MXPA98004635A - Method for preparing polysulphures and organic disulfures in the presence of polystyrene-divinylbenzene (ps-dvb) resins which have guanidine or amid groups - Google Patents

Abstract

A method for achieving improved conversion rates and / or faster reaction rates, particularly in reaction (a), compared to those that can be achieved with the resins of the prior art.

Description

METHOD FOR PREPARING POLYSULPHURES AND ORGANIC DISULFIDES IN THE PRESENCE OF OLIESTIRENO-DIVINYLBENZENE (PS- DVB) RESINS WHICH HAVE GUANDIDINE OR AMIDINE GROUPS SUMMARY OF THE INVENTION A method for achieving improved conversion rates and / or faster reaction rates, particularly in reaction (a), compared to those achievable with the resins of the prior art.

FIELD OF THE INVENTION The present invention relates to the production of organic polysulphides and disulfides R-Sn-R (where n> 2) by the reaction of sulfur mercaptans, in the presence of basic resins that act as catalysts, in accordance to the reaction: basic resin 2 RSH + (n-l) S > R-Sn-R - H2S In the presence of these basic raw materials, the polysulfurcs and organic sulfur sulfur disulfides can be converted to sulfur-containing polysulfur, reacting with sulfur.

P1257 / 9S Similarly, in the presence of these same basic resins, high sulfur organic polysulfides can be converted to low sulfur polysulfides by reaction with mercaptans.

BACKGROUND OF THE INVENTION Patent application EP-A-337,837 teaches the preparation of organic polysulfides and disulfides in the presence of organic anion exchange resins containing quaternary ammonium or tertiary amine functional groups (active in the OH form. "; , generally in the form of grains or beads which are insoluble in a liquid reaction medium and, therefore, can be easily separated at the end of the reaction, allow the organic polysulfides and disulfides to be obtained by reaction of elemental sulfur with the rr. It also allows the high sulfur organic polysulphides to be obtained by reaction of the elemental sulfur with the organic sulfur-containing polysulfurides SV Luis, MI Hurguete and? Altava, Reactive & Functior-al Pclymers, 26, 1995, 75-? 3, indicate that the easy chloro-tetylacetylation of polystyrene resins and the high reactivity of the resulting beri-ciic sites allows the intreduction of a plow, number of functional groups and explains the widespread use of these polymers.

Pl257 / 98 On the other hand, these authors note that the reduced length in the methylene spacer arm reduces the mobility of the introduced functional groups and, in some cases, makes it difficult for reactants, substrates and solvents to have access to them. This situation can lead to a decrease in the activity of the functional groups when compared with their corresponding solubles. In certain cases, a marked improvement in the activity of these groups bound to the resin has been obtained when the active site is separated from the polymer backbone by a suitable spacer arm. S.V. Luis et al. they prepare polystyrene resins having spacer arms in the form of a linear aliphatic chain containing 6 or 9 methylene groups and carrying a hydroxyl group -OH at the end of the chain. This hydroxy group becomes a leaving group of tosylate, the latter being replaced by substitution with a tertiary amine group. In this synthesis, S.V. Luis et al. they use the functionalization of the polystyrene resin by a reaction of Friedel Crafts using the acid chloride derived from the ur-rioalkyl ester of an alkanedioic acid. This synthesis has the main problem of reducing both a tosylhydrazone group and an ester group by double hydrolysis (LIAH4) er-tetranidrcfuran (THF).

P12S7 / 98 This reduction makes the synthetic route not attractive in terms of the large-scale industrial development of the resins that contain these spacer arms Cg or Cg. Other authors have been interested in producing spacer arms in the form of a methylene chain. In this way, M. Tomoi, N. Kolri and H. Kakiuchi, Reactive Polymers, 3, 1985, 341-349, introduces a long aliphatic chain on the polystyrene resin by alkylation with β-bromoalkanes in the presence of trifluoromethanesulfonic acid. However, this synthesis is limited to the preparation of polymers with a spacer arm that has a low degree of crosslinking (0-4%). In the Makromol document. Chem 185, 1984, 2117-2124, M. Tomoi, Y. Kato and H. Kakiuchi, carry out the synthesis of functionalized resins with a radical comprising a bicyclic amidine: where n is an integer equal to l, 4 or /. These amidine resins (when n is 4 or ~!) Are P1257 / 98 prepared? -bromoalkyl microporous resins, which are obtained from? -bromoalkylstyrene and divinylbenzene. Similarly, in J.M.S. Puree Appl. Chem., A29 (3), pp 249-261 (1992), K. UJima, W. Fukuda, and M. Tomoi carry out the synthesis of a microporous resin functionalized with a radical comprising a bicyclic guanidine: These authors studied the activity of the above bicyclic amidine resin (n = 1) and of the above guanidine resin in the esterification of benzoic acid with 1-bromobutane in toluene or acetonitrile. These two resins have proven effective in the alkylation with 1-bromobutene of compounds that contain active methylene. Starting with a chloromethyl-polystyrene resin, 3.D. Darling and IA. Z Fréchet, J. Org. Chem., 51, 198c, 2273-2276, have obtained, for their part, ur. spacer arm - (C? ') 2 ~ ° -ue separates the resin from a hydroxyl P1257 / 98 -OH at the end of the chain. This hydroxyl is converted to tosylate and then, by a Gabriel reaction using potassium phthalimide and finally hydrazine, is converted to a primary amine. However, this synthesis has the problem of using n-butyllithium hydride or lithium aluminum hydride. The subject of this invention refers to the proposal of a process for the preparation of organic polysulfides and disulfides, according to the aforementioned reactions, in the presence of PS-DVB resins synthesized or specially selected and functionalized, in order to obtain better results than those of the prior art. These better results can, for example, refer to a better degree of conversion of the reactants and / or to a faster reaction kinetics. This objective is achieved with the use of resins functionalized with guanidine or amidine groups. More precisely, the invention proposes a process for the preparer, of polysulfides and organic disulfides by reaction of the sulfur with a mercaptanc or with ur. low sulfur content, in order to convert it into a high sulfur polysulfide or, alternatively, by reaction of a mercaptan with an organic polysulfide of altered sulfur content.

P1257 / 98 of converting it into a low sulfur polysulfide in the presence of a catalyst, in the form of a resin with a basic function, characterized in that the resin is based on polystyrene-divinylbenzene (PS-DVB) functionalized with basic groups and having the formula general (I): (? rA / / B (I) B represents a group selected from: 1. a guanidine radical of the general formula (C) N / R N (O 3 N R 4 substituted with L in the imine nitrogen, where R] _, ^ • 2 'R3 and R4' independently of each other, are selected from hydrogen. methyl, ethyl, propyl, burile, cyclohexyl and phenylc, with the condition ae aue L in this case represents P1257 / 9- a linear organic radical that is as long or longer than the methylene radical -CH2- 2.- a cyclic guanidine radical of the formula (D): substituted with L in position 7, with the proviso that L in this case represents a radical - CR2) n-, where n is an integer equal to 1 or 3 to 9, 3. - a cyclic amidine of the formula (E) : substituted with L in position 6, provided that L in this case represents a radical - (CH2) n ~, where n is an integer equal to 1 or 3 to 9, 4. - ur-a cyclic amidine of the formula ( F): PI: • 98 substituted with L in position 7, provided that L in this case represents a radical - (CH2) n-, where n is an integer equal to 1 or 3 to 9.

It is the PS-DVB resin holder. The resins which serve as starting materials for the preparation of resins of general formula (I) can be PS-DVB copolymers or chloromethyl PS-DVB copolymers. With a low content of divinylbenzene (0.5 to 7% by weight) as crosslinking agent, the gel-type copolymers can be obtained, while with higher DVB content macroreticulated resins of macroporous structure can be obtained. The DV3 content can be between 0.5% and c0% by weight relative to the total weight of the PS-DV3 copolymer. The starting materials and, er. Consequently, the resins of the general formula (I) can be of the gel type; preferably - the resins of the general formula (I * are crosslinked and have a macroporous structure to which = 1257/98 these characteristics generally entail a better catalytic activity during the process. These PS-DVB resins can be chlorinated with chloromethyl ether, according to known techniques that are described in the literature, at variable chlorine contents (Cl), in general from 1 to 20% by weight of the chlorine relative to the weight of the chloromethyl resin. Preferably, the radical L represents a methylene. This is because the resins are easy to synthesize. Advantageously, the radical L has the following general formula (II): -CH2- (X-CH2-CH2) tn- UD wherein X represents oxygen or sulfur and m is equal to or 2. Preferably, in the formula (II) , X is oxygen and m is equal to the alternative-entity X is sulfur and m is equal to l. Advantageously, the mercaptans and polydisulfides and organic disulfides have hydrocarbon radicals R selected from the alkyl, cycloalkyl, aryl, aralkyl and alkylaryl group. The present invention applies in particular to the production of dialkyl disulfurs and polysulphides containing in total from 2 to 40 carbon atoms, for example P1257 / 98 dimethyl, diethyl, dipropyl, dibutyl, dipentyl, dihexyl, diheptyl, dioctyl, didecyl and didodecyl disulfides and polysulfides. The invention also applies to the preparation of cycloalkyl disulfides and polysulfides, for example dicyclohexyl disulfide or polysulfides, or the preparation of diphenyl disulfide or polysulfides, for example. Advantageously, the hydrocarbon radical R carries one or more functional groups. These groups are, for example, halogen atoms, -OH, -OR1, -SR ', -NR' R ", * CN, .CHO, -COR 'and -COOR', R 'and R" denote aliphatic radicals. C to C 2 ° cycloaliphatic, aromatic or alkylaromatic radicals. The catalytic activity of the resins used in the invention is revealed at very low resin contents in the mixtures. Advantageously, the resin is present in an amount ranging from 0.01 to 20 parts by weight per 100 parts by weight of the reaction mixture, including resin. The process of compliance with the invention utilizes a reaction that can be carried out at a temperature of from -10 ° C to 150 ° C. Preferably, the temperature is from -10 ° C to 120 ° C. The reactions can be carried out at atmospheric pressure or at higher pressures that can reach 50 P1257 / 9S Pub. In general, this pressure is 28 bar absolute. In the case of relatively non-volatile reactants with low vapor pressure, the reaction can be carried out at pressures below atmospheric pressure, optionally in the presence of an inert gas, such as for example nitrogen. The molar ratio of mercaptan / sulfur depends on the nature of the mercaptan used and the product to be prepared (disulfide or polysulfide). Advantageously, this proportion is from 0.3 to 10, and preferably from 0.4 to 6. In the case where an organic polysulfide with higher order of sulfur has been used at the beginning, which one wishes to convert into organic polysulfide with order of sulfur low, for example in trisulfide R-S3-R or disulfide R-S2- by the action of the corresponding mercaptan, advantageously, a molar ratio of mercaptan / polysulfide ranging from 2 to 10 is used. The production of disulfides or polysulphides in the presence of PS-DVB resins with a guanidine or amidine function can be carried out in a stirred or tubular reactor, in accordance with a batch process or by loading the reactants before reacting them or by the gradual addition of one of the reactants or, by the simultaneous addition of the reactants to the reactor or, alternatively in accordance with a continuous process P1257 / 98 with the controlled addition of the reactants. In the case where the sulfur is one of the reactants (the other is a mercaptan or a polysulfide of lower order of sulfur) it can be introduced in liquid or solid form. Resins of general formula (I) can be obtained or prepared in the following way: 1. Group B is a radical of general formula (C). The process of replacing the chlorine of a chloromethyl polystyrene-divinylbenzene resin with a substituted or unsubstituted guanidine is known from U.S. Patent 5,340,380, this process makes it possible to obtain resins of the general formula (I.C): represent the initial solid resin support of pclistyrene-divinylbenzene, it is possible that R? _, ^ 2 r P > 3 R4 are each a hydrogen, an alkyl group or an aromatic group.

P1257 / 98 Thus, US Pat. No. 3,346,516 describes this functionalization technique by reacting a chloromethyl polystyrene-divinylbenzene resin with guanidine or tetramethylguanidine in the presence of a lower alcohol and a solvent for swelling the polymer, such as can be , tetrahydrofuran, dioxane or diglyme. In U.S. Patent 5,028,259, tetramethylguanidine is contacted with a chloromethyl polystyrene-io-divinylbenzene resin in a mixture of toluene and tetrahydrofuran. In U.S. Patent 5,340,380, the guanidines are reacted with chloromethyl resins of this same type in the presence of sodium hydroxide in a solvent consisting of ethanol or water. However, this technique of functionalization of the chloromethyl PS-DVB resin with a guanidine in practice is very limited for the production of resins with formula (? .C) in which the guanidine radicals carry the substituents] _ to R ? different from four methyl or four hydrogens, until now since only guanidine and 1, 1, 3,? -tetramethylguanidine are currently commercial. These reams (I.C. in which the groups R-_ to R4 are all different from hydrogen can be obtained P1257 / 98 using tetrasubstituted ureas which are frequently marketed under the following preparation conditions: a) to prepare a PS-DVB resin functionalized with primary amine groups and having the general formula (A).

These can be obtained by several techniques: 1. It is possible, for example, to start with a resin of general formula (J): // (J) X is a leaving group, in particular, halogen or tosylate which can be obtained from a hydroxyl group -OH, and L has the same meaning as above, in particular, a radical - (CH2) Q-, where p is an integer from 1 to 9, including 2. Preferably, when L represents a single P1257 / 98 methylene, X is a chlorine atom. In this case, a method, described by D.H. Rich and S.K. Gurwara, J. Am. Chem. Soc., 1975, 97-1575-1579, consists in reacting a chloromethyl PS-DVB resin with an excess of ammonia. Another route is based on the production of phthalimidomethyl PS-DVB resin, which is converted by hydrazinolysis into a resin with a primary amine function. The two methods for obtaining access to these phthalimidomethyl resins are described in the publication of A.R. Mitchell, S.B.H. Kent, B. Erickson and R.B. Merrifield, Tetrahedron Letters No. 42, 1976, 3795-3798. One is to start with a PS-DVB resin which, when reacted with N- (chloromethyl) phthalimide, is converted directly to phthalimidomethyl resin. The other method begins with a chloromethyl PS-DVB resin which is treated with potassium phthalimide to provide the corresponding phthalimidomethyl resin. A few PS-DV3 resins with a primary amine function of formula (A) in which L represents a methylene are commercial. In this way, the company Purolite proposes two macro-crescent resins, the A-107 and the A-109, while the company Fluka has, in its 1995-1996 catalog, two gel resins: resin 08564 PS retted with 2% of DV3 and containing 1.1 -r-moles ae groups --.--- 2 per gram of resin and, P12S7 / 98 resin 08566 PS crosslinked with 1% DVB and containing 0.6 mmoles of - H2 per gram of resin. The potassium phthalimide method can also be applied to the resins of formula (J) in the case where L is a linear organic radical longer than the methylene radical, in particular - (CH2) n- 'where n is a number greater than 1. 2. It is also possible to start with a PS-DVB resin of formula (J) in which L represents a methylene and X has the above meaning and preferably represents a chlorine atom. The Applicant has found that this chloromethyl resin can be reacted with an alkanolamine or a mercaptoalkylamine, in the form of an alkaline alkoxide, under illiamson reaction conditions. If ethanolamine is used, resins are obtained PS-DVB having a primary amine function with functional groups -CH2-O- H2-CH2-NH2 attached to the resin supports of PS-DVB. Similarly, starting with 2-aminoethanethiol hydrochloride, functional groups -CH 2 -S-CH 2 -CH 2 -NH 2 are obtained. If 2- (2-aminoethoxy) ethanol is used, PS-DVB resins having a primary amine function with functional groups -CH2 (0-CHr-2H2) 2-N ^ 2 are obtained.

P1257 / 98 Finally, using 2 - [(2-aminoethyl) thio] ethanethiol, functional groups -CH2- (S-CH2-CH2) 2-NH are obtained. This initial mercaptoalkylamine can be prepared according to Iwakura et al., J. Polym. Sci. Part A, 2, 1964, 881-883 or, in accordance with I. Voronkov, M.G. et al., Chem. Heterocycl. Compd. (Engl. Transí.) 15, 1979, 1183-1185. The general conditions of the illiamson reaction are as follows: The alkanolamine or the mercaptoalkylamine diluted in anhydrous tetrahydrofuran (THF) is reacted with sodium hydride suspended in anhydrous THF. After the formation of sodium alkoxide or sodium mercaptide, the chloromethyl resin is introduced into the liquid reaction medium. b) after the resin having primary amine groups of general formula (A) is obtained, these groups are reacted with chloroforr.amidinium chloride (Vilsmeier salt) of general formula (H): P12S7 / 98 -R? N H) Cl Cl (, R. N * R wherein R ^, R2, R3 and R4 are, independently of one another, selected from methyl, ethyl, propyl, butyl, cyclohexyl and phenyl groups, to obtain a PS-DVB resin functionalized with a guanidine group and of general formula (I.C): N R 4 AT \ = ^, and R to R4 have the same meanings as above. Chloroformamidinium chlorides (H) are generally obtained from tetrasubstituted ureas by reaction with electrophilic compounds such as phosgene, thionyl chloride, oxalyl chloride or phosphorus oxychloride, in accordance with the methods described in the literature, in particular: P1257 / 98 COCI2 H. Eilingsfeld, M. Seefelder, Angew. Chem., 72, 1960, 836. S0C12 H. Ulrich, A.A.R. Sayigh, Angew. Chem. Intern. Ed. Engl., 5, 1966, 704. (COCÍ) 2 T. Fujisawa et al., Chem. Lett., 1982, 1891.

POCI3 H. Bredereck, K. Bredereck, Chem. Ber., 94, 1961, 2278. Generally, electrophiles are initially used stoichiometric amounts of tetrasubstituted ureas and chlorine compounds and the process is carried out in the presence of a solvent such as tetrachloride of carbon in the case of oxalyl chloride or without solvent with phosgene or thionyl chloride at a temperature generally of from 0 ° C to 40 ° C and, under an anhydrous atmosphere to prevent hydrolysis. The tetrasubstituted ureas are advantageously selected from tetramethylurea, tetraethylurea, tetra-n-propylurea and tetra-butylurea. The chloroformamidinium chlorides (H) are generally placed in a solvent such as toluene or acetonitrile. Their reactions with the resins containing a primary amine function (A) are carried out in the presence of a base, preferably in the presence of an excess of base. If the base is triethylamide (TEA), the processes P1257 / 98 they are generally carried out or carried out with a molar excess of TEA of from 10 to 50% with respect to chloroformamidinium chlorides (H). The latter are generally in a molar excess of from 10 to 100% icon with respect to the number of moles of the primary amine function, in order to convert all of the latter to functions of -guanidine. 2. Group B is a radical of general formula (D). (a) To begin with, a resin of general formula (J) was prepared as in point 1. a) above, L represents a radical - (CH2) n ~ - n is an integer equal to 1 or 3 to 9 and X is chlorine or bromine. (b) The above halogenated resin is reacted with 1, 5, 7-triazabicyclo [4.4.0] dec-5-ene (TBD), in a manner similar to the M. Tomoi process. et al, J.M.S. Puree Appl. Chem. A29 (3), 1992, 249-261, in particular page 251 ("Preparation of Polystyrene-Supported TBD)." In this way, a PS-DVB resin is obtained which is functionalized with a bicyclic guanidine group of general formula (ID.: P1257 / 98 L represents a radical ~ (CH2) n_ where n is an integer equal to 1 or 3 to 9. 3. Group B is a radical of general formula (E). a) The resin of general formula (J), as in point 2. a) above, is prepared to begin. b) The halogenated resin obtained above is reacted with 1,8-diazabicyclo [5. .0] undec-7-ene (DBU) in a manner similar to the process of M. Tomoi et al., Makromol. Chem, 185, 1984, 2117-2124, in particular page 2118, "Preparation of polystyrene-supported DBU." In this way, a PS-DVB resin is obtained which is functionalized with a bicyclic amidine group of general formula (IE) : P12S7 / 98 L represents a radical - (CH2) n where n is an integer equal to 1 or 3 to 9. Group B is a radical of general formula (F). The process is performed as in 2. a) and 2. b) with the exception that the DBU is replaced by 1,5-diazabicyclo [4.3.0] -non-5-ene (DBN). In this way, a PS-DVB resin functionalized with a bicyclic amidine group of general formula (I.F.) is obtained: L represents a radical - (CH2) n where n is an integer equal to 1 or 3 to 9. The catalytic efficiency of the resins used in the present invention was found to improve when dry. The catalytic activity of the gel-type resins used in the present invention is greatly improved by the presence of methane in the reaction mixtures, as reported in the preamble of the P12S7 / 98 Claim 1 of the process. This methanol promoting effect (also observed with ethanol but, to a lesser degree) is detected at low contents and above these low contents in the reaction mixtures, for amounts of methanol varying from 0.01 g to 2 g per 100 g of reaction mixture comprising resin, sulfur, mercaptan and methanol or sulfur resin, polysulfide and methanol or, alternatively, resin, mercaptan, polysulfide and methanol. In this way, the methanol is advantageously added to the reaction medium. In addition to the foregoing description, the present invention will be better understood with the help of the following experimental section for illustrative purposes.

Experimental Section The resins are dried in a vacuum of approximately 4.xl0 ^ pascals (Pa). 1. Production of PS-DVB resins of formula (I.C) containing function 1, 1,3,3-tetramethylguanidine The technique used consists in directly incorporating the TMG into a chloromethyl PS-DVB resin, in accordance with the method described in the patents of the United States of America 3,345,516 and P1257 / 98 ,028,259. Two types of chloromethyl PS-DVB resins were used: a) a gel-like resin: Bio-Beeds »SSX1, based on 1% PS crosslinked with DVB and chloromethylated with a chlorine content of 11.52% by weight with respect to to the total weight. Thus, this resin contains 4.09 mmoles of Cl / g of resin. b) a macroporous type resin having the following characteristics: Specific surface: 22.5 m ^ / g of resin Average pore diameter: 20 Á Pore volume: 69% chloromethylated with a chlorine content of 19.32% by weight with respect to total weight. In this way, the resin contains 5.44 meq Cl / g resin.

Procedure: A certain amount of dry chloromethyl resin containing 0.3544 moles of Cl (ie, 13.3 g of resin 1. a) and 10 g of resin 1. b)) was weighed and brought into contact, under an atmosphere of nitrogen, with 12.5 g (3.1088) of TMG diluted in 120 ml of tetrahydrofuran (THF) pre-dried on molecular sieve.

P1257 / 98 obtained is mechanically stirred for 48 hours at a temperature of 60 ° C. After cooling to 20 ° C, the resin is filtered and washed with THF, then with 200 ml of 10% aqueous sodium hydroxide solution and finally with water until neutral. The resin is washed with acetone and then dried under vacuum at 60 ° C to constant weight. The elemental analysis was carried out on two resins obtained in this way. For the resin of the a) gel type referred to below as No. 1 (TMG), N = 7.85% by weight, that is, 1.87 mmole of TMG / g of resin. For the resin of b) of the macropore type referred to below as No. 2 (TMG), N = 8.74% by weight, ie 2.08 mmole of TMG / g of resin. 2. The production of PS-DVB resins of formula (I.C) containing a TMG function (L = -CH2-O-CH2-CH2-, R = R2 = 3 = R4 = -CH3). The two resins of a) and b) above were used. a, Preparation of sodium aminoethoxide ÍNaO- (CH2) 2 ~ - ^ 2) • A solution of 2.5 ml of ethanolamine in 25 ml of Anhydrous THF (freshly distilled over sodium) is added slowly, under a nitrogen atmosphere, to a solution of 1.5 g of sodium hydride dissolved in 40 ml of anhydrous THF. The reaction medium is maintained in PL2S7 / 98 stirring at a temperature of 20 ° C for 1 hour and then maintained under reflux for 2 hours. The sodium aminoethoxide solution is then cooled to 20 ° C and maintained under a nitrogen atmosphere. b) Production of resins of general formula (A) containing a primary amine function, wherein L represents -CH 2 -O-CH 2 -CH 2 -; A certain amount of the above dry chloromethyl resin 1. a) is selected which contains 0.0272 moles of chlorine, ie 6.65 g. The same selection is made with dry chloromethyl resin 1. b) based on 0.0272 moles of chlorine, that is, 5 g. Each of these resins is treated separately as follows: The selected resin (6.65 or 5 g) is introduced into an aminoethoxide solution prepared in accordance with 2.a). The medium is kept under stirring at 70 ° C for 48 hours. After cooling to approximately 20 ° C, the resin is recovered. It is washed with water, then with 5% by weight aqueous potassium hydroxide solution and then with water until neutral. the wet resin is washed with methane! and, finally, they are dried in a vacuum at 60 ° C.

P1257 / 98 c) Preparation of tetramethylchloroformamidinium chloride. A solution of 2.5 ml (0.027 mol) of oxalyl chloride in 15 ml of anhydrous carbon tetrachloride is poured dropwise into a solution of 3.4 ml (0.027 mol) of tetramethylurea in 10 ml of anhydrous carbon tetrachloride is maintained under stirring in an atmosphere of nitrogen. While stirring is continued, the reaction medium is refluxed until the evolution of carbon dioxide and gaseous carbon monoxide ceases. The formamidinium chloride obtained as a white solid is dissolved at 0 ° C in 30 ml of anhydrous acetonitrile. d) Reaction with the previous resins containing a primary amine function (L = CH2-O-CH2-CH2-) • For each of the two previous resins, 5 g of the resin was suspended with stirring and at a temperature of 0 ° C , in a mixture of 5.2 ml (0.0374 mol 'of triethylamine and 20 ml of anhydrous acetonitrile.) The solution of chlamydidium chloride in 30 ml of anhydrous acetonitrile obtained above is slowly added to this suspension kept at 0 ° C. The mixture is stirred for 72 hours at a temperature of 20 = Z and then refluxed for 1 hour, after cooling to 20 ° C, the resin is filtered and washed with water, then with hydroxide solution.

P1257 / 98 sodium at 10% by weight and again with water until neutrality. The wet resin is washed with methanol, then with acetone and finally dried under vacuum at 60 ° C. The elemental analysis was carried out on the two resins thus obtained and the number of moles of guanidine functions inserted was calculated: - for the gel-type resin obtained from 1. a): N = 9.03%, that is 2.15 mmoles of tetramethylguanidine ( -TMG) / g of resin, referred to below as No. 3 (-TMG). for the macroporous type resin obtained in 1. b): N = 6.98%, that is, 1.66 mmoles of tetramethylguanidine (-TMG) / g of resin, referred to below as No. 4 (-TMG). 3. The production of PS-DVB resins of formula (IC) containing a function of 1, 1, 3, 3-tetra-n-butylguani ina (TBG) (L = -CH2-, Rl = R2 = R3 = R4 = n-butyl). The preparation technique used consists of starting with a non-functionalized PS-DVB resin. This copclimer is functionalized in a first step, in a reaminomethyl "function -CH2-H2" in accordance with the method described in Tetrahedron Letters or. 42, 1976, 3795-3798. The resin obtained P12S7 / 98 it is then functionalized in a resin containing a 1,1,3,3-tetra-n-butylguanidine function utilizing tetra-n-butylchloroformamidinium chloride. The PS-DVB resin used is a porous synthetic copolymer manufactured by Rohm and Haas, Amberlite XAD-4. The characteristics of this highly cross-linked resin, provided by Rohm and Haas, are: Specific surface area: 750 m ^ / g of resin Average pore diameter: 50 A Pore volume: 51% a) Functionalization of the Amberlite XAD-4 resin in phthalimidomethyl resin. 10 g of pre-dried Amberlite XAD-4 resin was suspended in a solution of 0.5 ml (0.0043 mol) of tin tetrachloride in 30 ml of 1,2-dichloroethane. To this suspension were added 6.7 g (0.0342 mol) of N-chloromethylphthalimide dissolved in 20 ml of 1,2-dichloroethane with stirring and at 60 ° C. The reaction medium was kept under reflux (82-84 ° C) with stirring for 5 hours. After cooling to room temperature (20 ° C), the resin was filtered and then washed with dichloromethane and finally with methanol. After drying at 60 ° C under vacuum, 13.1 g of resin was obtained.

P1257 / 98 IR spectrum:? (CO-N-CO) and d (CO-N-CO) at 1770 cm ~ 1 and 1710 cm "1. b) Hydrazinolysis to produce the primary amine function 4.5 ml (0.092 mol) of hydrazine hydrate and 0.9 g ( 0.022 mol) of sodium hydroxide lentils were added, with stirring, to a suspension of 12 g of the resin obtained in 3. a) in 40 ml of absolute ethanol.The reaction medium is then kept under reflux for 48 hours. After cooling to 20 ° C, the resin is filtered and washed with ethanol and then with 5% by weight aqueous potassium hydroxide solution.The resin is then washed with water until neutral, with ethanol, with acetone and, Finally, it is dried under vacuum at 60 ° C to provide 11 g of resin.This resin no longer shows the characteristic bands of the phthalimide in the IR An elemental analysis was carried out: N = 3.53%, that is, 2.52 mmoles of - H2 / g of resin c Fupcionalization of this aminomethyl resin in a tetra-n-butylguanidine function. tra-n-butylchlorofornamidinium was prepared by bubbling 5.5 g of phosgene into 10.4 g .0.037 P12S7 / 98 mmol) of tetra-n-butylurea in 2 hours, with stirring and at a temperature of 80 ° C for 5 hours. The excess phosgene was then removed by evaporation in vacuo. 12.45 g of tetra-n-butylchloroformamide chloride were obtained as a white solid. This chloride is dissolved in 40 ml of anhydrous acetonitrile. To this stirred chloride solution were added 10 g of the aminomethyl resin and 8.7 ml (0.0625 mol) of triethylamine, under a nitrogen atmosphere and a 0 ° C. The reaction mixture is kept under stirring at 20 ° C for 96 hours and then refluxed for 1 hour. After cooling to 20 ° C, the resin is filtered and washed with acetonitrile and then with 10% by weight aqueous sodium hydroxide solution. It is then washed with water until neutral, with acetone, with methanol and again with acetone. Dry under vacuum at 60 ° C to provide 11.3 g of resin. An elemental analysis was carried out: N = 4.62%, that is, 1.1 mmoles of guanidine (-T3G) / g of resin. This resin is referred to below as No. 1 (-TBG). 4. Production of PS-3V3 resin of formula (I.D) that P1257 / 98 it contains a function 1, 5, 7-triazabicyclo [.4.0] dec-5- ene (TBD) with L = -CH2-. The process used is described in J. Macromol. • Sci. Mashed potatoes. Appl. Chem A29 (3) 1992, 249-263. It consists in reacting the lithium salt of 1, 5, 7-triazabicyclo [4.4.0] dec-5-ene with a chloromethyl PS-DVB resin. a) Preparation of the lithium salt of TBD. 0.052 moles of n-butyllithium in 25 ml of hexane were added to a mixture of 7.9 g (0.057 mol) of TBD and 250 ml of anhydrous THF, at a temperature of -78 ° C and under an argon atmosphere. The reaction medium was then stirred at -78 ° C for 2 hours. b) Production of resins (I.D) that contain a TBD function. A certain amount of chloromethyl resin corresponding to 0.0544 mole of chlorine (ie, 13.3 g of the gel-type resin of 1.a) or 10 g of the macroporous-type resin of l.b) is weighed. This amount is added slowly in an argon atmosphere to the solution of the lithium salt of TBD maintained at -78 ° C. The reaction mixture is then gradually heated to 20 ° with stirring and held under these conditions for 70 hours. Then P1257 / 98 add 30 ml of methanol and the resin is filtered in a sintered funnel. It is washed successively with 1/1 by volume of THF / methanol mixture, then with methanol, with a mixture of 1/1 by volume of methanol / water, with acetone, with THF and with dichloromethane. The resin is dried under vacuum at 60 ° C. The elemental analysis of the two resins thus obtained was carried out. Gel type resin: N = 11.88%, that is, 2.83 mmoles of TBD / g resin function. This resin will be referred to later as No. 1 (-TBD). Macroporous type resin: N = 11.29%, that is, 2.69 mmoles of TBD / g resin function. This resin will be referred to later as No. 2 (-T3D).

EXAMPLE 1 Production of di-n-butyl disulfide by the reaction of n-butyl mercaptan with sulfur. The tests for the production of di-n-butii disulfide were carried out under identical experimental conditions using resins containing a functional P1257 / 98 guanidine (TMG) or that contain a bicyclic guanidine (TBD) function. A commercial Fluka resin, containing a TBD function, L = -CH2-: No. 90603 from the Fluka 1995/96 PS cross-linked with 2% DVB TBD: 2.8 mmoles of TBD / g dry resin was also used. Comparative tests were also carried out using a macroporous PS-DVB resin containing a tertiary amine function, L = -CH2-, the Amberlyst A-21 resin manufactured by the company Rohm and Haas. Characteristics of the resin Amberlyst A-21: Specific surface: 39.8 m ^ / g of resin functionalized with -CH2- (CH3) 2: 4.4 mmoles of tertiary amine function / g of dry resin. The tests were carried out in a reactor consisting of ur. 50 ml two-neck glass conical flask adapted with a water-cooled condenser and a thermometer sleeve to measure the temperature of the reaction medium. This reactor was heated in an oil bath placed on the plate of a hot plate magnetic stirrer. The stirring was obtained in the reaction by means of a magnetic stirring bar coated with Teflon.

P12S7 / 98 Procedure: 26.58 g (0.295 mol) of n-butyl mercaptan, 4.5 g (0.147 mol) of finely ground solid sulfur and 0.1 g of dry resin were introduced into the reactor. The reaction medium was brought to 60 ° C with stirring. After the total disappearance of the solid sulfur (generally after 15 min.), Samples were taken from the liquid reaction medium at determined times. These samples were analyzed by gas chromatography on a 50 m long capillary column Hewlett-Packard Ultra-1 to determine the disulfide weight content of di-n-butyl (S2%) formed as a function of time in minutes. In the case of tests performed in the presence of methanol, the amount of methanol incorporated in the reaction mixture is 0.4 g (0.0125 mol). The results are presented in Tables I and II below.

P1257 / 98 TABLE I RESINS CONTAINING A FUNCTION 1, 1, 3, 3 -TETRAMETILGUANIDINE (-TMG) -? * Comparative Test TABLE II RESINS CONTAINING A FUNCTION 1, 5, 7 -TRIAZABICICLO [4.4.0] DEC- 5 -ENO (-TBD) ? oo d = Total disappearance d < 1 solid sulfur after 40 min. * Comparative test These tables show that the process according to the present invention leads to better results than in the prior art.

EXAMPLE 2 Production of di-tert-butyl polysulfides by reaction of tert-butyl mercaptan with sulfur. Tests for the production of polysulfides that started with tert-butyl mercaptan and sulfur were carried out in the presence of resins and, optionally, methanol. A comparative test was carried out with Amberlyst A-21 resin.

Procedure: These tests were carried out in the same apparatus as in Example 1, under the following identical conditions: 26.5 g (0.294 mol) of tert-butyl mercaptan were introduced, with 18 g (0.56 mol) of finely ground sulfur, into the reactor with stirring and the reaction medium was brought to 60 ° C. The time for the total disappearance of the sulfur was noted. After reacting for 90 minutes, a first sample was withdrawn from the liquid reaction medium, followed by other successive extractions in the course of time. The samples were analyzed by gas chromatography on a 50 m long capillary column Hewlett-Packard Ultra-1, to determine its residual content of ter-butyl mercaptan, which represents the conversion rate of this mercaptan in the corresponding polysulfides. Table III below shows the results of these tests, which provide, for each resin tested, the time after which all the solid sulfur disappeared and the content of tert-butyl mercaptan (% of TMB by weight) remains in the reaction medium. . In the case of tests carried out in the presence of methanol, the amount of this alcohol incorporated in the reaction medium is 0.4 g (0.0125 mol).

P12S7 / 98 TABLE III H1 * Comparative test It is noted that the results of the process according to the invention are better than those of the prior art.

EXAMPLE 3 Production of di-tert-butyl trisulfide by retro-addition with ter-butyl Mercaptan di-di-buil Polysulfides of Order of Superior Sulfur. The di-tert-butyl polysulfide used has an average molar mass of 250, a sulfur content of 54.4% and a content of di-tert-butyl trisulfide, determined by gas chromatography, in a capillary column of 50 m of Hewlett-Packard Ultra-1, of 29.5%, the rest consisted of polysulfides of order of superior sulfur. Tests for the retrogradation of the polysulfides (S x with x> 3) by terbutyl mercaptan were carried out in the presence of different guanidine resins, optionally in the presence of methanol. A comparative test was carried out with the resin A-21. All the tests were carried out in an apparatus identical to the one described above.

P1..S7 / 98 Procedure: 10 g (0.0365 mol) of di-tert-butyl polysulfide, 19.71 g (0.219 mol) of tert-butyl mercaptan and 0.5 g of the chosen resin were introduced into the reactor. The reaction medium was rapidly brought to a temperature of 60 ° C with stirring. At determined time intervals samples were taken and analyzed by gas chromatography on a 50 m long capillary column Hewlett-Packard Ultra-1. The chromatographic monitoring makes it possible to determine the content of di-tert-butyl trisulfide formed over time. In the case of tests performed in the presence of methanol, the amount of this alcohol incorporated in the reaction medium is 0.4 g (0.0125 mol). The results of the tests with the different resins tested are presented in Tables IV, V and VI, below, which provide, for each resin tested, the proportion by weight of di-tert-butyl trisulfide (S3%) formed as a function of time in minutes.

P1257 / 98 TABLE IV GEL-TYPE RESINS CONTAINING A GUANIDINE FUNCTION (METHANOL TESTS) Comparative test TABLE V MACROPOROSE TYPE RESINS CONTAINING A GUANIDINE FUNCTION (METHANOL TESTS) * Comparative test TABLE VI MACROPOROSE TYPE RESINS CONTAINING A GUANIDINE FUNCTION (TESTS WITHOUT METHANOL) * Comparative test

Claims (13)

NOVELTY OF THE INVENTION Having described the present invention, it is considered as a novelty and, therefore, the content of the following CLAIMS is claimed as property: 1. Process for the preparation of organic disulfides and polysulfides by the reaction of sulfur with a mercaptan or with a polysulfide of lower order of sulfur, in order to convert it into polysulfide of higher order or, alternatively, by the reaction of a mercaptan with an organic polysulfide of high order of sulfur in order to convert it into a polysulfide of the order of lower sulfur, in the presence of a catalyst in the form of a resin with a basic function, characterized in that the resin is based on polystyrene-divinylbenzene (PS-DVB), functionalized with basic groups and having the general formula (I): where 3 represents a group selected from:

1. - a guanidine radical of general formula (C) P1257 / 98 N / R N = C 2 (C) N substituted with L in the nitrogen of the imine, in which R? _, R2, R3 and R4 are selected, independently of one another, from hydrogen and methyl, ethyl, propyl, butyl, cyclohexyl and phenyl groups, with the proviso that that L, in this case, represents a linear organic radical that is as long as or longer than the methylene radical -CH 2 -, 2. - a cyclic guanidine radical of formula (D): substituted with L in position 7, with the proviso that L in this case represents a radical - (CH2) n- 'n is an integer equal to 1 or from 3 to 9, 3. - a cyclic amidine of formula (E) ): P1257 / 98 substituted with L in position 6, with the proviso that L in this case represents a radical - (CH2) n ~. n is an integer equal to 1 or from 3 to 9, 4. - a cyclic amidine of formula (F): substituted with L in position 7, with the proviso that L in this case represents a radical - (CH2) n- 'n is an integer equal to 1 or 3 to 9 It is the resin holder of PS-DVB.

2. The process according to claim 1, characterized in that the resin of the general formula (I) is of the gel type.

3. The process according to claim 1, characterized in that the resin of the general formula (I) is macro-crosslinked and has a macroporous structure. P12S7 / 98

4. The process according to any of claims 1 to 3, characterized in that L represents a methylene (-CH2-) -

5. The process according to any of claims 1 to 3, characterized in that when L is attached to the guanidine radical of formula (C) ) represents a radical of formula (II). -CH2- (X-CH2-CH2) m- (ID X represents oxygen (-0-) or sulfur (-S-) and m is equal to 1 or 2.

6. The process according to claim 5, characterized in that X represents oxygen and because m equals 1. The process according to claim 5, characterized in that X represents sulfur and m equals 1. 8. The process according to any of claims 1 to 7, characterized in that the mercaptans and the disulfides and organic polysulfides have hydrocarbon radicals R selected from an alkyl, cycloalkyl, aryl or aralkyl group 9. The process according to claim 8, characterized in that the radical R carries one or more functional groups 10. The process according to any of claims 1 to 9, characterized in that the resin is P1257 / 98 present in an amount ranging from 0.01 to 20 parts by weight per 100 parts by weight of the reaction mixture, including the resin. 11. The process according to any of claims 1 to 10, characterized in that the reaction is carried out at a temperature of from -10 ° C to 150 ° C. 12. The process according to claim 11, characterized in that the temperature is from + 10 ° C to 120 ° C. The process according to any of claims 1 to 12, characterized in that the methanol is added to the reaction medium. P12S7 / 98