower groups such as lauryl may also be used. Instead of using compounds having relatively pure alkyl groups such as those mentioned above, mixtures may be used such as the mixed fatty acids ob tained from the oxidation of parafiin wax, these mixed acids being subsequently converted into the corresponding acyl halide as by treatment with phosphorus trichloride and then reacted with a suitable aromatic compound such as benzene to produce a corresponding wax-fatty acid ketone of benzene. The alkyl group of the acyl halide to be used in carrying out the second stage of the process B, namely, the primary process of the present invention, should be of the same general type as that just described, namely, having at least 10 carbon atoms and preferably at least 15 carbon atoms, but it need not be identical with the alkyl group present in the acyl group or groups already in the acylated aromatic compound.

Likewise, in carrying out the second stage of this process. a suitable Friedel-Crafts type catalyst should be used such as aluminum chloride, boron fluoride, zinc chloride, ferric chloride, titanium tetrachloride, boron chloride, anhydrous hydrogen fluoride, etc. Also, if desired, inert solvents or diluents may be used such as a kerosene or naphtha fraction, which have been highly refined by strong sulfuric acid or anhydrous aluminum chloride so as to be inert under the conditions of the present reaction. Other suitable solvents include tetrachlorethane, dichlor-benzene, or other halogenated hydrocarbon solvents or other inert liquids such as carbon disulfide, nitro-benzene, and the like.

Although obviously the amount of condensation catalyst to be used will vary to some extent according to the materials treated and according to the temperature and time of reaction, yet in general about 1 to 1.25 mols of catalyst should be used per mol of acyl chloride or halide used; this would correspond to approximately 44% to 55% by weight of aluminum chloride, for instance, in the case of stearyl chloride, the per cent of aluminum chloride being based on the amount of fatty acid chloride used.

The invention will be better understood from a consideration of the following experimental data:

Example 1.-Stearylation of mono-stearyl benzone.

The mono-stearyl ketone of benzene (phenyl heptadecyl ketone) having the formula was prepared from the following proportions of reagents:

Stearic acid grams 350 PCla do 395 Benzene do AlCls do 166 Solvent cc. of kerosene 500 The stearic acid was converted to stearyl chloride by treating with the PC13 on the water bath. The resulting stearyl chloride was decanted from the phosphorous acid into a mixture of the benzene and kerosene solvents in a suitable reactor. The aluminum chloride was now slowly added with suitable agitation. After the addition of the aluminum chloride, the reaction mixture was heated to about 220 F. and maintained thereat for about 5 hours. After cooling, the reaction mixture was neutralized with a mixture of water and alcohol and diluted with a further 500 cc. of kerosene. After settling, the kerosene extract was distilled with fire and steam to 600 F. to remove low-boiling products (chiefly solvent and unreacted stearic acid). A yield of 362 grams of mono-stearyl ketone of benzene was obtained, consisting of a light brown wax-like solid. When 1%, 2% and 3% of the mono-stearyl ketone of benzene thus prepared, were blended in a waxy oil having a pour point of +30 F., the pour points of the resulting blends were found to be +30 +25 F., and +l5 F., respectively, thus showing that the mono-stearyl benzene is only relatively weak as a pour depressor.

Now, according to the present invention, some of the mono-stearyl benzene thus produced was further acylated by treatment with an additional amount of stearyl chloride in the presence of aluminum chloride, using the following amounts of materials:

Mono-stearyl benzene 344 grams 284 grams acid 77 grams phosphorus trichloride Aluminum chloride 138 grams Solvent kerosene (pretreated with AlCla) The aluminum chloride was gradually added at room temperature and then the reaction mixture was heated to ISO-200 F. and maintained thereat for 4 hours, after which the catalyst was killed and the high boiling residue presumed to be essentially a di-stearyl benzene B was recovered from the reaction mixture (yield=503 grams), in a manner similar to that used above for the mono-stcaryl benzene. The resulting distearyl benzene B when added in 2% concentration to the same waxy lubricating oil base stock having a pour point of +30 IT, as used above, reduced the pour point of the blend to 30 thus showing a tremendously unexpected improvement in pour depressor properties as compared to the mono-stearyl benzene, which gave a pour point of only +25 F. This same distearic Stearyl chloride from Benzene 50 grams v 350 grams stearic acid Stearyl chloride from (2 mols) V 100 grams PCls A1C13 T 170 grams After addition of the AlCh the reaction mixture was heated to 200 F. and maintained thereat for 5 hours, after which the product (yield=295 grams) considered to be essentially a ell-stearyl benzene -A was recovered from thereaction mixture in substantially the same manner as described above. This (ii-stearyl benzene A when blended in 2% concentration in the same waxynoil as used above, reduced the pour point only to thereby indicating that it is very weak as a pour depressor. In other words, for some unknown reason, the di-stearyl benzene B of the present invention is-very markedly superior to either of the known products made from. the same raw materials. Example 2,-Acylation of benzene with paraffin wax acids.

Another set of tests were carried out exactly the same as under Example 1, except that instead of deriving the acyl group from stearic acid it was derived from the fatty acids obtained by the oxidation of parafiin wax (cut known as #6) using an acid fraction having the following properties: 1

The results of this series of tests were as follows: Pour point (F.)

Original waxy oil Original waxy oil+2%.,. mono-wax-ketone of benzene +5 Original waxy oil+2% di-wax-ketone of benzene A Original waxy oil+2%. di-waxketone of benzene B Better than 35 F. pour because the oil still pours freely at this tcmpcraturalbut this is the lower limit of the temperatures used in the standard A. S. T. M. procedure.

Thus in both Examples 1 and 2, the product mad according to the present invention by further acylation of a mono-acylated benzene gave unexpectedly superior pour depressing properties.

It will now be noted, from a consideration of the following experimental data concerning the acylation of naphthalene, that the invention is not limited to the preparation of compounds con taining only two acyl groups but it can also be applied to preparation of compounds containing three or even more acyl groups and such compounds can be prepared by acylating in two or more stages. For example, tri-stearyl naphthalene can be prepared either (1) by reacting naphthalene with 2 mols of stearyl chloride and reacting the resultant di-stearyl naphthalene A with another mol of stearyl chloride or (2). reacting naphthalene with 1 mol of stearyl'chloe ride, then reacting the resultant mono-stearyl naphthalene with another mol of stearyl chlo-*, ride to make a di-stearyl naphthalene B and finally, treating the latter with another mol of stearyl chloride. The products of either of these two processes (1) and (2) are both unexpectedly superior to a tri-stearyl naphthalene made in a single stage by treating naphthalene directly with 3 mols of stearyl chloride.

Example 3.--Stearylation of naphthalene toidistearyl naphthalene.

Using the same general procedure as described under Example 1, naphthalene was treated with stearyl chloride in two stages to make'di-stearyl naphthalene B and for sake of comparison also in one stage to make a di-stearyl naphthalene A. Both products 'weretested for pour point depressingproperties, along with the monostearyl naphthalene for comparison, using in all cases 2% of the addition agent dissolved in ';a waxy lubricating ,oil' base stock having a pour point of +30 F. The results were as follows:

' Pour pornt Original waxy oil +30 Original waxy oil 2% mono-stearyl naph 3 F thalene +25 Original waxy oil 2% (ii-stearyl naphthalene A +30 Original waxy oil 2% di-stearyl naphthalene B +30 It is noted that whereas the di-stearylnaphthalene A made by direct stearylation of naphthalene in a single stage had no pour depressing properties at all, the di-stearyl naphthalene B made by stearylation in two stages was a powerful pour depressor, only 2% of it reducing the pour point of the waxy oil from +30 F. to 30 F. This also illustrates clearly how the mono-stearyl naphthalene, which is itself only an extremely weak pour depressor, can be converted by further stearylation into a very potent pour depressor.-

Example 4 As an illustration of the application of this invention to aromatic compounds acylated to a content of 3 acyl groups, tri-stearyl naphthalene was produced by two different methods, the tristearyl naphthalene A being produced by direct stearylation of naphthalene in a single stage by using 3 mols of stearyl chloride per mol of naphthalene, and tri-stearyl naphthalene B being made by first stearylating naphthalene with 2 mols of stearyl chloride to make a distearyl naphthalene A and then further stearyla-ting this product with another mol of stearyl chloride. The results of pour-depressing tests on these two compounds were as follows:

Pour point F Original waxy oil +30 Original waxy oil 2% tri-stearyl naphthalene A +30 Original waxy oil 2% tri-stearyl naphthalene B -10 It is thus seen that the tri-stearyl naphthalene,B made in two stages is far superior to the tri-stearyl naphthalene A made in one stage because the latter is in fact not a pour depressor at all. Furthermore, the tri-stearyl naphthalene "13 is also far superior to the distearyl naphthalene A (made by stearylating naphthalene in one stage by using 2 mols of stearyl chloride) from which it was made because the latter had no pour-depressing properties at all.

When the product of this invention, which in effect is a wax modifier, is used as a pour depressor the amount of it to be added to a waxy lubricating oil will generally be between the limit of .01% and 10%, preferably about 0.5% to 3%, depending to a certain extent upon the amount of wax in the mineral oil and upon the degree of low temperature at which it is desired that the mineral oil be fluid.

Although it is primarily intended to use this wax modifier as a pour depressor in lubricating oils, it is also useful as an aid for settling, filtering, or centrifuging a wax, such as from a solution of hydrocarbon wax and an oil in a diluent such as naphtha, as used in dewaxing processes. For such a purpose, about 1% to 5% of the wax modifier is generally used, based upon the estimated amount of wax which is to be separated from the lubricating oil. The wax modifier of this invention is also suitable for improving the texture of wax, such as a parafiin wax, to be used for coating paper, etc., in which case the amount of wax modifier to be used should usually be within the range from about 1% to in the total composition of wax and modifier.

It is not intended that this invention be limited by any theory as to the mechanism of the operation of the invention, nor by any of the specific examples which have been given merely for the sake of illustration, but only by the appended claims in which it is intended to claim all novelty inherent in the invention as broadly as the prior art permits.

We claim:

1. A compound having the general formula R(COR') n where R is an aromatic group, R is an alkyl group having at least 10 carbon atoms and n is an integer greater than 1, said compound being made by acylating the aromatic group R in at least two stages.

2. The process which comprises acylating an aromatic compound with an acyl group having more than 10 carbon atoms besides the carbon atom in the CO group, to a mono-acyl derivative, and then further acylating said mono-acyl derivative with another acyl group having more than 10 carbon atoms in addition to the carbon atom in the CO group.

3. Process according to claim 2 in which R has more than 15 carbon atoms.

4. The process which comprises treating a compound having the formula RCOR' in which R is an aromatic group and R is an alkyl group having at least 10 carbon atoms, with an acyl halide having the formula RCOX, in which R is an alkyl group having at least 10 carbon atoms and X is an halogen atom.

5. A di-wax ketone of benzene made by acylation of a mono-wax ketone of benzene by a wax acid halide.

6. A tri-stearylated naphthalene made by stearylation of naphthalene in at least two stages.

EUGENE LIEBER. HARRY T. RICE.