US2157766A - Basic lead naphthenate - Google Patents

Description

Patented May 9, "1939 PATENT OFFICE BASIC LEAD NAPHTHENATE Kenneth E. Long, South Euclid, Ohio, assignor to The Harshaw Chemical Company, Cleveland, Ohio, a. corporation oi Ohio No Drawing.

Application October 30, 1933,

Serial No. 695,955 1 Claim. (c1. 260-435) naphthenate, etc., sold to the trade as such or under various trade names, are used in the paint, varnish, and printing ink industries as siccatives and are also used in grease making and in waterproofing compounds, etc. The usual commercial practice in preparation of these salts or soaps consists of saponification of a fatty acid or its glyceride with alkali and precipitation of the lead soap with a soluble lead salt such as the acetate or nitrate. Another method consists of combining directly a lead compound, such as litharge, with a fatty acid, in a suitable kettle or container, with the aid of heat. This reaction is carried out at a temperature from 100 C. to 250 C. Water formed by the reaction is expelled at the time of formation as water vapor or $0 steam. There is no great difference between the products made by either method with the exception that the fused products are usually darker in color and contain'some free fatty acid, as it is difficult to bring into contact, in a fusion of this 85 type, every particle of litharge with the fatty acid. By either method the metallic content is at best substantially not higher than the acid combining equivalent.

In accordance with the present invention, a

- 40 lead oxy-compound, viz.; litharge, lead hydroxide or hydrated lead oxide is intimately mixed at a temperature below 100 C. with an organic acid of the fatty acid type which is water-insoluble or at least sparingly soluble. During this mixing a reaction takes place between the acid and the lead oxid with consequent formation of water. There is a rise in temperature of the reacting mass but conditions are controlled so that the heat generated is not sumcient to expel the wa- 'ter liberated by the reaction. In contradistinc tion to the general or old practice, I have found that by my method I can introduce litharge in amounts substantially in excess of the theoretical combining ormolecular equivalent. I have found also that all of the lead so introduced is in chemical combination with the acid. As a further step, the temperature is raised to complete the reaction and drive off the water of reaction, or the water may be removed by any suitable means.

The mixing of the lead compound and acid must be positive and thorough to prevent formation of lumps of partially reacted material which are not easily incorporated if once formed. One effective way of thorough mixing is by grinding the desired mixture of acid and lead compound on ink-grinding rolls.

The following examples are illustrative of the process:

I I. 100 parts of napthcnic acid with an acid value of about 250 are mixed with about 71 parts of litharge, being thoroughly incorporated, as on ink-grinding rolls, the temperature being maintained below 100 C. Reaction sets in readily and the disappearance of the litharge soon takes place With the substantial completion of the reaction, the temperature is raised to above 100 C., and lessthan 200 C., and water formed is driven off. The product is a lead soap containing approximately 40 per cent of lead. It is a soft, gummy solid, soluble in mineral oil'naphtha, xylol, toluol, and oils such as linseed oil, etc.

II. 100parts of synthetic fatty acids made by the oxidation of petroleum hydrocarbons and having an acid value of about 360, are mixed with about 115 parts of lead oxide, PbO, with thorough incorporation, the temperature being maintained below 100 C. After thorough mixing, and progress of the reaction, the temperature may be raised to 100 C., or more, to remove the water of reaction. The product is a basic lead salt containing approximately 52 per cent of lead. It is a waxy solid soluble in xylol, toluol, also oils such as linseed oil.

III. parts-of synthetic fatty acids made by the "oxidation of petroleum hydrocarbons and having an acid value'of about 360, and about 40 parts of napthenic acid with an acid value of about 250, are mixed with about 71 parts of lead oxide, PbO, as 'afore-described, the temperature being maintained below about C., and being finally raised thereabove to drive off water of reaction. The product is a basic lead salt containing approximately .40 per cent lead. It is a soft, pasty solid, readily solublein solvents such asabove-enumerated.

IV. 100 parts of linseed oil fatty acid with an acid number of about 190, are mixed with about 71 parts of lead oxide, PbO, for instance by grinding on rolls, to a smooth paste at ordinary temperature. The temperature is then slowly raised to about 100 C., and the reaction is completed, and the temperature is then further raised to about 180 C. to drive of! water. Other organic acids can similarly be reacted, such as fatty oil acids such as oi linseed oil, flsh oil, soy bean oil, corn oil, tung oil, etc. Where dealing with acids oi rather high molecular weight, the reaction may be started particularly advantageously by the presence of a small or catalytic amount of water. For instance, by moistening the litharge or the like with water as it is mixed with the acid, or by adding a small quantity of water to the mixture. On i addition of the water, the reaction promptlmistarts. In most cases, and particularly with loweif"mnlecular weight fatty acids, reaction sets in without addition of water, and water is in fact formed in the reaction. By maintaining the tempera- 20 ture careiully below 100 C., the advantageous progress oi reaction is had, as already noted, and the temperature is to be raised ultimately, more particularly for the purpose of driving oi! water.

Other modes of applying the principle of the invention may be employed, change being made as regards the details described, provided the features stated in any of the following claims. or the equivalent of such, be employed.

I therefore particularly point out and distinctly claim as my invention:-

A lead salt product of napthenic acid containing combined lead to the extent of more than one combining equivalent weight 0! lead to each combining equivalent weight of acid but not substantially over such proportion as involved in aratio oiabout71partsoiPb0to 100partsot naphthenic acid of acid value about 250, and

being thereby basic but below maximum polible baslclty.

KENNETH E. mm. m