2,410,635 Patented Nov. 5, 1946 2,410,635 HEAT STABLE COMPOSITIONS John Kenneth Graver, Webster Groves, Mo, as signor to Monsanto Chemical Company, St. Louis, Mo, a corporation of Delaware No Drawing. Application March 3, 1945, Serial No. 580,935 11 Claims. (Cl. 106-316) 1 This invention relates to heat stable composi tions and more particularly to heat stabilized compositions composed of aryl sulfonamides and aryl sulfones. 2 3 to 6 carbonv atoms; and an aryl sulfone of the formula type R 0 @“U s II Aryl sulfonamides such as benzene sulfona o mides, toluene sulfonamides and their N-alkyl in which R and R’ are residues selected from the derivatives are known to be relatively unstable under the in?uence of heat. This is true even when the sulfonamides are substantially free group consisting of hydrogen and methyl. Among the aryl sulfonamides employed in the from impurities. The aryl sulfona-mides have 10 preparation of the heat-stable compositions of the present invention are the following: benzene been found to possess the tendency of darkening sulfonamide and ortho- and para-toluene sul in color even upon standing at room temperature fonamides, and the following N-alkyl deriva and the phenomenon is greatly accelerated at tives of these sulfonamides, such as the methyl, temperatures above room temperature. When the sulfonamides are exposed to heat stability 15 ethyl, propyl, isopropyl, butyl isobutyl, amyl, iso amyl, hexyl, heptyl, octyl and ethylhexyl de tests, the compounds turn dark and the decom rivatives, and N-cycloalkyl derivatives such as position appears to progress rapidly. Aryl sul the cyclopropyl, cyclobutyl and cyclohexyl deriv fonamides, which have thus undergone decom atives. Mixtures of two or more of the afore position, are greatly lessened in value and ren described aryl sulfonamides may also be employed dered useless for many purposes for which the substances are normally used. This is particu for the purpose of the present invention. More» over, in the case of mixtures of the ortho- and larly true when the sulfonamides are employed para-isomers of the aryl sulfonamides such as the ortho- and para-toluene sulfonamides, the One of the objects of the present invention is 25 ortho- and para-isomers may be present in any desired proportions. to provide heat-stabilized compositions com Among the aryl sulfones employed in the prep posed of certain aryl sulfonamides and certain aration of the heat stable compositions of the aryl sulfones. present invention are the following: diphenyl A further object is to provide a process for heat sulfone and the ortho- and para-isomers of di stabilizing certain aryl sulfonamides. tolyl sulfone. Mixtures of the ortho- and para Further objects will become apparent from the isomers of the aforedescribed sulfones may Vary following description and examples. over a wide range of proportions. Mixtures of The composition of the present invention, gen two or more of the aforedescribed sulfones, to erally stated, comprises a blended mixture of at gether with ortho- and para-isomers thereof, may least one aryl sulfonamide of the formula type as plasticizers or extenders for cellulose esters, synthetic and protein coating compositions. be employed. SOZNELR’ R 40 in which R is a residue selected from the group consisting of hydrogen and methyl and R’ is a residue selected- from the group consisting of. hydrogen, alkyl radicals having from 1 to 8 car- - bon atoms and cyclo-alkyl radicals having from ‘ The heat stable compositions of the present in vention are prepared by blending the aryl .sulfon amides and the aryl sulfones in any desired man— ner, as for example by adding the sulfones to the sulfonamides and agitating the mixture until uniform dispersion of the components is e?ected. The quantity of aryl sulfone to be blended with aryl sulfonamides to provide the heat stable com positions of the present invention may range from 1 to 15% by Weight of the composition. The de 2,410,635 sired range is 5 to 15%. When substantially pure g. of diphenyl sulfone. The mixture was heated aryl sulfonamides are employed, the amount of to 153° C. and agitated until a uniform blend of sulfone required to provide a heat stable com the components was obtained. position may range in some‘ instances from 1 to E sample II 10%. When impure sulfonamides are employed, 5 the amount of sulfone required for the purpose IS A mixture of 65 parts Nqsopropylbenzene Sui hkely to be @n the range of 5 to 15%- In generel» fonamide, 25 parts of N-isopropyl- p-toluene sul no substantial improvement of the heat stability fonamide and 10 parts of a mixture of orthm of the composition is e?eeted when the amount ’ and para-ditolyl sulfone was heated to 50° C. and of sulfone present in the composition is increased 10 agitated to provide a uniform blend of the com_ above about 15%. The sulfones employed in the ponenta Preparation of_ the n°Ve1_ cempesltlons of the Compositions prepared as described in the fore present invention are solids at room. tempergoing examples as Well as others prepared ac_ ajture' It 15 one of the features of ‘thls _1I_1Ven' cording to the procedure in those examples, to tion that these sulfones impart heat-stability to 15 gather with Specimens of the corresponding aryl the Sulfonamldes _descnbed herelP when the em‘ sulfonamides containing substantially no aryl sul fones are present in the compositions of the presfones were tested for heat stability and the speci ent invention in amounts insu?icient to give rise mens were thereafter Compared with known color to ineompetlbmty m plague comeesltloes in Whmh standards. The heat stability test was performed the composltlons of the present Invention may be 20 by inserting the respective compositions and sul used‘ :I’Pe sulfene center‘? of ehe heat Stable fonamides into 13 mm. diameter test tubes and compositions of the present invention may be proimmersing the test tubes for one hour in an agi_ ‘need durmg the formetlfm °f the aryl summ' tated oil bath maintained at 205° c. The tem amide by a suitable selection of operating condiperature was selected because it provides a Drab tions, which under normal circumstances are 25 ?cal Safety factor above any temperature to usually controlled to avoid the formation of sulwhich the composition is likely to be exposed in fones. - . . - ‘ - molding operations where the compositions are . The.heat stable commiems of the pltesent used as plasticizers or softening agents for cel invention possess substantially the properties or lulose esters synthetic resins and protein coat_ characteristics of the aryl sulfonamides them- 30 mg Compositions The time S e1 ecte d for the test silgest’ gltlifiigx?ggogf tgséttgg 50511130213328 provides a practical safety factor in excess of the g the I: ult of ex Os r to otelgl em- time during which the composition is likely to beer gwhgll the heat gtabieucom sitions: of the extent of decomposition developed in the 53s‘ e tginpo Snail fro groom tenfaelite re to 20%‘, C an of thee res’ent inven? n r be subjected to such temperatures. A measure m 10 dies 18$ 35 composition when subjected to the heat test is ticizersp for example c)fora ceeltleu‘gseyeesters p‘the . provided according to the practice in this art by . . color com arison with known color stan ard . amount of aryl sulfones present in the plasticized The c 01 orpst an dards employed for compgrisoi ester as the result of their existence in the heat were those known as the Gardner 6 0101, Standards stable compositions of the present invention are 40 These standards were employed in conjunctiori ‘far less than’ the quantity. of my} Sulfones re." vwith‘ a comparator of the Hellige type in the (wired wi‘?ect any appreclame degree of mesh" manner known to those skilled in the art The 012mg actlon .On the ester‘ . . color is reported in terms of the Gardner number The following examples will serve to illustrate m . . of the respective standards used for the com_ D. _ . . 2211;561:1222;goTggzglggglggispggieiiDiem/2351:5532; 45 parison. By these standards the compositions ' ' . r . . . . “ prior to subjection to the heat test range in color merely as illustrative and not as limiting the mvennon' Emm Z 1 ' p e To 95 g. of benzene sulfonamide was added 5 ' No. from G_1 to G40 Moreover the color may vary within this range depending upon the impurities 50 present. The following table shows the results of the tests: I Composition or substance Eat-gig‘; Heat stability ((ilai'd?i; 0001‘5 1 2 3 Benzene sulfonamide ________________ __ Benzene snlfonamide; diphenyl sulfone N-isopropylbenzene sulfonamide _____ __ . é N-isgpropylbenzene sulfonamide;diphenyl sulfone _.-_. 7 _.___do___ 8 9 10 11 _____do 8 G-5 Very good. 1o G-2 Do. ~ _ ._ _ _ _ . _ _ _ _ _ _ __ N-butylbenzene sulfonamide _____________________________________________________ ._ N-butylbenzene sulfonami'de; dipbeiiyl suli'one.-. ____ __ __ p-Toluene sulionamide ________________ __ l2 p-Toluene sulfonamide; diphenyl sulfone. ,N-methy1-p~toluene sulionamide ....... __ ___ l4 N-methyl-p-toluene sulfoiiamide; dipheiiyl sulfone N-ethyl-p-toluene sulfonainide; diplienyl sulfone__ N-isopropyl-p-toluene sulfonamide ___________________ _. lg N-isgpropyl-p-toluene sulfonamide;diphenylsuli'one-.. 0 15 G-2 0 1O G-l8 G-lO gall-(.1 00 . Do. Do. Good. _ 0 10 6-10 Good. 0 (3-15 Poor. 10 (3-10 Good. ____ .. Poor. 0 (3-15 Poor. l2 G-12 Fair. 0 G~l8 Very poor. 13 ______ __'_ _____________________________________ __ G~15 Very poor. Good. . Very poor. __ N-ethyl-p-toluene sulfonami'denr ____________ __ l6 17 ._-__ G-l5 6-? G-l8 Ll, ______________________________________________________ .- 13 15 0 8 0 0 __________________________________________ _- 6 _-___do.__ Rating . ' (6-185) Geog. — 0. 20 N~cyclohexyl benzene sulfonamide ___________________ _. . 0 G-l4 Poor. 21 N-cyclohexyl benzene sulionamide; diphenyl sulfone _________________________________ _. _ l0 G-lO Good. 70% N -isopropylbeiizeiie sulfonamide; 30% N -isopropyl—o- and p-toluene sulionamides _______ _. 0 6-12 Fair. 0 12 G~16 (3-8 Poor. Good. 22 23 ‘ ‘ 70% N -isopropylbenzene sulfonamide; 30% N—isopropyl-o- and p-toluene sulfonamides; mixture of the o- and p-ditolyl sulfones. 24 70%are N-isogiggiyylbetizene sulfoiiamide; 30% N-isopropyl toluene sulfonamlde containing 80% 8D 0!‘ OlSOlIlEl'S. ~ 25 701%, N-isoprop(ylbenzene sulfonamide; 30% N-isopropyl toluene sulfonamide containing 80% ‘ para and 20% ortho isomers; mixture of o- and p-ditolyl sulfones. 8 G-8 Good. . _ . 2,410,635 5 . 7 ‘It is observed from the foregoing data that the compositions of the present invention are re markably stable to heat under conditions to which they are likely to be exposed in use as plasticizers and softening agents for cellulose esters, synthetic resins and protein coating com 6 4. A heat-stabilized composition comprising N-isopropyl benzene sulfonamide and from 5 to 15% of diphenyl sulfone. 5. A heat stabilized composition comprising N-isopropyl benzene sulfonamide, N-isopropyl p toluene sulfonamide and from 1 to 15% of a mixture of diphenyl sulfone and ortho- and para positions. The sulfonamides alone on the other isomers of di-tolyl sulfone. hand were all poor in stability at the temperature 6. A heat stabilized composition comprising and for the time of the test. While the compositions of the present inven 10 N~isopropyl benzene sulfonamide, N-isopropyl p toluene sulfonamide and from 5 to 15% of a, tion have been described and illustrated in the mixture of diphenyl sulfone and ortho- and para» foregoing speci?cations and examples, it is to be observed that the present invention is not to be isomers of di-tolyl sulfone. - '7. A heat -stabilized composition comprising construed as being limited in respect to any par N-isopropyl benzene sulfonamide, N-isopropyl p 15 ticular substances, proportions, conditions or toluene sulfonamide, N-isopropyl o-toluene sul combinations except as de?ned in the claims. fonamide and from 1 to 15% of a mixture of I claim: ' l. A heat-stabilized composition comprising at least one aryl sulfonamide of theformula type diphenyl sulfone, o-di-tolyl sulfone and p-di» tolyl sulfone. 8. A heat-stabilized composition comprising 20 N-isopropyl benzene sulfonamide, N-isopropyl p toluene sulfonamide, N-isopropyl o-toluene sul- ' fonamide and from 5 to 15% of a mixture of R diphenyl sulfone, o-di-tolyl sulfone and p-di in which R is a radical selected from the group 25 tolyl sulfone. 9. A heat-stabilized composition comprising consisting of hydrogen and methyl, and R’ is a 70% of N-isopropyl benzene sulfonamide, 30% radical selected from the group consisting of hy of ortho- and para-isomers of N-isopropyl tolu drogen, alkyl radicals having from 1 to 8 carbon ene sulfonamide and from 1 to 15% of a mixture atoms and cycloalkyl radicals having from 3 to 6 30 of diphenyl sulfone, o-di-tolyl sulfone and p-di carbon atoms; and from 1 to 15%, by weight of tolyl sulfone. the composition, of at least one aryl sulfone of 10. A heat-stabilized composition comprising 70% of N-isopropyl benzene sulfonamide, 30% of ortho- and para-isomers of N-isopropyl tolu the formula type R RI 0 @“U s 35 ene sulfonamide and from 5 to 15% of a mixture of diphenyl sulfone, o-di-tolyl sulfone and p-di tolyl sulfone. H o 11. A process for preparing a heat-stable com in which R and R’ are radicals selected from the group consisting of hydrogen and methyl. position comprising mixing at least one ‘aryl sul 2. A heat-stabilized composition comprising 40 fonamide of the formula type at least one aryl sulfonamide of the formula type SOzNELR’ R R 45 in which R represents a radical selected from the group consisting of hydrogen and methyl, and R’ in which R is a radical selected from the group represents a radical selected from the group con consisting of hydrogen and methyl, and R’ is a radical selected from the group consisting of 50 sisting of hydrogen, alkyl radicals having from 1 to 8 carbon atoms and cycloalkyl radicals having hydrogen, alkyl radicals having from 1 to 8 car from 3 to 6 carbon atoms; with from 1 to 15% bon atoms and cycloalkyl radicals having from 3 to 6 carbon atoms; and from 5 to 15%, by weight . of at least one aryl sulfone of the formula type of the composition, of at least one aryl sulfone R c") R’ of the formula type 55 @SU 11 o .in which R and R’ represent radicals selected from the group consisting of hydrogen and meth in which R and R’ are radicals selected from the 60 yl; heating and agitating the mixture until a homogeneous solution is formed and subsequently group consisting of hydrogen and methyl. allowing the mixture to cool. 3. A heat-stabilized composition comprising N-isopropyl benzene sulfonamide and from 1 to 15% of diphenyl sulfone. JOHN KENNETH ' CRAVER.