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This document contains information affecting the National Defense of the United States within the meaning of the Espionage Act, 50 U.S.C., 31 and 32, as amended.  Its transmission or the revelation of its contents in any manner to an unauthorized person is prohibited by law.

T.A.C. Report LMC-1

(T.O.M. Report No. 13)

Synthetic Lubricating Oils From Tetrahydrofuran, Additive for Break-In Oil and Recoil Fluid at I.G. Farbenindustrie - Leverkusen, Germany

Reported by

W.F. Faragher, U.S.A.
C. C. Chaffee, U.S.A.
D. A. Howes,  U.S.A.
H. Schindler,    U.S.A.

Information Supplied by the United States Government Technical Oil Mission

Submitted for Distribution by the Petroleum Administration for War

to the Technical Advisory Committee (A Subcommittee for the Technical Committee)

of the Petroleum Industry War Council

Report on I.G. Farbenindustrie - Leverkusen, Germany

Reported by

on behalf of the British Ministry of Fuel and Power and U.S. Technical Industrial Intelligence Committee

C.I.O.S.

Target No. 30/Opportunity
Fuels and Lubricants

July 25, 1945

Combined Intelligence Objectives Sub-Committee
G-2 Division, SHAEF (Rear), APO 413.

Table of Contents

Personnel of Team

Dr. W. F. Faragher )     U.S. Petroleum Administration for War
Dr. Hans Schindler )

Capt. C. C. Chaffee      U. S. Ordnance Department

Dr. D. A. Howes           British Ministry of Fuel and Power

Recoil Fluid

Summary

The mixture of triglycol, ethylene glycol and water used regularly by the German Army as recoil fluid was found unsuitable in the winter campaign in Russia.  The addition of a sulfonamide of low molecular weight eliminated the difficulty since, in this way, it was possible to obtain a recoil fluid of not too high viscosity at low temperatures and still to maintain the high specific gravity necessary for satisfactory brake action.

Information was obtain by interrogating Dr. Detlef Delfs, on July 5 and 6, 1945.

Details of Formulation

The composition of the German recoil fluids in given in the following tables.  The addition of K₂F₂ prevents corrosion of light-metal alloys, whereas mercaptobeno-thiazol was added for rust prevention.  The mixture of sodium and potassium salts of phenylglycine served as anti-oxidant.  The code name "methanamid" is used at Leverkusen for the monomethylamide of methane-sulfonic acid, CH₃SO₂NHCH₃, whereas "Sulfoathan" stands for the methyl-hydroxyethylamide of methane-sulfonic acid, 

The figures in the table give the composition as per cent by weight.

Manufacture of sulfonamide.

The manufacture of "Methanamid" and "Sulfoathan" is carried out according to the following scheme:  

W.F. Faragher, U.S.A.
C. C. Chaffee, U.S.A.
D. A. Howes,  U.S.A.
H. Schindler,    U.S.A.

Synthetic Lubricating Oils From Tetrahydrofuran

Summary.

Synthetic oils of good viscosity index but poor thermal stability have been prepared at Leverkusen by copolymerization of tetrahydrofuran and ethylene oxide in the presence of FeCl₃ and SOCl₂.  Engine tests with an oil of a viscosity of about 83 SUS at 210º F. resulted in ring sticking after short running time and indicated that the piston was not properly lubricated, probably because of decomposition of the lubricant.  The synthetic product is not miscible with petroleum oil.  It has been used as gear oil and for the lubrication of machinery operating at temperatures below 280º C.  Production of the material was irregular and on a small scale (maximum 1-2 tons a month).

Information on the subject was obtained by interrogation of Dr. Otto Bohme, manager of the dyestuff intermediates department, and especially Dr. Detlef Delfs, head of the research laboratory of the intermediates department, on July 5 and 6, 1945.

Theory of Polymerization of Tetrahydrofuran.

The ability of tetrahydrofuran to polymerize in the presence of oxonium salts was discovered by h. Meerwein and his collaborators, and the possibilities of the reaction were investigated by the I.G. at Leverkusen.  A comprehensive patent application by the I.G. covering the present state of the chemistry of this field has been obtained.

The oxonium salt which serves as catalyst is formed directly in the reaction mixture from tetrahydrofuran, SOCl₂ and FeCl₃ leads to the formation of a tertiary oxonium salt of the following structure:

This compound reacts with tetrahydrofuran according to the following scheme:

To eliminate the chorine present in the molecule, the polymerizate is reacted with methanol to give the final product that has the following structure:

CH₃O - [(CH₂)₄O] _n - CH₂CH₂CH₂CH₂OCH₃

The above compound is a solid and is not suitable as a lubricant.  In order to obtain liquid products, copolymerization with ethylene oxide or a similar compound is necessary.  Copolymerization with propylene oxide, e.g., leads to synthetic oils with a pourpoint of -60º C.  Instead of methanol, it is of course possible to use other compounds; e.g., phenol.

Manufacturing Details.

Two grades of oil, M620, about 83 SUS at 210º F., and M586, about 256 at 210º F., have been prepared on the semi-plant scale.  The manufacture of M586 was abandoned.

The catalyst can be prepared separately from tetrahydrofuran, FeCl₃ and SOCl₂, which makes it possible to operate the polymerization process continuously.  Additional thionyl chloride is added in that case together with the reactants.

For the manufacture of M620, the molar ratio of tetrahydrofuran to othylene oxide is 2 : 1 and the catalyst requirements are 0.1 mol FeCl₃ per 100 mols reactants and 5 mols SOCl₂ per 100 mols reactants.  The polymerization temperature is 25-35º C.  The polymerizate is left standing for several hours; the FeCl₃ is washed out with water, and water and unreacted tetrahydrofuran are removed by distillation.  Chlorine is removed by reaction with methanol and NaOH at 90-100º  in a closed vessel; excess methanol is distilled off; the mixture is neutralized with HCl and the NaCl formed is washed out.  After the addition of 0.5% by weight of iso-oxtylphenol (as stabilizer), the product is dried and filtered.

The ratio of tetrahydrofuran to ethyene oxide is 4:1 for the manufacture of M586.  The catalyst requirements are 0.1 mol FeCl₃ per 100 mols of reactants, and 2.5 mol SOCl₂ per 100 mols of reactants.  The polymerization temperature in this case is about 25-30º C.  The polymerizate is left standing for several days and neutralized (Congo Red) with NaOH.  The unreacted tetrahydrofuran is distilled off, phenol and caustic are added to the polymerizate and the mixture is heated to 165º C. until no organic chlorine can be detected.  The reaction product is then treated with water and neutralized with HCl.  After the addition of 0.3% by weight (calculated on finished product) of isooctylphenol, the water is removed by distillation, the product is diluted with naphtha, filtered and freed from the solvent.

Inspection Data of Synthetic Oils.

Inspection data of the synthetic oils from copolymerization of tetrahydrofuran and ethylene oxide are given as follows:

Both oils are not miscible with paraffin hydrocarbons, but are soluble in alcohols, ethers, ketones, esters, and aromatic hydrocarbons.

W.F. Faragher, U.S.A.
C. C. Chaffee, U.S.A.
D. A. Howes,  U.S.A.
H. Schindler,    U.S.A

Additive for Break-In Oil

Summary

An additive for the lubricating oil used during the break-in period of engines, mainly aircraft engines, has been developed at Leverkusen.  By the use of the additive it was possible to reduce the break-in time of German aircraft motors from 70 hours to 20 hours and to eliminate rejects.

The effective compound in the additive is dichlorodiphenyl-phosphorous acid ("Product 891")

To increase the solubility in oil, the compound is used in the form of its stearylamine salt and to further increase ease of handling the additive was distributed as a solution in alcohol-benzol (50:50).  The solution which contains 50% by weight of the stearylamine salt of Product 891 was termed J7.  The break-in oil for aircraft engines consisted of Rotring Oil (RedBank) with 2% by weight of J7.  The information was obtained by interrogation of Dr. Berthold Wenk, manager of the dyestuff department, on July 5 and 6, 1945.

Preparation.

The preparation of the additive is based on the following reactions:

The 1240 kg. of chlorobenzene and 760 kg. of PCl₃ is added, with stirring, 372 kg. of AlCl₃.  Since no reaction takes place in the cold, the temperature is rapidly broutht to 70-75ºC.  Development of HCl begins, and heating is continued according to the following schedule:

Express PCl₃ and some chlorobenzene are distilled off at atmospheric pressure until no PCl₃ can be detected in the overhead product; the residue is cooled to 70ºC. and distilled under vacuum at 81-136ºC during 708 hours.  Of the chlorobenzene charged, about 800 kg. is used in the reaction and 400 kg. is recovered.  The distillation residue is cooled to 50-55ºC. and passed by N₂ pressure into 2000 liters of water and 2,500 kg. of ice.  The yield of the crude moist product "Product 891" is 1200-1250 kg.

The following procedure is used for the purification of the crude product.

1200-1250 kg. of Product 891 is pasted with about 4000 liters of water, brought to the boiling point with direct steam, made weekly alkaline (phenolphthaleine) by the slow addition of about 250-300 kg. of Na₂CO₃ and boiled with direct steam for about 20 hours.  The solution, whose volume is not about 7000 liters, is treated with about 250-300 kg. of concentrated HCl (technical) until it is barely alkaline (Brilliant Yellow indicator) and is then filtered at about 90-95ºC.  The residue is again pasted with 3000 liters of water, made alkaline (phenolphthaleine) with about 60 kg. of Na₂ CO₃, boiled for 6 hours, treated with about 40 kg. of Hcl (weak indication of brilliant-yellow paper) and filtered.  The filterates of the two treatments are combined and acidified in portions of 1500 liters (strong Congo Red) with HCl; the reaction is carried out in an enamelled vessel or 2500 liter capacity.  The total consumption of HCl is about 400 kg.  Product 891 separates out as a viscous oil, which settles to the bottom of the vessel and the supernatant solution is drawn off.

If the product still does not give a clear solution in a Na₂CO₃ solution, it is necessary to repeat the soda treatment.  The total product obtained is dissolved in about 1000 liters of water, together with about 40-50 kg. of Na₂CO₃ (weakly alkaline towards phenolphthalein), boiled for 1/2 hour, made weakly alkaline toward Brilliant Yellow by means of HCl and filtered; the solution is again acidified in an anamelled vessel.  The separated oil is repeatedly washed with water at 50-60ºC. and the product is finally dried under vacuum at 135-140ºC.  Yield:  500-550 kg. of pure Product 891.

The preparation of the stearylamine salt and solution of the salt in alcohol and benzol is carried out in one step as follows:  800 kg. of pure Product 891 is heated to 60ºC., 500 kg. of benzol is added with stirring and after complete solution 500 kg. of alcohol (94%) is added.  The temperature has sunk to 40ºC. by this time, and 200 kg. of stearylamine (well broken up) is added within about 1 hour.  The temperature is maintained at 40-45ºC. by cooling during this period.  After complete solution has taken place, stirring is continued at 40-45ºC. for 2 hours and is then filled into glass containers.  Yield:  2000 kg. of J7.

Iron drums as well as galvanized or lead lined drums are not suitable for shipping the product.

Specifications for J7.

The following specifications have been proposed by the I.G. Leverkusen for the additive J7 for use by the German Air Force:

Development Work.

In the course of the laboratory work to find a suitable additive for break-in oil, the following compounds were tested and found unsuitable: