Patented Nov. 22, 1949 ' 2,488,662

PATENT 2,438,662 METAL onoAigo-rnosggglfrgs , Bruce B. Farrington, James 0. .Glaytomand Johns, , T. Rutherford, Berkeley, Qallivt}, yesswignorsjto . California _ Beseaijch._~._(,3,0rl10l1él,t,ifln San-FY5111 l” dementia .cersvraiion of. liélawai ‘ '*' No Drawing. Application June. 25,1946?» Serial No.~.6'79,2,62:.¢‘ " ' ' ' 7 Claims.‘ ..(_Cl. ZGOF-AZQLN 1 _ 2 : This-invention relates to high molecular weight, wateninsomble,,mineral oil-soluble zincand cad: ., miuinsalts of acid esters-of phosphoric, acid ,. ' The polyvalent metal saltsdof iaciduesters, of ; phosphoricuacid have value'asimprovement agents, 5 for mineral lubricating; oils. . Thus, .theyare e?ec; ,. _ tiveywhen usednaloneyto increase the resistance phosphate5i to .obta-inwthe esire of suchioils-to oxidation andithey have particular u the l I " “ eféat ' “ ‘ value'ynwhenusedilin combination. with ;a poly- _ ' ' ‘ valent<=;metal..salt;of .anlalkylphenol, to inhibitlO of it‘v'is required“ 1 . - corrosionof alloy ibearingslsuch as copperelead > It'ls anobj‘e'ct of the present,y_inv,ention, to pro; , Unitedbearings' ‘States “Sewimwxampla Patent-.,,-No. ‘2,228,659 Famngton andcNeelyu et a1” , videeecleesnf.polyvalentgnetal's,‘tsbraéi'h ' 5511; “

et al.,»United States-PatentNo.x2,228,6'71. _ For convenience, these polyyalentmetal. salts T15 of acid-esters of phosphoric acidvwil-l-be frequently referred; to as polyvalent inetalphosphates- " , L pd ""2, r’ Y ~ " oi,’“ theainvention“l's‘alts‘ f ‘acidfestersiof ,to provide. Certain» of thesepolyvalentmetal phosphates, . phosp oric' "acid ,hIGIZLHIIIB , such~as the calciumandgbariurnsalts, are water- - watevrxsolii \ thaiilthe‘alkalin earthfmetalsaltsfj thatdi?icultyinsolubleto mineral a lubricatingsufficient is encountered extent; oilsa‘are orin theirpractice-sufficiently-40w; solubilitiesl Thus, I 20 wear,of these" (wheniused uoricl'ationxlasalfester'sandwhich in 1mii‘leral, aaiiei‘eaus‘éas‘ lubricating ' v‘ils itmetal-‘phosphate is- a common practice in oil ‘in to relativelylarge disperse the rpolyvalent amount, > ’ " ‘ “ of thejorderof 50% ‘ on the weight of oil-phosphate 25 solution, to produce a concentrate or stock solu- " tion; This concentrate is stored a'ndrshipp'edhto be ‘ blended with" more oil to produce a ?nished prod- ' uct containing about 0.25 to 2.0% of phosphate.~ The aforesaid calcium andbarium phosphates are 30 _‘ , di?icult to blend homogeneously ,iPFQHSY-Ich‘coQM Thes Land.,otherllobiectsoftheyinvention will”. centrates; and erenanished oilscontainiaa lesser be apparentfffioimthe ensuing’ ,éiéscr‘ipiibnianeij; amounts are prone to form emulsions 0n agitation thei'apbended claims. " " " ' ‘ ' " withacceptance, ,water, ‘testsnwhich,‘or they may include,centrituging, ,fail ‘to ,pass, stringent 9315,35 salts‘of'aci‘dWe-l'iaiefdisco esteem éifed phosphoricacidai'e that thezincandeadmium superior}; high Speed. 7 v > in thatgthey .a‘re'characterif'zedby lowlwiater-solllr,. Certain,otherjpolyvalent metaL-QhQSphatessuQh v, bility‘ijand .‘hi‘gh ToihsOIubilityQj Moreover; they dog‘ as the alminum phosphates, although more. 011; , not_,_ca_ ‘e xcessiyé ,wear'lof \workinglba?s ‘of

soluble , and, less water-soluble, ‘. cause, some .dif?: machinea ' I .lilbri‘cat'edlby .' mineral, oil's; oontaini'?gb'm combustionculty, owing engines,to wear. of such working-partsoi (ascylinder :andpiston, internal T40 them,‘The salts of the inventionarelof two types, de walls and'piston rings. v rived from the monojestersian Jtheh (ll-esters: Theabove-mentioned oil-Water ,solubilitygdi?'ie culties vcan .vbe solvediby.‘ employinguphosphoric, /0—,-R_1 O—,R1., esters of su?iciently high moleculanweight aloe-V845 :y o=13_‘_,p_R,, holswor,phenols,~but{to obviate. these di?iculties 3 ‘ \OH‘ \01; fullyfying--_- it radicalsis necessary, of excessively,by this means, :high to .useesteriv.molecula ; 11:;q Di'eateiswt weight.» These excessively highumolecular weight-m Mono-esters‘ , radicals are more expensive than.the._more,_com . - mon radicals of lowermolecular weight, contain 7. Sa1§$¢~9f;'th§;: mqno-gstersmaygbei pormalisaltsni ingu5 to 20 carbonatoms. Also, the ester‘ifyin‘g. I (Ml-‘511904) or acld salts (R1HPO4_M—R1HPQQ@=; radical functions primarily =las-an oil-solubilizingf. In theabpyertormulaaRrandRz-arehydrocarbon agent-4phosphate. and; isthe impartedbritha-zimreaeic effective-inhibiting}acacia (metaof'gthe~~.li 555 radieelsnwhich.mygbernonshrqrqcarbonsubstitueu..mncl substituted;lhowereabye M115 sine. (H .l oxygen-phosphoruszeareua sfl‘o.~tilee>.hydrochloric acid. R1 R1 The dicetyl phosphoric acid was recrystallized twice from 95% ethyl alcohol and once from ab , o t t solute alcohol. It had a melting point of 63-64.5° o=r/ “\M o=rl'~o-M-o-i>=o C. and analyzed 5.78% phosphorus (theory 5.6%). The monocetyl phosphoric acid analyzed 9.73% PM 5 t phosphorus (theory 9.64%). ILA Both acids were white crystalline materials, the are preferred, and of these the salts of the di mono-ester having a ?aky appearance and the di esters are preferred as being more oil-soluble. The ester, a granular appearance. radicals R1 and R2 contain each not less than To prepare zinc monocetyl phosphate, the po 5 carbon atoms, preferably not less than 10 car tassium salt was reacted with an equivalent bon atoms, and preferably not more than 20 car amount of zinc chloride in alcohol solution at 150° bon atoms. These radicals may be alkyl (e. g., F. over a period of 5 hours. The mixture was then amyl, hexyl, octyl, decyl, lauryl, tetradecyl, cetyl cooled to precipitate white zinc monocetyl phos and eicosyl), alkylene (e. g., octenyl, hexadece phate, which was washed with hot water to re nyl), cycloaliphatic (e. g., napthenyl, cyclohexyl move potassium chloride and unreacted zinc and methylcyclohexyl), aryl (e. g., phenyl), al chloride, as shown by the appearance of only a karyl (e. g., methylphenyl and cetyl phenyl), or faint cloud on treating 100 cc. of ?ltrate with 10 aralkyl (e. g., benzyl, phenylstearyl and cetyl cc. of 0.05 N silver nitrate. The salt was then benzyl) radicals. Saturated aliphatic and cyclo washed with hot ethyl alcohol and dried in a desic aliphatic radicals and aryl radicals substituted cator at reduced pressure. by one or more saturated aliphatic or cycloali To prepare zinc dicetyl phosphate, dicetyl phos phatic radicals are preferred. phoric acid was reacted with zinc oxide under re Mixed radicals, e. g., alkyl-cycloaliphatic and flux for 7 hours, in a solvent consisting of two alkylalk-aryl, may be used. Likewise, mixed salts parts by volume of benzene and one of ethyl a1 of mono- and di-esters may be used, c. g., mixed cohol. The desired salt was obtained as a solid zinc salts of mono-cetyl phosphoric acid and di precipitate and was washed with ethyl alcohol and cetyl phosphoric acid. 30 extracted with hot benzene. The benzene was The parent esters of the salts of the inven evaporated and the precipitated salt was dried tion can be prepared by methods :well known in under reduced pressure. Analysis: Found, per the art. Certain of the parent esters, e. g., mono cent Zn, 5.9; per cent P, 5.4. Theory, per cent and dicetyl phosphates and mono- and dichol Zn, 5.6; per cent P, 5.4. esteryl phosphates are described in the literature. Cadmium mono-cetyl phosphate was prepared Exemplary methods of preparation are provided and puri?ed in the same manner as the corre sponding zinc salt, cadmium chloride hydrate by the speci?c examples below and by Plimmer eing used in place of zinc chloride. Analysis: and Burch, Journal of the Chemical Society, 1929, Found per cent Cd, 29.1; per cent P, 6.6. Theory, pages 279-291. per cent Cd, 25.9; per cent P, 7.2. The zinc and cadmium salts can be readily pre 4.0 Cadmium dicetyl phosphate was prepared by pared from the parent esters, or from alkali metal reacting potassium dicetyl phosphate with an salts of the same, by methods well known in the equivalent amount of cadmium chloride hydrate art, as exempli?ed by the speci?c examples and in alcohol at 150° F. The solid reaction product by Plimmer and Burch, op. cit. was washed with ethyl alcohol, dried, washed with Examples of salts of the invention are: normal hot benzene, recovered from benzene solution by zinc and cadmium mono-amyl phophates, normal evaporation of the solvent and dried under re zinc ,and cadmium mono-octyl phosphates, nor duced pressure. mal zinc and cadmium mono-lauryl phosphates, normal zinc and cadmium mono-eicosyl phos EXAMPLE 2 phates, normal zinc and cadmium mono-methyl 50 Mono-tart. amylphenyl phosphoric acid and zinc cyclohexyl phosphates, normal zinc and cadmium and cadmium salts of the same mono-benzyl phosphates and normal zinc and cadmium mono-cetylphenyl phosphates; also, the p-Tert. amylphenol was reacted with an equiv corresponding normal zinc and cadmium di-amyl, alent amount of phosphorus pentoxide at 300° F. di-octyl, di-lauryl, di-eicosyl, di-methylcyclo 55 for 3 hours. The reaction product was puri?ed hexyl, di-benzyl and dicetylphenyl phosphates. by recrystallization from petroleum ether to give The following speci?c examples will serve fur white, ?aky crystals, melting point 210-214“ F. ther to illustrate the preparation and properties The zinc salt was prepared by re?uxing one molec of the salts of the invention. ular proportion of the acid with 0.68 molecular EXAMPLE 1 60 proportion of zinc oxide in a solvent consisting of Mono- and di-cetyl phosphoric acids and zinc two parts by volume of benzene and one of ethyl alcohol for six hours. The solid reaction product _ and cadmium salts of the same ' was washed with 5% aqueous acetic acid to re A mixture of mono- and dicetyl phosphoric move unreacted zinc oxide, then with ethyl alcohol acids was prepared by reacting 76 parts by weight to remove unreacted acid, and dried under re of cetyl alcohol with a mixture of 17 parts of duced pressure. phosphorus pentoxide and 7 parts of pyrophos The cadmium salt was prepared by reacting the phoric acid at 270° F. The phosphorus pentoxide potassium salt of mono-p-tert. amylphenyl phos and pyrophosphoric acid were slowly added to the phoric acid with an equivalent amount of cetyl alcohol. The reaction was complete in two cadmium chloride hydrate at 120° F. in ethyl hours. alcohol. The solid reaction product which sepa The two ‘acids were separated by dissolving in rated on cooling the mixture to room temperature hot alcohol (to 20% concentration) and cooling to was washed successively with water and ethyl al 40° F., causing precipitation of all the di-ester. cohol to remove potassium chloride, and unre The mono-ester was extracted from the alcoholic acted cadmium chloride and acid. 2,488,662 6 Properties of the various salts of the examples 241,648, ?led November 31, 1938, since issued on are given in Table I below. January 14, 1941 as United States Patent No. TABLE I 2,228,659. We claim: Melting or _ Salt Decomposi- Appearance wa?lritsolu 1. A zinc salt of an acid ester of ortho phos tion Point Y phoric acid, wherein each esterifying radical is a hydrocarbon group containing not less than 5 Zn mono-cetyl phos- (d) 642______carbon atoms. phate. Cd mono-cetyl phos- (d) 585______2. A zinc salt of an acid ester of ortho phos 10 phoric acid, wherein each esterifying radical is zpga'itein ice y 1 p h osp 11 ae_._t (m >155 — 157 __ - _ . ~ Cd dicetylphosphate... d)435______Watts“ crys Pg‘lctlcany a hydrocarbon group containing 5 to 20 carbon Zn mono-p-tert. amyl- 4) 600—612__ ‘ ' phenyl phosphate. atoms, and said salt contains a total of not less Cd mono-p-tert. amyl- (11) 668-763.. than 10 carbon atoms. phenyl phosphate. 15 3. A zinc salt of an acid ester of ortho phos d=decomposes. m=melting point. phoric acid, wherein each esterifying radical is an alkyl hydrocarbon group containing 5 to 20 These salts were all oil-soluble, the salts of carbon atoms. mono-esters being least oil-soluble and the salts of di-esters being most oil-soluble. In general, 4. A zinc salt of an acid ester of ortho phos salts of esters containing a total of at least 20 20 phoric acid, wherein each esterifying radical is carbon atoms are freely oil-soluble, those con a cycloaliphatic hydrocarbon group containing taining less than this being more sparingly oil 5 to 20 carbon atoms. soluble. 5. A zinc salt of an acid ester of ortho phos Interatomic distances of the parent esters, and phoric acid, wherein each esterifying radical is of the salts of Table I, were determined, estab 25 an alliaryl hydrocarbon group containing up to 20 lishing the identity of the salts. These inter carbon atoms. atomic distances, as determined by X-ray diffrac 6. The salts of claim 2, wherein said acid ester tion patterns, are as follows: is a mono-ester. TABLE II Interatomic distances

Mono-cetyl Dl-cetyl- Mono-p-tert. Zn Cd Zn Cd Zn_ , Cd Compound phosphoric phosphoric $333111??? mono-cetyl mono-cetyl dicetyl dicet ggrsfi’pll’lgglytl' g?g‘fgggggi acid acid acid phosphate phosphate phosphate phosphate phosphate phosphate

I

Distance in Angstrom units (I) and rela tive line intensities (II) per 0. _

Further examples of methods of preparing salts 7. The salts of claim 2, wherein said acid ester of the invention are as follows: is a di-ester. EXAMPLE 3 BRUCE B. FARRINGTON. Zinc and cadmium dicyclohexyl phophates 55 JAMES O. CLAYTON. JOHN T. RUTHERFORD. The parent acid ester is prepared by heating cyclohexanol with phosphorus pentoxide. The REFERENCES CITED salts are prepared by precipitating them from an The following references are of record in the aqueous solution of the sodium or potassium salt ?le of this patent: of the parent acid, by addition of cadmium chloride or zinc acetate. UNITED STATES PATENTS EXAMPLE 4 Number Name Date Zinc and cadmium naphthenyl phosphates 1,537,572 Zernik ______May 12, 1925 65 2,236,296 Minik et al ______Mar. 25, 1941 These are prepared by reacting naphthenyl al 2,251,798 Meidert et a1 ______Aug. 5, 1941 cohols (from reduction of naphthenic acids) with 2,346,155 Denison et al. ______Apr. 11, 1944 phosphorus pentoxide and precipitation of the . 2,360,302 Etzler et a1. ______Oct. 10, 1944 desired salts from an aqueous solution of alkali 2,409,774 Mack et al ______Oct. 22. 1946 metal salt of the parent acid ester by addition of cadmium chloride or zinc acetate. 70 OTHER REFERENCES This application is a continuation-in-part ‘of Plimmer et a1., Jour. Chemical Soc. (London), our copending application Serial No. 374,245, ?led pgs. 279-291 (1929). January 13, 1941 (now abandoned) which in turn Smith’s, “Introduction to Inorganic Chemistry,” is a continuation-in-part of application Serial N o. 75 1917, 3rd Ed., pg. 763.