US3714273A - Fluorine containing adamantanes and bicyclo [2.2.2] octanes - Google Patents

Abstract

Compounds of the formulas

WHEREIN N 0 TO 3 INCLUSIVE, AND Z1, Z2 and Z3 are each (CH2)n-CF3, saturated lower alkyl or hydrogen are useful as heat transfer fluids and as working fluids in Rankine cycle engines.

Description

United States Patent 1 Tullock 1 Jan. 30, 1973 [54] FLUORINE CONTAINING Chem. and Eng. News 47 15 (1969).

ADAMANTANES AND BICYCLO [2.2.2] OCTANES Primary ExaminerDaniel D. Horwitz Attorney-D. R' J. Boyd [75] Inventor: Charles William Tullock, Landenbefg, 57 ABSTRACT [73] Assignee: E. l. du Pont de Nemours and Com- Compounds of the formulas pany, Wilmington, Del. "153 31 1,", f b iii [22] Filed: Sept. 29, 1970 A [21] Appl. No.: 76,587 or z Za [52] US. Cl. .260/648 F, 252/73, 424/352 [51] Int. Cl ..C07c 23/20, C070 17/22 [58] Field of Search ..260/648 F whflein n 0 to 3 inclusive and Z2 and 23 are [56] References Cited each (CH ),,-CF saturated lower alkyl or OTHER PUBLICATIONS Sohar et al., Chem. Abstracts 72, 16944h (1970).

hydrogen are useful as heat transfer fluids and as working fluids in Rankine cycle engines.

7 Claims, N0 Drawings FLUORINE CONTAINING ADAMANTANES AND BICYCLO [2.2.2] OCTANES FIELD OF THE INVENTION This invention is concerned with a new class of power fluids of unusual stability and heat-exchange capacity.

BACKGROUND Power fluids for use in closed Rankine-cycle turbine engines require exceptional stability to heat in the presence of metals used in engine construction. If a single stage turbine engine is used, they must further be characterized by high vapor density so that the speed of the turbine is not excessive, and by a moderately high molecular weight (e.g., 150).

SUMMARY OF THE INVENTION There have now been discovered the bridgehead (fluoroalkyl-substituted), multicyclic, saturated hydrocarbons characterized by having a molecular weight above 200, a boiling point in the range of 170300 C. and a critical temperature at least 175C. above the boiling point. These compounds are stable at 300C. in the presence of selected metals for a time period in excess of 90 days. The compounds are the adamantanes and bicyclo[2.2.2]octanes, in which at least one bridgehead carbon carries a substituent (CH ),,CF in which n is 0, l, 2, or 3; the remaining bridgeheads carry (CH ),,-CF saturated lower alkyl of up to four carbon atoms or hydrogen; and all non-bridgehead positions carry hydrogen. These compounds have the formulas:

I in which each of Z, Z, and Z is --(CI-I,),,CF5, saturated lower alkyl or hydrogen, n being defined as above.

In these compounds it is important that the non bridgehead ring positions be CH groups. Any substitution at these positions often decreases the heat and chemical stability of the compound. It is particularly important to avoid fluorine substituents at nonbridgehead ring positions.

Preferred compounds of Formulas l and 11 are those in which n is or 1, particularly those in which n is 0, and Z, Z, and Z is hydrogen or methyl.

The cyclic skeletons of the compounds of this invention are composed entirely of six-membered aliphatic carbon rings. All the ring carbons are either bridgehead carbons or CH groups. The term bridgehead carbon defines a carbon atom connected directly to three other carbon atoms (i.e., CH groups) and having only its single remaining bond available to carry hydrogen or a substituent as defined above.

The selected metals against which the compounds of this invention are stable in excess of 90 days at 300C. include copper, 1020 cold rolledsteel, 304 stainless steel, and aluminum. The tests are carried out in the absence of air and moisture. A compound is rated stable if the maximum result of the heat treatment is a color change or deposition of a thin coating on the surface of the metal and there is no gross chemical breakdown of the compound.

Because of their unusual stability to heat in the presence of metals, the compounds of this invention are all useful as heat-exchange fluids for all equipment in which fluid heat-exchange is carried out as well as power fluids in closed Rankine-cycle turbine engines.

A closed heat-exchange or power system is advantageous for employing the compounds of this invention since the vapors of the fluids are toxic to rats in acute inhalation toxicity experiments and are presumably toxic to humans. Appropriate care must be exercised to prevent escape of the vapors, particularly at high temperatures.

A process suitable for making the compounds of the invention is that of Smith, US. Pat. No. 2,859,245. In this process an adamantane or bicyclo[2.2.2]octane having on at least one of its bridgehead positions a carboxy, or a carboxyalkyl group is treated with sulfur tetrafluoride to convert the COOH group to a CF;, group. The chemistry of the process may be represented schematically by the equation:

The hydrogen fluoride formed in this reaction apparently catalyzes the continuation of the process since the reaction does not proceed in the presence of a strong absorbent for hydrogen fluoride such as sodium fluoride. On the other hand, addition of hydrogen fluoride beyond the amount formed is not necessary since this favors fluoride substitution on other bridgehead carbon atoms to yield byproducts of poor thermal stability. It is for this reason that it is advisable to carry out the process in the absence of moisture since water reacts readily with SF to produce HF.

No added reaction medium is required for carrying out the process of this invention. However, as shown in the examples, the reaction may be carried out in the presence of a liquid which is inert to the reactants and products, s'uch as l,2-difluorotetrachloroethane.

The process may be carried out at temperatures in the range from 0-200C. and preferably in the range from SO -C. Pressure is not a critical variable in the process and pressures above and below atmospheric pressure may be used.

The molar proportions of sulfur tetrafluoride to carboxylic acid, which may be brought together to bring about the reaction of this invention are not limited in any way. Any proportion of the two reactants will produce at least some of the trifluoromethyl product. For practical purposes it is easiest to isolate the desired product when the molar proportions of SP to COOH are within the range from 10:1 to 1:1 and best yields are obtained in the range from 4:1 to 2:1.

' The products are isolated by known means such as by distillation, chromatography, and the like. Isolation of a pure product is particularly desirable since impurities can decrease the thermal stability of the product.

Adamantane' carboxylic acids are well known. Thus adamantane-l-carboxylic acid is described by H. Stetter and E. Rauscher, Chem. Ber., 93 1 161 (1960);

'mantane-7-carboxylic acid have been disclosed by H.

Koch and .1. Franken, Chem. Ber. 96, 213-9 (1963). Likewise, bicyclo[2.2.2]octane-l-carboxylic acid has been disclosed by C. Grob, M. Ohla, E. Renk and A. Weiss, Helv. Chim. Acta 41, 1191-7 (1958) and bicyclo[2.2.2]octane-1,4-dicarboxylic acid by J. C.

Kauer, R. E. Benson & G. W. Parshall, J. Org. Chem- 30, 1431-6 (1965). The synthesisof bicyclo[2.2.2]octane-l-carboxylic acid with various alkyl substituents substituted in the 4 position has been described by H.

r). Holtz and L. M. Stock, .1. Am. Chem. Soc. 86,

5183-8 (1964), and by Whitney et al., J. Medicinal Chemistry 13, 254 (1970).

Carboxylic-acid groups can be inserted in vacant bridgehead positions of adamantanes or substituted adamantanes by carbonylation as shown in Example 14 of the appended examples.

Homologues of adamantane carboxylic acids can be made by application of the Arndt-Eistert reaction to the carboxylic acid as shown by H. Stetter, M. Schwartz and A. A; Hirschhorn, Chem. Ber. 92, 162935 (,1959) who employed this reaction to make adamantane-lacetic acid. Cfo, Fieser and FiesenAdvanced Organic Chemistry, Reinhold Publishing Corp., New York, N. Y., 1961 pp. 386-388.

C'arboxylic acids can also be made from halides such as chlorides, bromides or iodides by forming a Grignard reagent, reacting the Grignard reagent with carbon dioxide and hydrolyzing the product. Thus l-adamantyl acetic acid has been made from l-(bromomethyl)-adamantane by this route by N. F. Stepanov and V. F. Baklos, Zh. Obsch-Khimf 34, 579-84 (1964). H, Stetter and P. Goebel have shown that l-bromo-adamantane can be reacted with ethylene in the presence of aluminum bromide to form l-ada'mantyle thylenebromide. The latter compound can be converted to the 3-substituted propionic acid as described above.

K. Bott, Angew, Chem. 77,967 (1965) has described yet another .route' to adamantane substituted at a bridgehead with an acetic acid group.

The Arndt-Eistert reaction can likewise be used to prepare higher homologues of bicyclo[2.2.2]octane monoand dicarboxylic acid.

In the examples which follow, parts and percentages are by weight unless otherwise specified. These examples are intended to illustrate the invention and are not intended to be limiting.

EXAMPLE 1 1-(Trifluoromethyl)adamantane l-Adamantanecarboxylic acid (34 g; 0.189 mole) and sulfur tetrafluoride (63 g; 0.583 mole) were heated in a 235-ml Hastelloy pressure reactor, free of air, at 50C for 1 hour, 75C for one hour, 100C for 1 hour, and at 125C for 1 hour. The crude product (37.4 g). was washed with 5% NaOH solution to remove hydrogen fluoride and any adamantanecarboxylic acid fluoride, taken up in 1,1,2-trifluorotrichloroethane,

washed with water, the solution dried over MgSO, and the product distilled through a 6-inch spinning band column. There was obtained 29.5 g of a colorless,

somewhat viscous liquid with a camphor-like odor, bp

-81C/20 mrn. Vapor phase chromotographic analysis indicated the product was 93.8 percent 1- (trifluoromethyl)adamantane, and that 5.8 percent of a minor component was present. Fluorine nuclear magnetic resonance spectra revealed as major peaks a large singlet in the CF region for the product, with a much smaller doublet in the CF;; region; the areas of the two peaks were present in about a 15:1 ratio. The impurity was identified as 3-fluoro-l-(triflu0romethyl)adamantane. The single bridgehead fluorine splits the CE, fluorinespectrum into a doublet.

' A pure sample of l-(trifluoromethyl)adamantane was recovered by a vapor phase chromatographic separation. Anal. Calcd. for C,,H, F C, 64.7; H, 7.35; F, 27.9

Found: C, 64.6; H, 7.30; F, 28.5. The boiling point of the pure product at atmospheric pressure as obtained by differential thermal analysis (DTA) was 200C; the pure compound melted at 8C. The critical temperature was found to be 419C.

Pure l-(trifluoromethyl)adamantane exhibited exceptional heat stability. Test portions of thisv material were heated in sealed evacuated Pyrex tubes at 350C in contact with strips of copper, 1020-ordinary coldrolled steel and 304-stainless steel for l 13 days without noticeable change in the liquid. The copper and 304 metal coupons became dulled during this period; the 1020 steel developed a firm steeLblue coat on the metal surface.

A similar series of heat stability tests of 1- (trifluoromethyl)adamantane with a control tube as well as tubes containing strips of copper, aluminum, 1020-ordinary steel and 304-stainless steel were run at 300C for 108 days. No change either in the fluid or the metal surface was noted in any of the five tubes, except for a slight darkening of the 1020-ordinary steel surface.

This combination of exceptional heat stability not only alone but in contact with metals, and a spread of 219C between the critical temperature and boiling point in combination with a boiling point of 200C and a molecular weight of 204 make the material an excellent working fluid for an air-cooled turbine operating in a closed Rankine cycle.

EXAMPLE 2 l-Adamantanecarboxylic acid g; 0.56 mole) was placed in a Hastelloy pressure reactor which was closed and warmed at 5060C for 1 hour under a vacuum below 1 mm to remove traces of moisture from the acid and the reactor. .The reactor was then closed while still under high vacuum, cooled to 7 8C and sulfur tetrafluoride (180 g; 1.67 mole) was added. The reactants were then warmed with gentle rocking at 50C for 2 hours and at 75C for 8 hours. The crude product was warmed with stirring with a solution of 50 g of KOH dissolved in 500 ml of water at 7075C for 6 hours. This removed the small amounts of hydrogen fluoride present and the slowly hydrolyzable l-adamantanecarboxylic acid fluoride. The product was next dissolved in an equal volume of 1,1,2-

trifluorotrichloroethane. This solution was washed with water, dried briefly and concentrated. The product remaining was next stirred with 500 ml of concentrated H SO at room temperature for 16 hours to remove the bridgehead-fluorinated impurities. The product was separated from the heavier light brown colored sulfuric acid layer and dissolved in 1,1,2- trifluorotrichloroethane. The resulting solution was washed in water, dried briefly and distilled through a 6- inch spinning band column. There was obtained 88.2 g

with stirring with a solution of 40 g of KOH in 300 cc of water at 5068C for 2.25 hours, to remove small amounts of hydrogen fluoride and adamantanecarboxylic acid fluoride. The product was next taken up in an equal volume of l,l,2-trifluorotrichloroethane, dried briefly and distilled through a 6-inch spinning band column; 30.7 g of material, bp 7577C/l4 mm was recovered. Vapor phase chromatographic analysis indicated the product was 30% 1 ,3- di(trifluoromethyl)adamantane and 60.8% 1,3- di(trifluoromethyl)--fluoroadamantane. A portion of the distilled product was subjected to vapor phase chromatographic separation. There was recovered 1.41 g (amounting to 41 percent) of 1,3- di(trifluoromethyl)adamantane (A) and 2.04 g (amounting to 59 percent) of l,3-di(trifluoromethyl)- 5-fluoroadamantane (B).

Fluorine nmr of (A) showed the presence of a single large fluorine peak in the CF, region which had no fine TABLE 1 [Preparation of 1-(trifluoromethyl) adamantane] Product purity Hastelloy based reactor 011 VPC size analysis Conver- Example Reactants Moles (m1.) Reaction conditions (percent) sion 1-Ad-C02H 0.139 235 C. for 8 hours with rocking, then stood at 82 3 SF, 0. 41s 25 0. for an additional 8 hours. 4 l-Ad-COgH 3.5g; 035 50 C. for 8 hours 85 67 O 5 3 3 333% 235 {22 81 i8? 3 1335213131131 :jjj} 17 l-Ad-COJI 0.139 235 50 C. for 1 hour o 0,41 75 C. for 1 hour. M 76 100 C. for 4 hours 7 Hui-(.0 11 235 125 for 8 hours an 53 F .'..7 8 l-Ad-UOdl g 800 125 (F. for 8 hours 72 1g 4 l .c0 11 0.13!) 120' C. for 8 hours 00 60 J SF, 0. 416

m.l of Freon112 Vapor phase chromatography. *1,2-difluor0tetrachloroethane.

EXAMPLE 10 l,3-Di(trifluoromethyl)adamantane Adamantane-l,3-dicarboxylic acid (20 g; 0.089 mole) and SF, g; 0.555 mole) were heated in a 235- ml Hastelloy pressure reactor, free of air, at C for 1 hour, C for 1 hour, and 125C for 8 hours. The crude product recovered was first stirred with excess 15% KOH solution at 6065C for 20 minutes. Infrared analysis indicated by absorption at 5.45 p. the probable presence of carboxylic acid fluoride, so the product was warmed again with stirring with a solution of 20 g of KOH in 200 m1 of water at 59-69C for 2 hours. The product, now free of the 5.45 p. impurity, was distilled through a 6-inch spinning band column; there was recovered 8.67 g of 1,3- di(trifluoromethyl)adamantane in the form of a colorless liquid, bp 83.0-83.8C/13 mm. Vapor phase chromatographic analysis indicated the product was 90-92% pure.

EXAMPLE 1 l l,3-Di(trifluoromethyl)adamantane Adamantane-l,3-dicarboxylic acid (35.0 g; 0.156 mole) and sulfur tetrafluoride g; 0.972 mole) were heated with rocking in a Hastelloy pressure reactor, free of air, at 75C for 1 hour, 100C for 1 hour, and C for 8 hours. The crude product was warmed structures even on high resolution. Vapor phase chromatographic analysis indicated the product was 98.7% pure.

Anal. Calcd. for C H F C, 52.9; H, 5.2: F, 41.9

Found: C, 53.1; H, 5.0; F, 42.1 The compound boiled at 208C at ordinary pressure (DTA its critical temperature was 409C.

Fluorine nmr of (B) showed the presence of a large doublet in the CF region, and a second peak which had no fine structures even under high resolution; the two peaks had areas which approximated a 6:1 ratio. Vapor phase chromatographic analysis indicated the compound was 97.4 percent pure.

Anal. Calcd. for C, H F C, 49.6; H, 4.5; F, 45.9

Found: C, 49.7; H, 4.1; F, 46.0.

Another portion (10 g) of the original distillate containing 30% l,3-di(trifluoromethyl)adamantane and 50 ml of 98 percent sulfuric acid were stirred at room temperature for 18.5 hours. The acid insoluble fraction was taken up in 1,1,2-trifluorotrichloroethane and distilled through a 6-inch spinning band column; 2.38 g of 1,3- di(trifluoromethyl)-adamantane, bp 89.5C/ 16.5 mm was recovered.

Heat stability studies with l,3-di(trifluoromethyl)- adamantane at 350C in sealed evacuated Pyrex glass tubes in contact with selected metals indicate the fluid is exceptionally heat stable. After 97 days under these conditions, 304-stainless steel was unaffected, while lVUv-r e...

the surface of the copper coupon was only moderately dulled. The 1020-ordinary steel had a thin blue-violet colored coat. in no case was the fluid itself noticeably changed.

EXAMPLE 12 1-(2,2,2-Trifluoroethy1)adamantane LAdamantaneacetic acid (25 g; 0.129 mole) and sulfur tetrafluoride (42 g; 0.389 mole) were heated with rocking in a 235-ml Hastelloy pressure reactor, free of air, at 75C for 1 hour, 100C for 1 hour, and 125C for 8 hours. The crude product (30.5 g) was washed with percent aqueous sodium hydroxide, but this did not remove all the organic acid fluoride present. The product was next stirred at 5060C for 2 hours with excess NaOH solution. The product was taken up in an equal volume of 1,1,2- trifluorotrichloroethane, the solution washed with water and dried over MgSO Distillation yielded the three following cuts:

Vapor Phase Chromatographic Cut No. BP "Clmm Weight Analysis 2.34 g (C) 63.8% (D) 34.0% (C) 50.3% (D) 47.5% (C) 25.8% (D) 70.3%

Cuts 1, 2, and 3 were composited and subjected to a vapor phase chromatographic separation. The two major components present were separated and in about equal amounts. Compound (C) was 1-(2,2,2- trifluoroethyl)adamantane.

Anal. Calcd. for C ll F z C, 66.1; H, 7.8; F, 26.1

Found: C, 65.9; H, 7.9; F, 26.2.

Fluorine nmr of (C) showed the presence of one large fluorine peak in the CF region which under high resolution was a triplet. This was evidence for the CH,CF grouping. The compound had a boiling point of 217C (DTA) at ordinary pressure, and a critical temperature above 430C. No visible change in the fluid resulted on heating it-to 430C. The compound was heat-stable at 300C for 91 days in contact with 1020-ordinary steelin a sealed evacuated Pyrex tube; during this test a dark coat developed on the glass where liquid covered, the fluid developed a light yellow color and the surface of the metal coupon developed a dark coat. These tests showed that the compound is stable at 300C for extended periods. Compound (D) was l-(2,2,2-trifluoroethyl)-3-fluoroadamantane.

Anal. Calcd. for C,,H, -,F C, 61.0; H, 6.8; F, 32.2

Found: C, 61.2; H, 6.9; F, 31.5.

Fluorine nmr of (D) showed two different fluorine peaks in about 3:1 ratio. The larger peak under high resolution was a triplet and the smaller peak was a broad band with no fine structures, which would be expected for a fluorine on a tertiary carbon. The compound distilled at 233C at ordinary pressure (DTA) and underwent excessive degradation when heated to 260C in an effort to obtain the compounds critical temperature.

EXAMPLE 13 1-(Trifluoromethyl)-3,5-dimethyladamantane Crude l,3-dimethyladamantane-S-carboxylic acid (11 g; 0.053 mole), (prepared by reacting 1,3- dimethyladamantane with carbon monoxide in sulfuric acid) and 25 g (0.232 mole) of SF, were heated in a 235-ml Hastelloy pressure reactor at C for 1 hour and 125C for 3 hours. The 9.9 g of crude product recovered was warmed with stirring with a solution of 15 g of KOH in 100 ml of H 0 at 6575C for 2 hours. The product was extracted with 1,1,2 trifluorotrichloroethane. Distillation yielded 3.03 g of 1-(trifluoromethyl)-3,S-dimethyladamantane, bp 82C/10 mm; F nmr was in agreement with the proposed structure. Vapor phase chromatographic analysis suggested the compound was 88.2 percent pure. A pure sample was recovered by vapor phase chromatography. The compound boiled at 210C (by DTA analysis). lts critical temperature was 419C. Anal. Calcd. for C H F C, 67.2; H, 8.2; F, 24.6

Found: C, 67.3; H, 8.0; F, 25.1.

EXAMPLE 14 1 ,3-Di(trifluoromethyl)5 ,7-dimethyladamantane Part A A mixture of 50 g (0.305 mole) of 1,3-dimethyladamantane and 200 ml of concentrated sulfuric acid was heated at 150C for 4 hours under a pressure of 500 atmospheres of carbon monoxide. The product was mixed with ice and water. After extracting with 500 ml of warm carbon tetrachloride, the remaining solid was dissolved in excess 15 percent aqueous sodium carbonate. This solution was acidified to precipitate 37 g of crude 1,3-dimethyl-5,7-adamantanecarboxylic acid. This was purified by extracting twice with 500 ml of boiling diethyl ether and concentrating the ether extract to obtain 23 g of 1,3-dimethyl-5,7-adamantanedicarboxylic acid. I Anal. Calcd. for C H O C, 66.7; H, 7.9; NE. 126

Found: C, 66.6; H, 8.0; NE. 125

Part B i A mixture of 25 g (0.099) mole of 1,3-dimethyl-5,7- adamantanedicarboxylic acid and 60 g (0.556 mole) of SF was heated at 125C for 6 hours in a Hastelloy pressure reactor. The crude product was first heated with a solution of 30 g of R011 in 250 ml of water at 6065C for 2 hours. The remaining insoluble product was extracted with 1,1,2-trifluorotrichloroethane andthe extract distilled through a 4-inch Vigreaux column to obtain 20.3 g of 1,3-di(trif1uoromethyl)-5,7-dimethyladamantane, mp 52-57C, bp 92C at 11 mm and 218C at atmospheric pressure (DTA). Fluorine nmr showed a single fluorine peak in the CF region with no fine structure. Vapor phase chromatographic analysis indicated the product was 92.8 percent pure. Anal. Calcd. for C H F C, 56.0; H,6.0; F, 38.0

Found: C, 56.1; H, 6.1;F, 37.5.

EXAMPLE 15 1,4-Di(trifluoromethyl)bicyclo[g2.2.2]octane 1,4-Bicyclo[2.2.2]octanedicarboxylic acid (31 g; 0.157 mole) and sulfur tetrafluoride g; 0.787 mole) were heated with rocking in 235-ml Hastelloy pressure reactor, free of air, at 75C for 1 hour, C for 1 hour, and C for 8 hours. The crude product (29.6 g) was washed well with a solution of 20 g of KOH in ml of water, taken up in an equal volume of 1,1,2- trifluorotrichloroethane, this solution washed with water, dried over MgSO and distilled through a short 4-inch modified Vigreaux column. The material (17.1 g), which was a solid at room temperature, boiled at 167169C. A vapor phase chromatographic analysis indicated the product was 98.4 percent pure, it was subjected to a vapor phase chromatographic separation and the pure l,4-di(trifluoromethyl)bicyclo[10ctane as recovered was analyzed.

Anal. Calcd. for C H F C, 48.7; H, 4.9; F, 46.3

Found: C, 49.0; H, 5.1; F, 45.3.

The pure compound distilled at 171C at ordinary pressure (DTA); it melted at 5253C. The fluorine nmr showed a single large peak with no fine structure in the CF;, region. The material had a critical temperature of 360C.

Heat-stability tests with the material run at 300C in sealed evacuated tubes in contact with metals indicate this is an unusually heat-stable material. After 90 days at 300C there was a light dulling of the metal surfaces of copper, aluminum, 1020-ordinary steel and 304- stainless steel. The fluid itself was not noticeably changed in these or in a control experiment.

When the carboxylic acids listed in Table 11 below are substituted for l-adamantanecarboxylic acid in the procedure of Example 2 and proportional molar quantities of sulfur tetrafluoride are employed, the indicated trifluoromethyl derivatives are obtained.

TABLE II Item Carboxylic Acid Trifluoromethyl Product l-Methyl-B-adamantanel-Trifluoromethyl-3-methyladacarboxylic acid mantane 1,3,5-Trimethyl-7-adal-Trifluoromethyl-3,S,7-trimantanecarboxylic acid methyladamantane 3 l.3,5,7-Adamantanel ,3,S,7-Tetra(trifluoromethyl)- 4 tetracarboxylic acid adamantane Bicyclo[2.2.2]octanel-(Trifluoromethyl)bicyclowherein ri is 0 to 3 inclusive, and

Z, Z and Z are each (CH ),,CF saturated lower alkyl or hydrogen.

. l-Trifluoromethyladamantane. l,3-Di(trifluoromethyl)adamantane.

. l-(2,2,2-Trifluoroethyl)adamantane.

. l-(Trifluoromethyl)-3,S-dimethyladamantane.

. l,3-Di(trifluoromethyl)-5,7-dimethyladamantane. l,4-Di(trifluoromethyl)bicyclo[g2.2.2]octane.

Claims (6)

1. A compound having the formula

2. 1-Trifluoromethyladamantane.

3. 1,3-Di(trifluoromethyl)adamantane.

4. 1-(2,2,2-Trifluoroethyl)adamantane.

5. 1-(Trifluoromethyl)-3,5-dimethyladamantane.

6. 1,3-Di(trifluoromethyl)-5,7-dimethyladamantane.