US2174246A - Method for producing wax modifying agents - Google Patents

Description

Patented Sept. 26,1939

UNITED STATES PATENT OFFICE Eugene Lieber,

Linden, and Martin M. Sadlon,

Roselle Park, N. J., assignors to Standard Oil Development Company, a corporation of Delaware NoDrawing. Application May 26, 1937,

Serial No. 144,870

9 Claims.

The present invention relates to an improved method for producirg wax modifying agents for use in waxy lubricating oils as pour depressants and as crystallization inhibitors to be employed in the process of separating wax from mineral oils.

The invention will be understood from the. following description:

Wax. modifying. agents are now produced by condensation of parafilnic compounds having 10 long hydrocarbon chains such as paraffin wax on aromatic hydrocarbons or other cyclic compounds. The reaction is ordinarily conducted by means of Fliedel-Craft type catalysts such as aluminum chloride and it is customary to use a dilucut during the condensation step. In most cases, petroleum, naphthas, kerosenes and the like have been employed as diluents, but ethylene dichloride and propylene dichloride have also been suggested.

It has been found that the type of solvent employed has a marked effect on the yield and the potency of the wax modifying agent. It has been found to be desirable to employ solvents which are substantially non-reactive with the reactants employed under the conditions prevailing and for this reason saturated aliphatic hydrocarbons were at first preferred since they are the least expensive and are relatively unreactive. on the other hand it was found that when these materials were .0 used as the solvent medium the condensation is accompanied by the simultaneous formation of oil insoluble products. The mechanism of their formation is, as yet, obscure but such oil insoluble materials are of no value as wax modifying agents a but on the contrary are undesirable and it is obviously desirable to conduct the condensation in such a way as to avoid such formation. Various expedients have been adopted from time to time to eliminate the formation of oil insoluble materials, for example, the use of increased quantities of the catalyst in operation at more elevated temperatures have been found to decrease the formation of insoluble products but unfortunately these methods are accompanied by a decrease in the potency of the oil soluble fractions as modifying agents. One method of prominence consisted in the use of chlorinated wax of lower chlorine content, for example, below about 11%. Using a wax of this chlorine content and careful tion temperature it is possible to largely eliminate the oil insoluble material but such procedure is accompanied by a decrease in potency, due to the smaller chlorine content of the wax.

adjustment of the amount of catalyst and reac- I The present inventors have found that certain halogenated hydrocarbon solvents during the condensation leads to greatly improved results. On the one hand, these solvents give the least amountof oil insoluble waste materials and, on the other hand, if proper solvents and conditions are employed, products of a high degree of potency can be obtained, even with waxes of high halogen content, and without the production of oil insoluble products. It will be understood that theparticular solvent media do not have to be those which are completely incapable of reacting but are such that do not react readily under the conditions prevailing so that they are in effect substantially inert to the reactants. The particular solvent media which are found to best fulfill the requirements belong to two groups; first, aliphatic hydrocarbon derivatives of two or more carbon atoms in which three or more halogen atoms are attached to the same or to adjacent carbon atoms of the molecule. Among such solvents may be specifically mentioned trichlorethane, tetrachlorethane, trichlorethylene, tetrachlorethylene, penta and hexachlorethanes. Similar derivatives of propane, propylene and the butanes and butylenes may also be used, as well as the higher boiling halogenated hydrocarbons, but it is preferable to use the lower boiling derivatives of 2 to 4. carbon atoms since these may be more conveniently separated from the wax modi- 'fier and recovered. The chlorinated derivatives of these hydrocarbons are more satisfactory than the derivatives of methane because the latter are more reactive to the reactants'under the conditions employed. Saturated solvents such as tetrachlorethane are preferable to tetrachlorethylene, because under the same conditions the former produce products of greater potency. It will be understood that the chlorides are the most desirable because of their cheapness and their stability, but fluorides, bromides and iodides may, of course, be used.

The other group of solvents consist of the halogenated aromatic hydrocarbons. These compounds should contain at least two halogen atoms on the same ring but it is not of great importance whether these halogen atoms are attached to adjacent carbon atoms of the ring. It is preferred to use monocyclic aromatic hydrocarbons, that is to say derivatives of benzol, but the substituted derivatives of naphthalene can also be used. Specific examples of the most desirable compounds are dichlorhenzol, trichlorbenzol, penta or hexa chlorbenzol, di and trichlornaphthalenes.

It will be understood that other halogen atoms may be substituted for the chlorine atoms.

The wax modifying agents are prepared by reaction of at least two types of ingredients. One of these is termed a parafiinic material and among the various paraflinic materials chlorinated paraflin wax, usually containing from 10 to 15% or 20% of chlorine, is preferred. Dechlorinated wax, that is to say the olefins obtained from chlorinated wax, can also be used, but they are less reactive than the chlorine containing compound and for that reason are not so useful. Acid chlorides may also be used where there is a long hydrocarbon chain, for example, having at least 10 or 12 carbon atoms, such as stearyl or oleyl chloride. Chlorinated alcohols, ethers or esters may also be employed in the same way so long as they have relatively long hydrocarbon chains and contain an amount of chlorine comparable to the 10 to 20% of the chlorinated paraflin wax.

The second reactant is a cyclic compound which may be a hydrocarbon suchas benzol, naphthalene or anthracene, or a hydroxy aromatic such as a phenol or a naphthol, or an amine such as aniline or naphthylamine may be used. The parafiinicmaterial is used in excess of the aromatic, ordinarily to 100 parts of the chlorinated parafiinic material from 10 to 20 partsof the arcmatic are used although there may be considerable variation.

The catalytic agents employed in the condensation are in general the Friedel-Craft catalysts as mentioned above. Aluminum chloride is perhaps the best and the most generally available, but others of the same type can be used such as zinc chloride, iron chloride, aluminum bromide, boron fluoride or titanium fluoride. Ordinarily the catalyst is used in proportion of l. to 5%, or more, based on the chlorinated parafllnic material.

The reactants may be admixed in any order; for example, the chlorinated or otherwise halogenated wax and the aromatic, say naphthalene, may be mixed with the solvent and the catalyst may then be slowly added as the reaction progresses or, on the other hand, naphthalene and catalyst may be mixed with the solvent and the chlor wax added thereto slowly and the mixture kept in thorough agitation during the reaction. This latter method has marked advantages because it even permits the use of more highly chlorinated waxes, for example waxes containing 15 or even 20% of chlorine or more, and the products produced by such reactions are substantially free from oil insoluble products or, at least, the amount of insoluble product is very greatly reducedover the amount produced by mixing the reactants in any other way. It will be understood that the use of the chlorinated solvents disclosed herein is beneficial for the reaction whatever the particular method or order of adding the reagents, but is particularly beneficial when high chlorine content waxes are used and when the chlorinated wax is added to the mixture of aromatic and catalyst in the manner disclosed above.

The temperature of condensation may vary considerably, preferably from room temperature to about 200 F., the optimum temperatures depending on the particular reactants and to a lesser extent on the particular solvent medium which are used, but in general the optimum is in the range specified and well below the temperature at which the potency of the oil soluble product is found to decrease. Temperature likewise depends to some extent on the amount of catalyst used-and on the time of reaction. Ordinarily in the preferred temperature range, the time of reaction to give the most potent product should be less than about six hours, although good pour inhibitors may be obtained at longer times especially where less catalyst is used and where other factors are modified.

The reaction product is preferably finished by hydrolyzing either with acid or alkali in water or alcohol and is washed free of the catalyst sludge.

To illustrate the present invention and to set forth its advantages, the following examples are presented:

Example I Parts Chlorinated wax (11% Cl) Napthalene 13.5 Anhydrous aluminum chloride 1.4

The temperature was maintained at F. for a period of three hours and both products were finished in the same way by hydrolyzing the remaining catalyst and withdrawing the sludge.

It was found that the reaction product produced without the use of a solvent was reduced to a final content of about 2 /2% of an oil insoluble material, while there was no oil insoluble material whatever found in the reaction product made in presence of the chlorinated solvent medium.

During the course of the reaction, samples were removed from the reactor and examined for oil insoluble material present. The following comparative results were obtained:

, Formation of oil insoluble material Time 50 parts 0! N o 501- tetrachlorvcnt ethane Percent Percent 0 1 hour 25 1.5 hours 25 0 2.0 hrmn l0 0 2.5 hours 2. 5 0 3.0 hours 2. 5 0

As will be observed, there was no evidence at any time for the presence of oil insoluble material when using tetrachlorethane as solvent.

The oil products produced in each case were very similar but the product made in presence of the solvent was more potent as is shown by the fact that .0375% of the two materials respectively were added to a waxy oil having an original pour point of 30 F., the'product made without the solvent depressed the pour point to +15 F., while that made in the presence of the solvent depressed the pour point to 0 F.

Example II The same experimental procedure was used as in the previous example (No. 1). Here benzotrichloride, benzene, mono-chlor-benzene and dichlor-benrene were used respectively as solvent media. The oil soluble products were recovered as previously described The following' table illustrates the results obtained: I

Solvent alienzgt richlo- Benune Mono- Dichlor' chlor-ben- Structure Cl aene Cl l

icai reactivity oi the solvent Potency oi the oil soluble product: I ercent required to give a pourinawaxy No potency Nopotency 0.1 .06

It will be observed that as the chemical inertness of the solvent medium decreases the potency of the fluid increases and this is dependent upon the structure of the solvent.

Example III to two difierent oils, each havinga pour point of +30 F. The first of these oils, No. 1, was of a type more susceptible to reduction of pour point than No. 2. The comparison of the two products is given in the table below which shows that the product made in the presence of the chlorinated solvent produced a pour depression on an average of to 25 below that produced by an equal quantity of the material made in the presence of the kerosene:

. Madein kerosene w m" Percent added Waxy oil Waxy oil Waxy oil Waxy oil No. 1 No. 2 No. 1 No. 2

1(! Pour 5 F. 35 --e0 0 -10 +15 --10 0 +20 0 +20 Example 1v In the above example the volume of tetrachlorethane was quite large and in no case where the solvent was used was there any oil insoluble product produced. In the present example, the proportion of the ingredients was the same as before except that the amount of solvent was greatly reduced, only 15 parts being used for 100 parts of the chlorinated wax. Furthermore, the temperature of reaction was 125 F. and the reaction time about 2 /2 hours.

Under the above conditions, when no solvent was used there was a very large production of oil insoluble rubbery material which amounted to approximately 20% of the total reaction product. The yield of the purified inhibitor amounted to 60.5% based on the reactants. Where the chlorinated solvent was used there was a very small amount of insoluble material which was separated without difiiculty and a final yield of 71.3% of the depressant was obtained. The depressant in both cases was of about the same strength. This example shows that even a small amount of the particular solvent material will greatly reduce the ,product, but there was no .wasthe sameas amount of insoluble reaction product, although there was not quite enough in the present case to completely eliminate the insoluble product.

Example V The conditions of the present example closely approximated those of the prior example except that 15 parts by volume ot'ortho dichlorbenzene was used as the solvent, and the reaction period was three hours. No insoluble product was produced where this solvent was employed and the potency was such as to give a pour reduction of 5 to 10'' more on the average than could be obtained with an equal amount oi product made without the solvent. Example VI Two condensatlons were made with the same ingredients in the sameproportions, the difference between the tests being that in the first the catalyst was added to a mixture of ohlorwax and naphthalene in the presence of the solvent while in the second the chlorwax was added to the mixture of the naphthalene and catalyst in the presence of the solvent.- The ingredients were:

The temperature during the condensation was maintained at 125 F. and the time of reaction was three hours in each case. The finishing procedure was substantially the same in both instances and consistedin neutralizing the reaction mixture with caustic settling the catalyst sludge and reducing with fire and steam to a temperature of 600 F. in order to remove solvent and unreacted waxy material. v

At the end of the first experiment it was found that there was an insoluble or gummy material present to the amount of about 20% of the total such material present in the condensation product produced in the second case.

The products of the two experiments were tested in the same waxy oils-and it was found that the material made in the second test gave in all cases 5 to 10 F. greater pour reduction than could be obtained with the product oi! the first test. when these materials were added to a waxy oil having a 30 F. pour point,'it was found that .0375% of the product of the first test was re quired to produce a pour point of .0" F., while only 020% or the second material was required for the same reduction.

Emmple VII Parailin wax (122 M. P.) was chlorinated to a chlorine content of about 15%. The ingredients were:

tetrachiorethane and the temperature adjusted to 125' F. The chlorinated wax was then added to the mixture of naphthalene and AlCla. The tem-' perature was maintained at 125 F. and the reaction time was -3 hours. The finishing procedure described in Example VI, and consisted in neutralizing the. reaction mixture with caustic settling the catalyst sludge and reducing the clear oil with fire and steam to a temperature of 609 F. in order to remove solvent and unreacted waxy material.

In spite of the high chlorine content of the chlorwax used in this experiment, there was no oil insoluble material formed during the condensation reaction and the finished recovered synthetic product had a Saybolt viscosity of 8,700 seconds at 210 F. The product tested in a waxy oil was of high potency, it was found that .0375% of the product lowered the pour point from +30 F. to 5 F.

The present invention is not limited to any theory of the mechanism of the reaction nor to any reason for the improvements brought about by the use of any particular solvents, nor to any particular solvents, but only to the following claims in which it is desired to claim the invention as broadly as the art permits.

We claim:

1. In a process for producing wax modifiers in which chlorinated paraflln wax and an aromatic compound are condensed by means of aluminum chloride catalyst, the improvement which comprises mixing the aromatic compound and the catalyst with a chlorinated hydrocarbon solvent which is relatively inert under the reaction conditions, then adding a chlorinated wax to the mixture in which the chlorine content is in excess of 11% and eil'ecting the condensation.

2. Process according to claim 1 in which the solvent comprises a polychlorinated aliphatic 'hydrocarbon of two to three carbon atoms.

3. Process according to claim 1 in which the solvent is a saturated polychlorinated aliphatic hydrocarbon or two to three carbon atoms.

4. Process according to claim 1 in which the solvent is tetrachlor ethane.

5. In a process for producing wax modifiers by condensation oi chlorinated paraffin .wax and aromatic compounds with catalysts of the Friedel Craft type, the improvements comprising preparing a mixture of the aromatic compound and the catalyst in a saturated polyhalogenated hydrocarbon solvent of two to three carbon atoms, adding thereto chlorinated paraflin wax and maintaining the temperature below 200 F. to

efl'ect the reaction, then separating the catalytic material.

6. Process according to claim 5 in which the chlorine content 01' the wax is above 11%.

7. Process according to claim 5 in which the chlorine content of the wax is above 11% and'the solvent comprises a saturated polychlorinated aliphatic hydrocarbon of two to three carbon atoms.

8. Process according to claim 5 in which the solvent is tetrachlor ethane.

9. In a process for producing wax modifiers by condensation of chlorinated paraflln wax and aromatic hydrocarbons by means of aluminum chloride, the improvement comprising preparing a mixture of the aromatic hydrocarbon and aluminum chloride in tetrachlor ethane as a solvent, then adding thereto the chlorinated parafiln wax which has a chlorine content between about 13 to 20% by weight, maintaining the temperature below about 200 F. to effect the reaction, then separating the catalyst and the solvent.

EUGENE LIEBER. MARTIN M. SADLON.