US2141601A - Suppressing wax in oils - Google Patents

Description

NITED STATES T OFiE sorrnassmc wax in ores Charles Edwin Greensfelder,

Shell Development Com,

Francis Suh'o ea, Calif" era to San Francisco,

Calif., a corporation of Dela No Draf Application October 22, 1934,

Serial N0. 149,499

This invention relates to a process for suppressing or inhibiting the formation of solid wax in hydrocarbon oils.

Hydrocarbon oils 5 uents often lose their separation of particles of rated wax appears either in the form of within the oil or as a more or less crystalline precipitatewhich may remain dispersed throughout the oil. Frequently, the separated wax will be found collecting on the walls of an oil container, especially at the surface of the oil, or rising to the oil surface. Such separation of wax may oclimpidity because of the solid wax. This sepacur at temperatures which are substantially above the pour point or congealing temperature of the oil, with the result that small constrictions in a lubricating system may become obstructed. 'The lack of clarity is also undesirable, because of the unattractive appearance of the oil. This is manifested bothin the formation of clouds or dispersed more or less crystalline precipitates or in the formation of surface wax.

It is one object of our invention to reduce, delay, or prevent the separation of such particles of wax by the addition of certain innocuous substances to the oil, which are hereinafter referred to as wax suppressors". Other objects of our inventionvwill be apparent from a reading of this specification.

We have found-that the addition quantities of acids effects the desired suppression of wax. As used in the present specification and claims, we use the term "saccharose as a generic term to include both monoand poly-saccharoscs. Examplesz arabinose, lyxose, glucose, fructose, su-

crose, avocado sugar and cabbage sugar. The acyl radical should preferably contain between ten and thirty-two carbon atoms and may comprise either a straight or a branched chain, and be either saturated or not. Examples: Palmitlc acid, stearlc acid, oleic aci yp ae c, acid. linoleic acid, and other aliphatic and particularly fatty acids. The saccharose should, preferably, contain between four and ten hvdrow radicals, either all or a part of which are then esterifled. We have found that best resultsare achieved when more than three and not more than ten hydroxy groups are esterifled.

Examples of saccharose esters are: tetraor pentastearyl dextrose (glucose d), tetraor pentastearyl laevulose (fructose d) pentacapryl saccbarose, octabehenyl maltose. etc.

We have found tetraand octastearyl w 30 of very small which contain waxy constita cloudy esters of saccharoses with aliphatic of about 40 F.

especially effective as wax suppressors, and it is to be understood that a preferred embodiment of our invention comprises the use of these substances.

The eifective quantity quired for inhibiting wax hydrocarbon oils varies with different suppressors and also depends upon the quantity and the nature of the wax in the oil. We have found that usually the effective amounts vary between 0.05% and 1.5% of the oil.

Such quantities of wax suppressors, as are used according to this invention, have no significant eifect upon the pour point of the oil, but have a marked efiect in preventing or retarding the separation of. wax. When used in excessive concentrations, the wax suppressors may or may not exhibit pour point reducing properties. In general, we 'found that the property of inhibiting the formation of wax is not necessarily accompanied by the property of reducing pour points of wax-containing oils. Thus, a number of known pour point reducers were tried on several oils, but failed to suppress the separation of wax at temperatures above pour points of the oils.

The wax suppressors may be added to the oil either at ordinary or at elevated temperatures. If the oil being treated contains particles of separated solid wax, it is generally desirable to warm the oil to dissolve the wax prior to its treatment.

A particular advantage of the use of the esters of our invention is that they do not appreciably darken the color of are of a light color, and are usedin quantities of the order of 1.5% or less, they usually cause no color change when used to suppress the formation of wax.

To illustrate the use and effect of our wax suppressors, the following examples are presented:

Example I Example 11' raflinate, when kept at temperatures became obscured because of the formation of a dull waxy When-0.25% ofoctastearylwasadiiedtotheoilthis and the addition of of wax suppressor re- Asimilar formation in different theoil. Since most of them effective although smaller amounts delayed the formation of this dull surface, although it did not entirely prevent it.

The addition of 1% of Paraflow (a condensa tion product of a waxy hydrocarbon material with an aromatic hydrocarbon), a known pour point reducer, had no retarding efiect onth'is precipitation of wax.

Example III Example IV A Coalinga Edeleanu rafiinate showed turbidity and cloudiness after two days storage at F. The addition of 0.1% of pentastearyl glucose to samples of the same raflinate caused them to remain clear for over days at 70 F.

Example V A Coalinga Edeleanu raflinate showed turbidity and cloudiness after two days storage at 70 1 The addition of 0.1% of octastearyl saccharose to samples of the same rafiinate caused them to remain clear for over days.

While these particular examples demonstrate the eflectiveness of stearic acid-glucose and of stearic acid-sucrose condensation products, our invention is not limited thereto, as other saturated and unsaturated monobasic aliphatic acids, having from ten to thirty-two carbon atoms, may be used.

Instead of the particular aldo-hexose and the dihexose, other keto or aldo monosaccharoses or polysaccharoses may be used.

As used in the present specification and claims, the expression suppression of wax means the prevention, reduction or retardation of the formation of solid wax in a body of 011.

Although we have heretofore disclosed that esters of monoand poly-saccharoses are suitable for suppressing wax, we have found that the ester of monoand of di-saccharose is especially useful for this purpose. A

We claim as our invention:

1. A limpid oil composition comprising a mineral oil containing wax in amount and composition normally to cause visible wax to separate from the oil in a solid state at temperatures above the pour point of the wax-containing oil, and a small quantity of pentastearyl glucose to suppress the said separation of visible wax.

2. A Jimpid oil composition comprising a mineral oil containing wax in amount and composition normally to cause visible. wax to separate a