NOVEL BISAMIDES CONTAINING FLUORINE

United States Patent Office 3y786,093 3,786,093 NOVEL BISAARDES CONTAINING FLUORINE Bernard M. Lichstein, Elizabeth, and Robert J. Du Bois, Morristown, N.S., assignors to Alfied Cheniical Corpo- 5 ration, New York, N.Y. No Drawing. Filed Oct 17, 1969, Ser. No. 867,372 Int. Cl. C07c 103130 U.S. Cl. 260-561 HL 7 CWms 10 ABST'RACT OF THE DISCLOSURE Novel compounds useful in imparting oil repellency to fabrics have the formula (RFCONH) 2CHR wherein Rf is a radical containing at least one fluorine atom and from 1 to 20 carbon atoms, the radical being selected from the 15 group consisting of alkyl, phenyl, alkylphenyl, phenylalkyl, and any of these radicals containing an ether link-- age, and R is hydrogen, trichloromethyl, or phenyl. The compounds are prepared by reacting a nitrile of the formula RFCN with formaldehyde, chloral, chloral hydrate 20 or benzaldehyde in the presence of a catalytic amount of a strong acid and preferably also in the presence of a solvent such as carbon tetrachloride. 25 BACKGROUND OF THE INVENTION T'his invention relates to novel bisamides containing fluorine. It is desirable to impart soil and stain repellency to fabrics used in apparel, upholstery, draperies and similar applications. A current method used to impart soil and stain repellency to fabrics involves coating the fabric with an oil repellent compound. 'fhe coating is normally applied using common textile finishing techniques, such as by treating the fabric with a padding bath of a solution or aqueous dispersion of the compound or by spraying the surface of the fabric with the compound. In order to be suitable in such coating applications, a compound must possess certain critical properties in ad- 40 dition to oil repellency; for example, the compound must be capable of forming a uniform and even coating of proper thickness on the fabric and the coating must adhere well to the fabric and must not be easily removed by physical or chemical means. Other critical properties 45 which the conipound must possess are appreciated by those skilled in the art, but the suitability of a particular class of compounds in such applications can only be determined by empirical methods. It is an object of this invention to provide a class of 50 novel compounds useful for imparting oil repellency to fabrics and other textile materials. SUMMARY OF THE INVENTION This invention provides compounds capable of impart- 55 ing oil repellency to fabrics, said compounds having the formula (RfCONH)2CHR wherein Rf is a radical containing at least one fluorine atom and from I to 20 carbon atoms, the radical being selected from the group consisting of alkyl, phenyl, alkylphenyl, phenylalkyl, and any 60 of these radicals containing an ether linkage, and R is hydrogen, trichloromethyl or phenyl. The Rf radical can be perfluorinated or can contain any lesser number of fluorine atoms down to at least one. As used herein, the 65 term "alkyl radicals" includes both straight and branched chain radicals. The compounds of this invention are prepared by reacting a nitrile of the formula RFCN, wherein Rf has the group consisting of formaldehyde, chloral, chloral hydrate, and benzaldehyde, in the presence of a catalytic Patente,d Jan. 15, 1974 2 arnount of a strong acid. The following aldehydes d(> not produce a detectable amount of the desired bisamide: mnitrobenzaldehyde, p-chlorobenzaldehyde, phydroxybenzaldehyde, p-methoxybenzaldehyde, pformylbenzoic acid, and the trimer of dichloroacetaldehyde.. The formaldehyde can be present in its monomeric form or in the form of a cyclic polymer, such as trioxane, or in the form of a linear polymer, such as paraformaldehyde. Trioxane is the preferred form of formaldehyde. Suitable catalysts include sulfuric acid, hydrochloric acid, phosphoric acid, zinc chloride, ferric chloride, stannic chloride, and strongly acidic resins, such as Amberlyst 15, which is a crosslinked resin containing pendent--SO37H+ groups. The catalyst is preferably present in an amount of about 1% by weight based on the total weight of the reactants. Greater c@r lesser amounts of catalyst can be used if desired, but it is preferable not to use more than the minimum amount required to maintain a moderate rate of reaction. An excess of catalyst contributes to undesirable hydrolysis of the nitrile. The reaction is preferably carried out in the presence of an inert solvent, suc,,h as chloroform or carbon tetrachloride. The temperature of the reaction is not especially critical and can range from O' C. up to the reflux temperature of the solvent. When formaldehyde is used as the reactant, there is also obtained as a by-product of the reaction a hexahydro-s-triazine having the formula Rf @=0 CH2 CH2 I I RF-C-N 11-0-Rf II \ / 8 0 CHS wherein Rf is the same as in the bisamide product. These hexahydro-s-triazines are also novel compounds and are claimed in copending application Ser. No. 867,370, now U.S. Pat. No. 3,657,235, filed concurrently herewith. The best mode contemplated for preparing the compounds of this invention is to react the appropriate nitrile with trioxane, choral hydrate or benzaldehyde in the presence of about 1% by weight. of concentrated sulfuric acid as catalyst, and also in the presence of carbon tetrachloride as solvent, the reaction being carried out under reflux for a period of from one to two hours. The compounds of this invention can be applied to fabrics to render them oil repellent by dissolving the compound in a suitable solvent, such as acetone, and then treating the fabric with the compound in solution, followed by removal of the solvent by evaporation. In some instances it is desirable to heat the treated fabric at moderately elevated temperatures, such as from about 120 to 160' C., for a brief period, such as about 5 minutes, in order to set the coating of the compound on the fabric. Fabrics thus treated exliibit greater oil repellency than untreated fabric. In comparison, fabrics treated with the nonfluorine-containing analogs of the compounds of this invention exhibit no improvement in oil repebency over untreated fabric. DESCRIPTION OF THE PREFERRED EMBODIMENTS The preferred compounds of this invention have the meaning given above, with a reactant selected from the 70 formula (RfCONH)2CHR wherein RI has the formula Y ( C F 2 ) m ( C H 2 ) n 7 -

1 31786,093 3 wherein m is an integer from 2 to 10, n is an integer not greater than m from 0 to 4, and Y is selected from the group consisting of F3C- and radicals having the formula RI F-@-R2 F-@-0- F-@-R2 I ,Kl wherein R, and R2 are independently fluorine or perfluoroalkyl groups having from one to two carbon atoms, the total number of carbon atoms being not more than 20. In especially preferred embodiments of this invention, R, and R2 are fluorine, m is 2 to 5, and n is 0 to 2. Nitrile reactants having the formula CF3(CF2,)m(CH2)nCN are known compounds and can be made from commercially availlable materials in @aCCOTdance with known methods. Nitrile reactants having the formula RI F-@-R2 F-@-0-(C F2). (C E[2).CN RI can be prepared from telomer halides having the formula RI F-@-R2 F-@-0-C F2C F2(C F2C F2)@(CH2CI12).E F-@-R2 I RI wherein R, and R2 have the afore-stated mean'mgs, w and x are integers representing the respective degrees of telomerization, and E is bromine or iodine. These telomer halides and their method of preparation are described in U.S. Pat. 3,514,487. The telomer halides are prepared by reacting telogens of the formula P.i F-@-R2 F-@-0-CF2CF2E F-@-R2 I Ri with telomerizable unsaturated compounds, i.e., tet rafluoroethylene and ethylene, the reaction being initiated by heat of free radical catalyst. The telogens are prepared by react@ing the corresponding perfluorinated ketone with an ionizable fluoride salt, e.g. CsF, to form the corresponding organic salt, and then reacting the organic salt with tetrafluoroethylene and either bromine or iodine. Preparation of the telogens is described in greater detail in U.S. Pat. 3,453,333. Nitrile reactants wherein n is zero can be prepared by reacting the corresponding telomer halide with ICN or (CN)2 at pressures above 20 atmospheres and at temperatures above 300' C. Nitrile reactants wherein n is greater than zero can be prepared by reacting the corresponding telomer halide with an alkali metal cyanide in the presence of dimethyl sulfoxide at temperatures between 60 and 100' C. The nitriles and their method of preparation aTe described in greater detail in Canadian Pats. 823,673 and 823,674, corresponding to U.S. applications Ser. Nos. 721,115 and 721,117, respectively, both U.S. applications having been filed on Apr. 12, 1968. The nitriles normally contain an even number of hydrocarbyl and fluorocarbyl groups following the perfluoroalkoxy group. However, nitrilescontaining an Gdd num4 acting the telomer halide with sulfur trioxide, followed by hydrolysis of the reaction product to obtain the acid, from which the nitrile can be prepared in accordance with known methods. Also, the acid thus formed can be converted to the corresponding telomer iodide for further telomeiization by reaction with alkali-free silver oxide to form the silver salt, followed by Teaction of the silver salt with powdered iodine to form the telomer iodide. In adidtion to giving preferred results when applied to 10 fabrics as conventional oil repellent agents, the preferred compounds of this invention have the additional utility of being capable of imparting oil repellency directly to fibers extruded from a composition of a fiber-forming synthetic resin and about 1% by weight of the com15 pound. This particular use of the more preferred compounds of this invention is the invention of two of our coworkers and is disclosed in copending U.S. application SN ' 867,368, now U.S. Pat. No. 3,646,153, filed concurrently herewith. 20 The following examples further illustrate the invention. In each of the examples the product was identified by elemental, infrared spectrum, and nuclear magnetic resonance analyses. EXAMPLE I 25 A mixture of 15 grams of 5-perfluoroisopropoxy-5,5,4, 4-tetrafluorovaleronitrile, 25 ml. Of CC14, and 0.2 gram of concentrated H2SO4 were brought to reflux. A solution of 1.34 grams of trioxane in 45 ml. Of CC14 was added 30 over a period of one hour. The mixture was maintained at reflux for an additional 75 minutes. On cooling, the mixture separated into two layers. Each layer was dissolved in ether, washed with dilute NAOH and then water, dried over MgSO4, and then stripped of solvent under 35 vacuum. There was thus obtained from the bottom layer 3.2 grams of dried solid, 77% pure by gas chromato@ graphic analysis, which was identified as bis(5-perfluoroisopropoxy-5,5,4,4 -tetrafluorovaleroamido) methane. 40 EXAMPLE 2 The general procedure of Example 1 was followed except the reaction mixture contained 65.0 grams of 7perfluoroisopropoxy - 7,7,6,6,5,5,4,4 - octafluoroheptanonitrile, 4.6 grams of trioxane, 0.7 gram of concentrated 45 H2SO4, and 150 ml. Of CC14- The by-produc@ 1,3,5-tris(7-: perfluoroisopropoxy - 7,7,6,6,5,5,4,4-octafluoroheptanoyl) hexahydro-s-triazine, was removed from the reaction mixture by recrystallization from CC14. The mother liquor was then stripped of solvent and the resulting residue 50 was recrystallized from petroleum ether to yield 7.0 grams of dried solid which was identified @as bis(7-perfluoroisopropoxy - 7,7,6,6,5,5,4,4- octafluoroheptanamido) methane. EXAMPLE 3 55 The general procedure of Example 2 was followed except the reaction mixture contained 5.1 grams of perlluorobenzonitrile, 0.8 gram of trioxane, 0.1 gram concentrated H2SO4, and 50 ml. Of CC14. The product was a 60 white solid, melting point 135' C., which was identified as bis(perfluorobenzamido)meth-ane. EXAMPLE 4 65 A mixture of 5.3 grams of benzaldehyde, 10.0 grams of 7 - perfluoroisopropoxy - 7,7,6,6,5,5,4,4 - octafluoroheptanonitrile and 10 ml. of concentrated H2SO4 was stirred at about room temperature for one hour. Water was added !and the oil which separated was treated with 70 methylene chloride, which produced solids which were washed with hot benzene. The benzene-insoluble material was recrystallized from CH3CN to give 0.7 gram of a white solid, melting point 113-114' C., which was identified as bis(7 - perfluoroisopropoxy - 7,7,6,6,5,5,4,4-octaber of either group or both groups can be propared by re- 75 fluoroheptanamido)phenylmethane.

5 EXAMPLE 5 A mixture of 3.3 grams of chloral hydrate, 8.8 grams of 7 - perfluoroisopropoxy - 7,7,6,6,5,5,4,4 - octafluoroheptanonitrile, 10 ml. of concentrated H2SO4 and 50 ml. of chloroform was stirred at 25' C. for 17 hours. The mixture separated into two layers and the lower layer was treated with water which produced solids which were dissolved in ether, washed with water and dried using Na2SO4 and 3A molecular sieves. The solvent was removed by vacuum and the residue was recrystallized from chloroform to give a solid melting point 136-138' C., which was identified as 2-bis(7- perfluoroisopropoxy7,7,6,6,5,5,4,4 - octafluoroheptanamido) - 1,1,1-trichloroethane. We