US3686239A - Process for the preparation of sulfohydrocarbon-di-yl neocarboxylates - Google Patents

Abstract

IN ACCORDANCE WITH CERTAIN OF ITS ASPECTS, THIS INVENTION RELATES TO A NOVEL PROCESS AND TO NOVEL COMPOSITIONS USEFUL FOR ELECTRODEPOSITING NICKEL, SAID COMPOSITIONS COMPRISING COMPOUNDS HAVING THE FORMULA:

R1-C(-R2)(-R3)-COO-R-SO3-M

WHEREIN R1, R2 AND R3 ARE EACH ALKYL GROUPS, R IS A HYDROCARBON-DI-YL GROUP CONTAINING AT LEAST 2 CARBON ATOMS, AND M IS A CATION.

Description

U.S. Cl. 260400 3 Claims ABSTRACT OF THE DISCLOSURE In accordance with certain of its aspects, this invention relates to a novel process and to novel compositions useful for electrodepositing nickel, said compositions comprising compounds having the formula:

wherein R R and R are each alkyl groups, R is a hydrocarbon-di-yl group containing at least 2 carbon atoms, and M is a cation.

This invention relates to the electrodeposition of nickel. tion Ser. No. 468,149 filed June 29, 1965, now Pat. No. 3,390,062.

This invention relates to the' electrodeposition of nickel. More particularly this invention relates to compositions which may be used as surfactants and in electrodeposition of nickel.

As is well known to those skilled-in-the-art, the electrodeposition of nickel may commonly be carried out from nickel plating solutions or baths containing at least one nickel compound providing nickel ions together with various additives including primary brighteners, secondary brighteners, secondary auxiliary brighteners, etc. These solutions typically may contain surfactants, detergents, dispersants, etc. to depress the surface tension and reduce pitting at the cathode surface.

It is an object of this invention to provide a novel process for electrodeposition of nickel. It is a further object of this invention to provide a novel nickel plating bath containing a novel surfactant which is highly resistant to hydrolysis, highly water soluble, and which will reduce surface tension.

It is an object of this invention to provide novel sulfohydrocarbon-di-yl neocarboxylate compositions which may be employed as surfactants in metal finishing, metal electroplating, pesticides, and in heavy duty cleaning processes. These surfactants may be highly water soluble, highly resistant to alkaline or acid hydrolysis, and

when present even in small amounts may greatly reduce surface tension as e.g. in nickel electroplating baths.

Other objects and advantages will be obvious to those skilled-in-the-art after inspection of the following description.

In accordance with certain of its aspects, the novel process of this invention for electrodepositing nickel onto a basis metal may comprise passing current from an anode to a basis metal cathode through an aqueous acidic nickel United St e Patent "Ice plating solution containing at least one nickel compound providing nickel ions for electrodepositing nickel and containing as a surfactant a compound which provides sulfohydrocarbon-di-yl neocarboxylate anion wherein R R and R are alkyl groups and R is a hydrocarbon di-yl group containing at least two carbon atoms.

A neocarboxylate is derived from a neocarboxylic acid i.e. an acid having a tertiary carbon atom a to a carboxylic group, viz having a carbon atom connected directly to four other carbon atoms, one of which is a component of a carboxylic group.

Nickel plating may be carried out in accordance with this invention from baths containing at least one nickel compound providing nickel ions for electrodepositing nickel. Typically this compound may be a nickel salt such as nickel sulfate, nickel chloride, nickel sulfamate, nickel fluoborate etc.; and the bath employed may be 3 Watts bath, a high chloride bath, a sulfamate bath, a sulfamate-chloride bath, etc. A preferred bath may be a Watts bath, having an electrometric pH of 4.0, and containing, in aqueous solution, 300 g./l. nickel sulfate, 60 g./l. nickel chloride, and 45 g./l. boric acid.

These baths may be used with the compounds of the invention without brightening additives as when employed in techniques such as nickel electroforming, decorative plating, or building up of worn parts or may contain other ingredients to obtain bright, leveled, and ductile deposits. These ingredients may include primary brighteners as are known in the art, e.g. acetylenic, N-heterocyclic, active sulfur, etc., primary brighteners, secondary brighteners as are known in the art, e.g. aryl sulfonates, aryl sulfonamides, etc.; and secondary auxiliary brighteners as are known in the art, e.g. sodium allyl sulfonate, sodium 3-chloro-2-butene sulfonate-l, etc. In duplex nickel plating processes in which corrosion effects are minimized, the bath-compatible surfactants of this invention may be used in semi-bright as well as bright nickel plating baths.

Plating may be effected by passing direct current from the anode to the cathode through the aqueous solution containing the nickel ions and the novel surfactant. Typically, in certain nickel plating baths, the solution or bath may be maintained at temperature of 40 C.- 0, say 55 C. Agitation may be provided by air or mechanically as by a moving cathode bar. Current density during electroplating may be 2-10, say 5 amperes per square decimeter (a.s.d.). Plating may typically be carried out for 10-60, say 30 minutes.

The anode which may be used may be a soluble anode, typically nickel, or an insoluble anode, typically lead. The cathode may included basis metals such as ferrous metals, as steel, copper, including alloys thereof as brass or bronze, zinc, etc. Typically, it may bear a first plate of copper and a plate of semi-bright nickel.

Small amounts of the additives may reduce the surface tension to about 40 dynes/cm. which is suflicient to prevent pitting of the plated metal. As little as 0.125 g./l. of the additive effectively reduces pitting. The preferred amount of surfactant additive may be 0.125-2 g./l., say 0.75 g./l.

The novel surfactant obtained, according to certain aspects of this invention, may be a sulfohydrocarbon-diyl neocarboxylate compound having the formula wherein R R and R are each alkyl groups; R-is a hydrocarbon-di-yl group containing at least 2 carbon atoms; and M is a cation. Typically M may be hydrogen, an alkali metal, preferably sodium or potassium, a polyvalent metal such as an alkaline earth metal, preferably calcium or strontium, nickel, cobalt and copper, and ammonium including substituted and unsubstituted ammonium. Preferred substituted ammonium cation may include a tertiary ammonium cation, e.g. triethanolammonium, trilaurylammonium, trimethanolammonium, methanoldiethanolammonium, etc. For use in baths from which metals are electrodeposited, the compound is bathcompatible and provides the novel anion. In this aspect of the invention, M may preferably be alkali metal, e.g. sodium or potassium or the same as the metal being electrodeposited. These include nickel, cobalt, copper, etc.

It is apparent that when M is polyvalent, the valences thereof may be satisfied by linkage to more than one sulfohydrocarbon-di-yl neocarboxylate group. Thus when M is a divalent metal, e.g., nickel, the corresponding bis salts may be formed.

Typical preferred specific sulfohydrocarbon-di-yl neocarboxylates which may be used in the practice of this invention may include:

TABLE I Acid 3-sulfopropylpivalate Sodium 3-sulfopropylpivalate Potassium 3-sulfopropylpivalate Triethanolammonium 3-sulfopropylpivalate Nickel bis-(3-sulfopropylpivalate) Potassium 3-sulfopropyl neo-nonanoate Sodium 3-sulfopropyl neo-nonanoate Potassium 2-su1fopropyl neo-nonanoate Potassium 3-sulfobutyl neo-nonauoate Triethanolammonium 3-sulfopropyl neo-nonanoate Triethanolammonium 2-sulfopropyl neo-nonanoate Nickel bis-(3-sulfopropyl neo-decanoate) Potassium 3-sulfopropyl neo-pentadecanoate Potassium 3-sulfopropyl neo-heptadecanoate Triethanolammonium 3-sulfopropyl neo-nonadecanoate Triethanolammonium 4-sulfobutylpivalate Potassium 4-sulfobutyl neo-nonanoate Potassium 3-sulfopropyl neo-heptanoate Potassium 3-sulfopropyl neo-tridecanoate It will be apparent that the cations employed in the table may be replaced by other cations.

Pivalates are derived from pivalic acid which has the structure Other typical neocarboxylic acids from which neocarboxylate esters of this invention may be prepared may be those commercially available as Enjay neocarboxylic acids and as Versatic acid esters typically derived from mixtures of higher neocarboxylic acids containing more than 5 and typically 6-19 carbon atoms, sold under the trademark Versatic.

A commercial mixture of 7 carbon neocarboxylic acids (neo-heptanoic acids), may contain neocarboxylic acids having the structure RI R"-('JOOOH wherein R, R", and R' are alkyl groups having a total of 5 carbon atoms, and may be available under the designation Enjay neo-heptanoic acid. These acids include Over of the mixture may be the 2,2-dimethylpentanoic acid and the remainder may be the 2-ethyl-2- methylbutanoic acid. This commercially available acid is a liquid and has an acid value of 431.

Another commercial mixture of 9 carbon neocarboxylic acids (neo-nonanoic acids), wherein R in the general formula R! R-( 3--C OOH is methyl R and R' are alkyl groups having a total of 6- carbon atoms, may be available under the designation Versatic 9 acid. These acids include This commercially available acid is a liquid which is immiscible in water and has an acid value of 343.

Another commercially available acid which is a mixture of 9-11 carbon acidsv (neo-nonanoic acid, neodecanoic acid, and neo-undecanoic acid) may contain neocarboxylic acids having the structure:

wherein R and R" may be alkyl groups having a total of 6-8 carbon atoms. This acid may be prepared by the reaction of olefins, water, and carbon monoxide in the presence of a strong acid catalyst. The commercialy Versatic 911 acid may contain approximately 90% neocarboxylic acid. This commercially available acid is a liquid which is immscible in water and has an acid value of 300. It further has a refractive index n of 1.447 and solidifies below 30 C.

Another commercially available acid which is a mixture of 10 carbon neocarboxylic acids (neo-decanoic acids) may contain neocarboxylic acids having the structure,

wherein R, R", and R are alkyl groups having a total of 8 carbon atoms, and may be available under the designation Enjay neo-decanoic acid. The neo-carboxylic acid content of this product may be greater than Of the neo-carboxylic acids present, about 25% i5% cointain methyl groups in the R and R" positions, about 60%: 10% contain one methyl group in but one of the R, R", and R'" positions, and about 15%il0% contain alkyl groups containing at least two carbon atoms in the R, R", and R' positions.

Another commerically available acid which is a mixture of 13 carbon neocarboxylic acids (neo-tridecanoic acids) may contain neocarboxylic acids having the structure:

III

wherein R, R", and R are alkyl groups having a total of 11 carbon atoms, and may be commercially available under the designation Enjay neo-tridecanoic acid. The neo-tridecanoic acid content of this product may be greater than 95%. A portion of the impurities may be homologous neo-carboxylic acids. The proportion of acids containing one or two methyl groups in the positions attached to the carbon atom alpha to the carboxylic group of Enjay neo-tridecanoic acid is similar to the proportion obtained in Enjay neo-decanoic acid.

Another commercially available acid which is a mixture of 15-19 carbon acids (neo-pentanoic acid, neohexadecanoic acid, neo-heptadecanoic acid, neo-octadecanoic acid, and neo-nonadecanoic acid) may contain neocarboxylic acids having the structure wherein R and R" are alkyl groups having a total of 12-16 carbon atoms. This acid may be prepared in a similar manner to Versatic 911 acid. The commercial Versatic 1519 acid is a liquid which is immiscible with water and has an acid value of 207.

The neocarboxylic acid mixtures, as obtained commercially, particularly the acid mixtures include acids having at least 4 carbon atoms, may also contain a proportion of other materials including secondary acids and a hydrocarbon-paraffinic oil commonly known as neutral oil. The ester compositions may, if desired, be separated from the neutral oil by ether extraction. When it is desired to employ the esters as wetting agents in nickel plating baths, the neutral oil may preferably be removed.

The most preferred esters which may be used in the practice of this invention may typically be the 3-sulfopropylpivalates and the 3-sulfopropyl neo-nonanoate.

The novel compounds of this invention may, in accordance with certain of its aspects, be prepared by reacting in a solvent dispersion, (l) neocarboxylic acid, (2) an alkaline compounds which provides the cation M and (3) a hydrocarbon sultone.

The reaction preferably is carried out in a solvent in which the reactants are dispersible, i.e. suspendible or soluble, and is most preferably carried out in a solvent in which the compound containing the M cation is soluble. Such solvents may typically include organic solvents such as alcohols, etc. An especially preferred solvent for the reaction is methanol.

The neocarboxylic acid employed may preferably be one of those mentioned supra, e.g. pivalic acid and higher neocarboxylic acids such as those containing more than 5 carbon atoms and typically 6-19 carbon atoms. Especially preferred neocarboxylic acids may include pivalic acid and mixtures of 9-ll carbon neocarboxylic acids.

The alkaline compound which provides the cation M may be indicated as MX in which X is an anion typically hydroxide. M may typically be ammonium or alkali metal, e.g. sodium, potassium, lithium, etc. When ammonium is employed, it may be substituted or unsubstituted. Preferred substituted cations may include triethyl ammonium, trimethyl ammonium, trilauryl ammonium, trimethanol ammonium, methanol diethanol ammonium, etc. Com monly the cations may be present as MOH, e.g. sodium hydroxide, potassium hydroxide, lithium hydroxide,

etc. and most preferably sodium or potassium hydroxide, particularly when it is intended to employ the surfactants in metal plating baths.

When preparing the salts of the sulfohydrocarbon-diyl neocarboxylates where M is not ammonium or alkali metal and particularly where M is a polyvalent, it may be desirable to prepare the desired M salt by first preparing the alkali metal sulfonate salt and then passing its water solution through a cation exchange resin on the hydrogen cycle to obtain the free sulfonic acid in the eluate. The eluate may then be neutralized with the oxide, hydroxide, carbonate, etc. of the metal desired, e.g. nickel or cobalt to form the desired metal salt of the sulfonic acid.

The sultones which may be employed to prepare the novel compounds of this invention may include those containing a carbon-oxygen-sulfur-carbon linkage in a ring, the hexavalent sulfur atom being further bonded to two additional oxygen atoms. Typically such sultones may have the formula R so 2 0 wherein R is a hydrocarbon-di-yl group containing at least two carbon atoms. The sultone which may preferably be used may contain 2-8 carbon atoms. The most preferred sultone may be 1,3-propane sultone,

uni-0H3 (1H2 SOz although sultones such as 1,1,3-trimethyl-l,3-propane sultone CHa oH--c-oHi HaC-CH SOz 1,4-butane sultone,

0H, om \CH2 (3H2 and 1,3-butane sultone,

CH2CHCH (5H2 also may produce highly useful additives. The longer chain alkane sultones such as pentane sultones and octane sultones or other sultones containing several carbon atoms, such as tolyl sultones C Ha I o \SIO2 may also be used to produce additives within the scope of the invention.

The process may preferably be carried out by dispersing the acid and the alkaline compound in an alcohol and slowly adding the hydrocarbon sultone, preferably in the same solvent, to the system. It is also preferred that the addition be made while the system is at reflux, although the temperature may also be raised to reflux after the addition is complete in order to avoid some exothermic effects.

In a preferred embodiment of the invention the neocarboxylic acid may be reacted under reflux in solvent, preferably methanol with the compound MOH, preferably potassium hydroxide and the sultone preferably 1,3- propane sultone, in about a 1:121 molar ratio. In practice it may be preferable to use MOH and the sultone in slight excess (up to about of the theoretical molar ratio to assure more complete reaction. It also may be desirable to keep the reaction mixture alkaline by further addition of MOH during the reflux period, using litmus or other suitable indicator of alkalinity. The slight excess of MOH and sultone may result in formation of a hydroxy sulfonate which need not be separated from the desired product.

To obtain as high a yield of product as possible it may be preferably to evolve the solvent by heating under reduced pressure. The essentially solvent-free residue may then be separated from neutral oil in the manner heretofore indicated if desired.

The product may also be separated from the solvent by the spray drying technique wherein the reaction mix ture is sprayed into contact with hot air or a fluidized bed of the reaction product as independently produced to evolve solvent and give a residue of dried product.

During the process the reactants may react as follows:

1?: R2-(|7-C00R-SO3M H2O a The product of this reaction, typically that formed from pivalic acid, potassium hydroxide, and 1,3-propane sultone, may be readily recovered in high yield. In this product, it is apparent that the R group in the general formula i.e. the basic hydrocarbon-di-yl chain (containing at least 2 carbon atoms, and preferably 28 carbon atoms) in the structure of the molecules of the sulfohydrocarbondi-yl neocarboxylate, is derived from the sultone by opening of the ring. Illustrative alk-di-yl and substituted alkdi-yl R groups employed as aforesaid are ethane-1,2-diyl; propane-1,2-yl; propane-1,3-di-yl; butane-1,4-di-yl; pentane-1,5-di-yl; hexene-1,6 di-yl; heptane-l,7-di-y1; cotane-1,8-di-yl; etc. Alkyl-aryl groups include pentane- 1,5-di-yl; o-benzyl; m-benzyl; p-benzyl; etc. Arylene groups include phenylene; 1-methyl-2,3-phenylene, 1- methyl-2,4-phenylene; 1-methyl-2,5-phenylene; etc.

The novel compounds of this invention may also be prepared by reacting a neocarboxylic acid with a hydroxy sulfonate, HO-R403M, by the following reaction:

wherein R, R R R and M are as previously defined. For example HO-RSO M may be sodium isethionate, HO(CH S0" Na; sodium hydroxypropane sulfonate, HO(CH SO Na; etc.

In a typical example of this reaction, equimolar amounts of pivalic acid and sodium isethionate may be heated in solvent medium, typically water, preferably in the presence of a catalytic amount of a catalyst, typical 1y boric acid, and then heated further after volatilization of the solvent to say 200 C., thereby obtaining sodium 3-sulfoethylpivalate.

This invention may be further illustrated by the following examples which disclose synthesis of typical products of this invention and the use of such products as in the depression of surface tension in nickel plating baths. All parts are by weight unless otherwise indicated.

Example 1 A commercial mixture of neo-nonanoic acid, neodecanoic acid, and neo-undecanoic acid (sold under the designation Versatic 911 acid) may be reacted with 1,3- propane sultone and potassium hydroxide in methanol, to produce the potassium 3-sulfopropyl acid ester as follows:

26 parts of potassium hydroxide dissolved in 88 parts of methanol may be slowly added to 50 parts of the acid, while agitated. 61 parts of 1,3-propane sultone dissolved in 20 parts of methanol may then be slowly added over a period of 15 minutes and the reaction mixture refluxed for five hours and allowed to cool, thereby resulting in a solid mass of a gel-like product. This may be heated slowly to redissolve, and placed on a steam bath under vacuum to volatilize methanol. The potassium salt of the 3- sulfopropyl acid ester may then be dissolved in Water, diluted to 500 parts and extracted with two 70-part portions of ether to recover and separate an ether solution of neutral oil.

The aqueous layer may then be evaporated down to 250 parts, and diluted again to 500 parts with water producing a clear light yellow solution of potassium 3-sulfopropyl acid ester. The ester may be obtained in substantially stoichiometric amount.

Example 2 A solution of 64 parts of 1,3-propane sultone (0.53 mol) in 400 parts of methanol may be added dropwise to parts of methanol containing 51 parts of pivalic acid (0.50 mol) and 20 parts of sodium hydroxide (0.53 mol). The reaction mixture may be agitated and held at reflux, over a period of about 6.5 hours. The reaction mixture may then be allowed to cool and the methanol then removed under vacuum. The residue may be diluted to 500 parts with Water and impurities removed therefrom by extracting twice with ether. The remaining clear, colorless aqueous solution contains sodium 3-sulfopropylpivalate which is obtained in substantially stoichiometric amounts.

Example 3 78 parts of 1,3-propane sultone in 20 parts methanol may be added over a period of 15 minutes to a refluxing reaction mixture containing 86 parts of triethanolamine, parts of a commercial mixture of neo-nonanoic acid, neo-decanoic acid, and neo-undecanoic acid (sold under the designation Versatic 911 acid), and parts of methanol. The addition may be added over 15 minutes, after which the reaction mixture may be refluxed for 2 hours. The reaction mixture may be heated to drive off methanol, leaving a residue of 275 parts containing the triethanolamine salt of the 3-sulfopropy1 acid ester as a mobile amber liquid in substantially stoichiometric amount.

Example 4 50 parts of the potassium salt of the 3-sulfopropyl acid ester obtained in Example 1 may be dissolved in 100 parts of methanol to which 18.7 parts of concentrated hydrochloric acid may then be added. The solution may be heated and agitated for an hour after which time a white precipitate forms inmmediately on addition of hydrochlorie acid to produce substantially stoichiometric amount of the 3-sulfopr0pyl neocarboxylic acid.

Example 5 50 parts of a commercially available neo-nonanoic acid (sold under the designation Versatic 9 acid) may be dissolved in potassium hydroxide. 61 parts of propane sultone in 32 parts of methanol may be slowly added over a period of 5 minutes to a refluxing mixture of the acid in methanol. Refluxing may be continued for about 4 hours and the methanol then removed. The residue potassium 3- sulfopropyl neo-nonanoate, a thick viscous liquid obtained in substantially stoichiometric amount, may be dissolved in water and diluted to yield a slightly brownish-yellow liquid.

Example 6 61 parts of propane sultone dissolved in 40 parts of methanol may be added dropwise over a period of twenty minutes to a refluxing commercial mixture of neo-pentadecanoic acid, neo-hexadecanoic acid, neo-heptadecanoic acid, neo-nonadecanoic acid (sold under the designation Versatic 1519 acid) in 80 parts of methanol containing 26 parts of potassium hydroxide. Reflux may be continued for three hours after the completion of the addition of the propane sultone. The reaction mixture may then be heated to volatilize alcohol. 162 parts of a gel-like product may be produced. This may be dissolved in 2000 parts of water. Neutral oil may be extracted from 100 parts of the foregoing solution with ether leaving a clear water layer. The ether layer may be evaporated to leave. a residue of 0.8 grams of neutral oil. The remaining aqueous layer is a clear, colorless solution containing substantially stoichiometric amount of potassium 3-sulfopropyl neocarboxylic acid ester.

Example 7 To a standard Hull Cell containing 267 ml. of a Wattsbath containing 300 g./l. of nickel sulfate, 60 g./l. of nickel chloride, 45 g./l. of boric acid, and having a pH of 4.0 (electrometric), 0.06 gram of the potassium 3-sulfopropyl neocarboxylate prepared by the process of Example 1 may be added. The surface tension of the electrolyte, as determined by a stalagmometer, may be observed to be depressed from 76 dynes/cm. of 58 dynes/cm. A highly polished brass cathode sheet may be plated for 10 minutes at 2 amps at a temperature of 54 C. The plated cathode may be observed to have a uniform white nickel plate which is substantially pit-free and striation-free over the conventional nickel plating range of to 12 amperes per square decimeter.

Example 8 The solution of Example 7 may be modified by adding brightening agents as follows: 0.02 g./l. of N-2,3-di-chloropropenyl-pyridinium chloride; 2 g./l. of the sodium salt of saccharin and 3.2 g./l. of sodium 3-chlorobutene-sulfonate-l. Plating a standard cathode under the same conditions as those of Example 7 results in a brilliant, substantially pit-free, and striation-free, ductile nickel deposit. No indication of any incompatibility of the potassium 3-sulfopropyl neo-carboxylate with any of the other bath components may be observed.

Example 9 The solution of Example 7 may be modified by adding, as brightening agents, 4 mg./l. of thiodipropionitrile and 4 g./l. of 4,4-di-(N-sulfonylbenzene-sulfonamido) biphenyl. Plating a similar cathode under the same conditions as those of Example 7 results in a substantially pit-free and striation-free, bright, ductile deposit. No indication of any incompatibility of the bath components may be observed.

Example 10 The depression of the surface tension of a nickel plat- Grams of sodium 3-su1fopropyl Surface tension in neocarboxylate per liter: dynes/cm. (a) 0.00 76 (b) 0.125 63 (c) 0.25 58 (d) 0.50 52 (e) 0.75 42 (f) 1.00 -1 35 (g) 1.25 33 Pitting may be observed to be vritually eliminated on the cathode during nickel plating tests when at least 0.75 gram of the additive is present in the above nickel plating bath.

As many embodiments of this invention may be made without departing from the spirit and scope thereof, it is to be understood that the invention includes all such modifications and variations as come within the scope of the appended claims.

I claim:

G. The process for preparing sulfohydrocarbon-di-yl neocarboxylates which comprises mixing in a solvent as a reaction medium(l) a compound having the formula MOH wherein M is a cation, (2) neocarboxylic acid having the formula wherein R R and R are each alkyl groups and (3) a hydrocarbon sultone containing a hydrocarbon chain of at least 2 carbon atoms, and heating said reaction medium.

2. The process for preparing sulfohydrocarbon-di-yl neocarboxylates as claimed in claim 1 wherein said solvant is methanol.

3. The process for preparing sulfohydrocarbon-di-yl neocarboxylates as claimed in claim 1 wherein said compound having the formula MOH and said sultone are present in slight excess with respect to said neocarboxylic acids.

References Cited UNITED STATES PATENTS 3,067,221 12/1962 Buesink et a1. 260-400 3,420,858 1/ 1969 McCrimlisk 260-400 ELBERT L. ROBERTS, Primary Examiner US. Cl. X.R.