REVIEW OF GERMAN SYNTHETIC LUBRICANTS WILLIAM A. HORNE Gulf Research & Development Company, Pittsburgh, Pa.
T h i s paper presents a brief review of the processes used by Germans to manufacture synthetic lubricating oils during World War 11. The oils were in general of high quality and were used almost exclusively for blending with natural mineral oils of lower quality or for special applications. These lubricants were of two general classes, hydrocarbons and nonhydrocarbons. The hydrocarbon class consisted of ethylene polymers, polymers prepared from mixtures of higher boiling olefins produced by the vapor phase cracking of wax or gas oil, and the condensation product of chlorinated paraffins and naphthalene. The nonhydrocarbon class consisted almost entirely of esters.
HE principal source of Cxcmns ny's lubricating oils was the relatively small supply o f indigenous crudes, from which the yield of lubiicants was 45y0 of crude charge, a remarkably high proportion. However, to obtlhin the high quality rpquired for aviation use, solvent refining methods had to be applied to selected stocks and these Upre not available in sufficient quantity to satisfy the desire for self-sufficiency. I t was therefore necessary to develop sopthetic processes based on coal to supplement the natural supply. Synthetic lubricants were manufactured to the extent of only about 1200 barrels pclr day compared to the total from all sources of approximately 17,000 barrels per day, but they accounted for about 50% of the high quality lubricants. The produrtion in thousands of barrels per year of German lubricating oils in 1942 (13, 18, 19, 21) is shown in Table I, which also indicates the method of manufacture and illustrates the high proportion of synthetic oils for aviation use. The synthetic lubricating oils manufactured were of t w o general classes, hydrocarbons and rionhydrocarbons.
T
Table 1. Source Petroleum 1.G.-Leuna Stettin-Piilitz Rhenania Ossag Ruhrchemie Rheinpreussen Brabag-Zeitz 1.G.-Leuna
German Lubricating Oils
Method of Manufacture Conventional refining E t h lene polymerization ole& polymerization Olefin polymerization Olefin poly,rnerization Condensation T a r hydro enation Ester syntfesis Total
Production 4550
90 70 60 60 15 170
Disposition Aviation Other 220 4330 90 ... 70 ... 60 .. ,. 60 ,. 15 170
3 0 -30 5045.
470
...
4575
HYDROCARBON LUBRICANTS
The hydrocarbon class consisted principally of olefin polymers prepared either from ethylene or from a mixture of higher boiling olefins. A small proportion of the hydrocarbon class was prepared by aromatic-chlorinated p a r a f i condensation. Lubricants were also made from brown coal tar (U),but these were not true synthetics. An exhaustive study of the aluminum chloride polymerization of chemically pure olefins was conducted by Zorn and co-workers ( I S , g4) of the I. G. Farbenindustrie to determine theeffect of chemical constitution of the olefin on polymer properties. Some results of this study (Table 11) show that only atraight-chain olefins with a terminal double bond produce satisfactory yields of high viscosity index (V.I.) polymers, although an is0 etructure a t the opposite end of the carbon chain may possibly have some advantage.
Yields and viscosity index are both poor when the double bond is riot in the 1-position or when there is alkyl substitution on a double bond carbon atom. Thr viscosity, viscosity index, and pour point of the polymer all increaa~a n d the ease of polymerization decrease8 as the length of the rarhon chain increases.
Table
It. Olefin Polymerization Yield,
Wt. o/o n-I-Octene 2-Methyl-1-heptene n-4-Octene 6-Methyl-1-heptene n-Octa-1-decylene
80 20 5-10 88-90 80
Viscosity, S.S.U. a t 210' F. 98
32 28 290 2 10
V.I.
100
20 -10
loo 140
Pour Point. 0 F. ~ - ( C I l i ) i & H a
...
4.70
171
...
6.65
122
...
2430
INDUSTRIAL AND ENGINEERING CHEMISTRY
PREHEATERS
0 PSI0
CRACKING CHAMBER 1616.F 2 0 0 4 0 0 MM HG
100.f
I
-
CAUSTIC
WSH
Vol. 42, No. 12
-
COOCER
CH4 AND LIGHTER
RECYCLE ETHANE SILICA GEL DRIER
LOW TEMP. FRACTIONATION
ETHYLENE, 9 5 % MIN. PURITY
Cs AND HEAVIER
ETHYLENE FROM ETHANE CRACKING
.When the autoclave was liquid full, the ethylene supply line
was closed, the pressure in the reactor was vented down b gas release ftt the top of the reactor, and the contents were read", for
processing.
The above procedure refers to the preparation of an oil of a h a 1 viscosity of 220 S.S.U. a t 210' F. (SS 906). To produce an oil of 105 S.S.U. a t 210' F. viscosity (SS 903), the polymerization temperature was controlled at 260' to 280' F. The contents of the reactor were then blown down to a batch separation vessel where, if the layers did not readily separate, a small amount of methanol was added. The mixture was then centrifuged to give a crude oil containing a small amount of catalyst complex which was removed by treatment with methanol and lime. The'neutralized oil was put through a filter press and then steam distilled a t atmospheric pressure. The aluminum chloride sludge was decomposed with an aqueous aluminum chloride solution from previous batches and yielded a highly unsaturated oil. The raw oil was treated with 6 weight yo of aluminum chloride for 3 hours a t 250' to 300' E'., separated, neutralized, and topped to produce a cylinder oil, called R oil. The yield of finished blending. stock (SS 906) was about 74 weight yo of the ethylene. There were also obtained about 7% of a light oil distillate (V-120) and 8 weight % of R oil. The properties of these products (8,IS,24) are shown in Table I V along with the lighter blending oil SS 903. A number of pqlymerization variables were of decisive importance in obtaining a satisfactory yield of quality product. The ethylene should contain no more than 5 volume yoof inert impurities such as nitrogen, methane, and ethane which do not influence the quality of the oil. Carbon dioxide, carbon monoxide, molecular oxygen, and oxygen containing organic compounds are very harmful, as indicated in Table V. Mono-olefins, diolefins, acetylene, sulfur compounds, nitrogen compounds, and water are less harmful. The aluminum chloride should not contain mare than 2.5 weight yo of unsublimable residue. Increased residues cause a
LEUNA
considerable decrease in viscosity index, as indicated in 'Table VI. Iron-free aluminum chloride yielded a high pour point polymer and it wa8 found necessary to maintain approximately 2.5 to 3.5 weight of iron in the sublimed aluminum chloride to meet the reqmre?specification (pour point of -30" to -40' F.), even though a product of somewhat lower viscosity index waa obtsmed. The effect of iron content is shown in Table VII. For highly vi& cous oils the iron content was less important. Titanium tetrachloride above 1% made the crude olymer extremely difficult to filter and therefore was maintained Below thi8 value. Table VI11 shows that the optimum concentration of aluminum chloride was about 7 to 8 weight yobased on the finished polymer.
Table
IV. Ethylene Polymerization et Leuna
Inspection Specific gravity, 6S0 F. Viscosity, S.S.U. a t 210: F. Viscosity index Pour point, O F. Flash point, O F. Neutralization No. Saponification No. Carbon residue, %
Table
R Oil
58-903
33
0.850 105
0.852-0..855
0.857
>140
115 -36
108-112 -26 to -32
100 -35 355 0.0 0.20 0.20
O O C ( C H ~ ) ~ ~ O < - ~.H-->C
Hn
e:Hs
5.1 16.7-18.5 ..
>’i20 356
120 23
..
>‘i20 -76 293
4
..
9.1 120 -94 248
(10) Hall, C. C., Craxford, S. R., and Gall, D., “Interrogation of Dr. Otto Roelen of Ruhrchemie, A.-G.,” BIOS Final Rept. 447 (1946); re-
produced on T.O.M. Reel 22G. (11) Hall, C. C., and Haensel, V., “Fischer-Tropsch ’ Plant of Ruhrchemie A-G., Sterkrade-Holten, Ruhr,” CZOS Rept. XXVII-63 (1945): Office of Technical Services, Re& PB-415; T.A.C.
Rept. SnMC-11; reproduced on T.O.M. Reel
..
*53
.. ..
..
0.806
> 6.25 23.8-27 .. 5’120 392
197.
Hall, I?. de H., “German Petroleum Industry, Hamburg District. Introductory Report,” CIOS Rept. XXXII-94 (1045): Office of Technical Services, Rept. PB-6649; reproduced on T.O.M. Reel 197. ( 1 . ) ) Holroyd, R., ed., “Report on Investigations by Fuels and Lubricants Teams a t I. G. Farbenindustrie A.-G. Works at Leuna,” CIOS Rept. XRXII-107 (1945); Bur. Mines, Information Circ. 7370 (1946); Office of Technical Services, R e p t . PB-6650: reproduced on T.O.M. Reel 197.
(12)
2436
INDUSTRIAL AND ENGINEERING CHEMISTRY
H‘orne, W.A., and Faragher, \V. F., “Interrogation of Dr. Pier and staff, I. G. Farbenindustrie A.-G., Ludwigshafen/Opgau,” FIAT Final Rep?. 426 (1945); Office of Technical Services, Rept. PB-7745 and 1367; reproduced on T.O.M. Reel 199. (15) Howes, D. A . , and Thomas, W.H., “I. G. Farbenindust,rie .I.G. Ludwigshafen, Germany (Fuels and Lubricants) ,” BIOS Final Rept. 373 (1945); Office of Technical Services, Rep‘. PB-23856. Kuhne,,P. K., “Lubricants in the Hamburg Area,” Proceedings of Technical Oil Mission Meeting, Washington, D. C., PO. 7985, December 1945. Oriel, J. A., “Oil Targets in Ruhr and Hanover Areas,” CIOS Rept. XXIII-16 (1945); Office of Technical Services, h’epf. PB-282; ‘reproduced on T.O.M. Reel 198. Schindler, H., “Lubricants, Schkapau, Leuna. and Ruhrc-hemie,” Proceedings of Technical Oil Mission Meeting, Wa’shington D. C., pp. 60-7, December 1945. Spaght, M. E.,“Manufacture and Application of Lubricants in Germany,” CIOS Rept. XXXII-68 (1945); I?.S. Navy Technical Mission in Europe, Tech. Regt. 146-45; Office of Tech~
Vol. 42, No. 12
nical Services, Rep‘. PB-6647 and 1018; reproduced on T.O.M. Reel 199. (20) Thomas, W. W.,and IVithew, J. G., “Khenania-Ossag .A&., Hamburg, Germany, Fuels and Lubricants,” B I O S Final R e p t . 1008 (1945); Office of Technical Services, R e p l . PB75862. (21) West, H. L., “Major Developments in Synthetic Lubricants and Additives in Germany,” BIOS Final R e p t . 1611; Offire of Technical Services, Rept. PB-93668; J . Inst. Petrolel~nr.34, 774-820 (1948). ( 2 2 ) Withers, J. G., and West, H . I,., “Ruhr-Chemie A. G., Ste1.krade, Holten. Interrogation of Dr. 0. Roelen,” BIOS Finn2 R e p t . 511 (1946); Ofice of Technical Services, R e p l . PB28883; reproduced on T.O.M. Reel 227. (23) Zorn, H., “Scientific Basis for Lubricating Oil Synthesis,” 1.G.Leuna (1943), Office of Technical Services, R e p t . PB-26986; reproduced on T.O.M. Reel 135. (54) Zorn, H., and co-workers, “Ethylene-Lubricating Oil Process.” 1.G.-Leuna (1943), Office of Technical Servicea, Rept. PB26984; reproduced on T.O.M. Reel 135. RECEIVED July 10, 1950.
POLYALKYLENE GLYCOL SYNTHETIC LUBRICANTS W. H. MILLETT Carbide & Carbon Chemicals Division, Union Carbide 81Carbon Corporation, Tonewanda,
N. Y.
T h e properties of polyalkylene glycol synthetic lubricants are briefly reviewed. Recent developments have included the formulation of a series of greases which incorporate the desirable features of the base liquids and the preparation of a new series of fluids having viscosity indexes ranging from 160 to 180. Data from labnratory bench wear tests, performance tests in hydraulic equipment, arid industrial and automotive gear installations show that the polyalkylene glycol lubricants are characterized by excellent wear resistance.
PPROXIMATlSLY four years ago, the coiiiinercial availability of a new series of synthetic lubricants was first
A
announced (7). Thest: fluids have been identified chemically BS polyalkylene glycols and t,tieir derivatives. They are niwketed under the trade-mark Ucon, :tnd certain products 1i:bve betxi marketed tts a motor oil under the brand name Prestone. During the past 4 years these synthet,ic: fluids have aroused the interest of chemists and engineers becaust. of their unique properties anct favorahle performance chwtraotcyisttics. They have been widely utilized industrially (9, f4) in surli diverse applicatious :LShydraulic fluids, textile fiber and rubber processing lut)iic;tiits, coinpressor lubricants, heat transfer niedia, high temperature Iubri~;miLs for glass manufacturing machinery and kiln car wheels ( 2 ) ,hot, running bearings, and oven chains; as low temperature lubricants for hearings and electric.motors, as defoamers itrid emulsion breakers, and as components of model engine fuels, hair dressinin, leather dressings, gasoline antifreeze mistures, and printing inks. Special formulations iiicorporating tho polyglycol-type fluids are being widely used as automotive hydr:mlic brake fluids ( 5 , 15) and as aqueous, uonflammable :tircrttft and industrial hydraulic fluids (6, 11, 12). The performance characteristics of cert,ain of these synthetic lubricants in automotive internal combustion ringinw have also been studied ext,ensively ( 7 , 18).
PROPERTIES OF P O L Y A L K Y L E N E G L Y C O L FLUIDS
At present three seritts of polyal kylene glycol lubricant,s are \wing produced commercidly : thct LH series which is witctririso1ut)le and the 50-HB and T3II sories which are water-soluble. A uwv fourth series, 13, in presciitcd here. .The LB, 50-IIB, and 751% series include .st:tndnrd lubricants having viscositics from 55 to 90,000 S. I-.S. at 100 F. Their viscosity-temperatun? ohar:icteristics arc good ( 1O ) , viscosity indexes of most’ products rangiiig from 135 to 155, :tlthough certain fluids are available \vitli values as high as 180. Thc+~st>:tble,viscous pour points are significaritly lower than :&rethrtnc: of most mineral oils of comptiralile viscosity. .4lthough tlivg c:winot be considered nonflaminable, they have heen found to be inherently more resistant t o certaiti typos of flame prop:tg&oii than hydrocarbons ( 1 1, 16). They :ire widely used in the presence of rubber because ol the 1ic:gligii)l.v low solverit or swelling effect they exert toward most types of natural and synt,hetic rubbrr. IJnder degenerative oxidizing cdriditions, they trtntl to hrc:tk d o w n into volatile decomposition products rat,her th:tii to crnck :tiid polymerize or resinify :ts is the case with iiiinc~:il’oils. It is prohably because of this l i t t h characteristic that, thcw: flrLids have been found to have unusual ~.csista~ice to the foriii;ition of sludge gum, varnish, and c:t,rl,o11.
