3,438,959 United States Patent Office Patented Apr. 15, 1969 2 al pulping liquors which have been altered somewhat by 3,438,959 further processing or treatment such as an acid treatment, LGNOSULFONATE DERVATIVE AND A PROCESS FOR ITS PREPARATION alkaline treatment, heat treatment, oxidation with acids Chung Su Youn Kim, Belingham, Wash., assignor to as well as other oxidizing agents, and other treatments Georgia-Pacific Corporation, Portland, Oreg, a cor are operative as long as the lignin constituents retain poration of Georgia their basic phenylpropane polymeric structure to have No Drawing. Filed Oct. 1, 1965, Ser. No. 492,262 the general porperties and characteristics associated with Int. C. C07g 1/00; C11d 1/30 the lignin products. U.S. C. 260- 124 20 Cains In the separation of lignin from the lignocellulosic ma terials, other constituents besides lignin are generally ob O tained in the lignin-containing product. For example, ABSTRACT OF THE DISCLOSURE spent sulfite liquor generally contains about 40 to 60 The preparation of a halogenated lignosulfonate by weight percent of lignosulfonate with the remainder be the reaction of lignosulfonate with thionyl chloride or ing carbohydrates and other organic and inorganic ma thionyl bromide under substantially anhydrous conditions. terials dissolved in the liquor. Lignin products obtained by other processes will likewise contain other materials such as carbohydrates, degradation products of carbohy This invention relates to a derivative of lignosulfonate drates, and resinous materials which may remain after and particularly to a halogen containing derivative of sulfonation of the lignin products obtained by Such proc lignoSulfonate and a process for its preparation. esses. Most of the non-lignin constituents such as Sugars Lignin is a polymeric Substance found in plant and may not be detrimental but will result in the utilization vegetable tissue associated with cellulose and other plant of the thionyl halide by reacting with the reagent. Thus, constituents. In the pulp and paper industry, lignin-con generally the lignosulfonate constituents are separated taining materials such as wood, straw, corn Stalks, ba from the non-lignin products prior to reaction with the gasse, and other vegetable and plant tissues are processed acid halide. Lignin products such as a Sulfonated residual to recover the cellulose or pulp with lignin being obtained pulping liquor may be subjected to different treatments, as a by-product. Since vegetable and plant tissues can such as, for example, acid, alkaline or heat treatments contain up to about 30% lignin, large amounts of lignin as well as reaction with other chemicals or oxidation to are available. Considerable effort has been expended in remove or modify some of the non-lignin constituents or lignin research without too much success in the develop for other purposes. The lignin constituents may be af ment of methods or processes to utilize more fully the fected to a certain extent by such treatments but this is chemical values of lignin. Lignin and lignosulfonates not detrimental as long as the treatment is not so Severe have found only limited markets resulting in an appreci as to destroy the basic phenylpropane polymeric struc able amount of the pulping liquors having to be processed ture of the lignin and properties characteristic of these mainly for disposal purposes rather than for recovery of products. For example, a spent sulfite liquor may be oxi any chemical values. dized as in the preparation of vanillin. The vanillin raf It is therefore an object of this invention to provide finate obtained will generally contain lignosulfonates a process for the treatment of residual pulping liquors which may be altered somewhat but which still retain the or lignin so that the chemical value of the product can basic properties and characteristics associated with ligno be utilized. A further object is to provide a lignin deriva 40 sulfonates. It is generally preferred to recover the ligno tive product which is reactive and can be used as an in sulfonates from the lignin products by solvent extraction termediate in the formation of other chemical products. or by precipitation with an alkaline earth hydroxide, an The above and other objects are attained by interacting acid, or an amine. Other known methods, however, may sulfonated lignin with a thionyl halide selected from the also be used, some of which are ion exchange, dialysis group consisting of thionyl chloride and thionyl bromide. and electrodialysis. The interaction of the sulfonated lignin with the thionyl In addition to recovery of the lignosulfonates, the re halide will result in the formation of a halogen contain covered lignosulfonates may be further treated to reduce ing derivative which is reactive and may be reacted with the average molecular weight of the product. The igno other chemicals to form different products. For example, sulfonate having average molecular weights in the range the intermediate product may be interacted with an alco such that the diffusion coefficient is in the range of 14 to holate or a phenolate to form esters or with an amine 20 mm.2/day (as determined by the agar gel method de to form lignosulfonamides. scribed in J. Am. Chem. Soc. vol. 81, 2054 by J. Moacanin It is essential that the lignin be sulfonated prior to re et al.) result in the preparation of a more reactive inter action with the thionyl halide. In some of the pulping mediate product. If desired, the lignosulfonate product processes, for example, the sulfite pulping process, the may be fractionated to recover the low molecular weight residual pulping liquor is a sulfonated product containing fraction. However, it is generally preferred to treat the the lignin in a sulfonated form. In other processes, the lignosulfonate obtained to reduce the average molecular residual pulping liquor or the lignin-containing product weight. This may be done by using the various known as obtained from the process may not be a Sulfonated methods, for example, prehalogenation of the lignosulfo product. However, the residual liquors or products con 60 nate or resulfonation under conditions to obtain reduced taining the lignin portion may be sulfonated by various molecular weight. In the prehalogenation, halogen gases known methods to the degree desired by reaction, for Such as chlorine or bromine may be used or other halo example, with a bisulfite or sulfite, including further Sul genating agents employed which result in the formation of fonation of a sulfite pulping liquor. Residual pulping elemental bromine or chlorine under the treatment condi liquors obtained in the Kraft and other alkaline processes tions. In addition to just reducing the molecular weight, of digestion of lignocellulosic materials, “hydrolysis the prehalogenation results in halogenating the sulfonated lignin’ obtained by the hydrolysis of lignocellulosic ma ignin which has an advantageous effect in making the terials in the manufacture of wood Sugars, “hydrotropic product react more rapidly and efficiently with the thiony lignins' derived from hydrotropic pulping processes, or halide. Halogen Substitution on the aromatic groups of lignin obtained from any source may thus be sulfonated 70 the lignin is most likely obtained by the prehalogenation and used in the formation of the reactive halogenated resulting in the improved properties. ignosulfonate derivative. Also, lignoSulfonates or residu The reaction of the lignosulfonate with the thionyl 3,438,959 3. 4. halide is carried out in a non-aqueous medium preferably react with at least 50% of the sulfonate radicals present in under substantially anhydrous conditions and in a ne the lignosulfonate, preferably from at least about 80% dium in which the particular lignoSulfonate is soluble. to the stoichiometric amount to react with the Sulfonate Thionyl chloride is generally used in the reaction due to radicals. Since the ignosulfonates as recovered may con its availability. Thionyl chloride is a good solvent for tain moisture and other constituents, even though purified, many lignosulfonates and thus may be used also as a re 5 which may utilize some of the thionyl halide, a 10% to action medium. 20% stoichiometric excess or more is often used. With a It is not necessary that the conditions be absolutely large excess of the thionyl halide, such as when the thionyl anhydrous, since any water present will react with the halide is used as the reaction medium, additional halogen thionyl halide to form a hydrogen halide and Sulfur di substitution in the lignin molecules may be obtained, espe oxide until the system becomes Substantially anhydrous. cially at the higher reaction temperature. At reaction Preferably, the reaction is carried out under reflux so temperatures above 50° C. and with excess thionyl halide that the acids or any other gaseous reaction products will present, an increase in the halogen content and a decrease be expelled from the system. A low boiling solvent or me in the hydroxy content in the product are generally ob dium is generally preferred to permit the reaction mix 5 tained indicating that some halogen substitution of the ture to be refluxed at temperatures below the decomposi hydroxy groups may have taken place. tion point of the thionyl halide without having to employ The following examples further illustrate the invention reduced pressures. and the properties of the intermediate product obtained. The lignosulfonate must be at least partially soluble in the solvent to effect the reaction with the thionyl halide. : EXAMPLE I Since there are relatively few non-aqueous solvents, Such A lignosulfonate intermediate or derivative was as, for example, dimethyl sulfoxide, which will dissolve prepared from a fermented calcium base spent sulfite metal salts of lignosulfonate, the lignosulfonate is general liquor. The liquor was fermented to convert the ferment ly converted to the acid form of an annine salt for which able sugars to alcohol and stripped to recover the alco more readily available solvents such as dioxane, tetrahy 2 5 hol. The alcohol-free liquor was then concentrated and drofuran, halogenated alkanes such as chloroform and adjusted to a pH of 0-3 and triamylamine added to halogenated aromatics as chlorinated benzene may be precipitate the lignosulfonate as a triamylamine salt. The used in addition to an excess of the thionyl halide. The salt thus obtained was washed with water and dried. term “lignosulfonate,' as used herein, means lignoSulfo Triamylamine lignosulfonate in an amount of 70 g. nate in its acid form as well as Salts thereof. 30 was added to a solution containing 150 g. of thionyl Since a common method of recovering lignosulfonates chloride and 150 ml. of chloroform, while stirring, and from a sulfonated lignin-containing material or pulping the resulting reaction mixture was refluxed for 3 hours. liquor is by precipitation or solvent extraction of the sul The solvent, the unreacted thionyl chloride and other fonated lignin as an amine salt, the amine salts of ligno volatiles were then flashed off under vacuum. A portion sulfonate are preferably used for the reaction with the of the resulting intermediate product was washed with thionyl halide. The formation of the amine salt is usually water 3 times and analyzed. The product was a brown obtained by the addition of an amine to a lignosulfonate powder. containing aqueous solution which, under acid conditions, The analysis and properties of the intermediate prod will result in the precipitation of the lignosulfonate amine uct as compared to lignosulfonic acid are shown below: salt. A primary, secondary or tertiary amine may be used. 40 The amine may be an alkyl amine having from 3 to 30 carbon atoms or an aryl amine of about the same num ber of carbon atoms. The alkyl radicals or substituents Lignosulfonic Intermediate can be either saturated or unsaturated as well as cyclic. acid product Percent Cl 0.0 11.0 Generally, it is preferred to have an amine of at least 8 Percent S- 5.4 6.3 carbon atoms so that the solubility of the amine lignosul Percent N- 0.0 ... 5 fonate salt in water is sufficiently low to precipitate more I.R.------() ------readily from the solution. Illustrative examples of the 1 New peaks at 7.4 and 8.4 p, and intensity of -OH peaks of lignosulfonic amines which may be used are triamylamine, fatty amines, acid is decreased by about one-half. dioctylamine and octylaniline. SOLUBLITIES While the thionyl halide will react with the sulfonated Acetone------Vy sparingly solu- Very soluble. lignin at room temperature, it is generally preferred to e. Chloroform---- - Insoluble Slightly soluble. heat the reaction medium to a temperature in the range Water------Soluble- Insoluble. of from 50° C. to 70° C. or up to the decomposition 10% aqueous NaO - - - - - do - Slowly goes into solu point of the thionyl halide. The rate of reaction of thionyl Solution. tion upon heating. halide with the Sulfonated lignin is rapid, increasing ap 5 preciably with an increase in temperature. At the pre ferred temperature of 50° C. to 70° C., generally a re action time of 2 to 4 hours is used. However, a reaction The nitrogen content in the intermediate product was time of from 5 or 10 minutes to 24 hours may be em believed to be in the form of triamylammonium sulfate ployed. After the reaction, the solvent or excess reactant 60 and triamylammonium chloride which were not com such as thionyl chloride, if used as a reaction medium, pletely removed from the product by washing. is evaporated with other volatiles which may have been EXAMPLE II formed. The intermediate product of the invention after A spray dried fermented calcium base spent sulfite the evaporation of the solvent is a dark brown powder. liquor in an amount of 300 g. was dispersed in 1500 ml. The product may be stored under anhydrous conditions of methanol and 100 g. of Cl2 were bubbled into the preferably at a low temperature. While the dry product resulting dispersion at 10 C. The methanol and the is relatively stable, it may undergo some condensation if HCl formed in the chlorination were evaporated off at stored for a considerable length of time. The intermediate Toom temperature. The chlorinated lignosulfonate constit product slowly dissolves in aqueous alkaline solutions and uents were recovered from the chlorinated spent sulfite is soluble in chloroform, acetone, ethanol and insoluble in liquor by the selective solubility of the triamylamine Water. lignosulfonate salt in butanol. The chlorinated spent sul The ratio of the thionyl halide intermixed with the fite liquor solids, free of methanol, were dispersed in a lignosulfonate may be widely varied. Generally, it is pre mixture of butanol and water and triamylamine was ferred to use Sufficient amount of the thionyl halide to added to the mixture until a pH of about 5 was obtained. 3,438,959 5 6 The butanol phase, containing most of the triamylamine the pH of the system was maintained at about 9 by addi salt of chlorinated lignosulfonate formed by the addition tion of amine. of the triamylamine, was washed with water three times The resulting N-dodecylchlorolignosulfonamide was re to remove the carbohydrates and other non-lignin consti covered from the reaction mixture by the evaporation of tuents. The alcohol was evaporated and the vacuum dried the chloroform and washing with acidic acetone-water product was washed two times with diethyl ether and mixture to remove the excess amine. The chloroligno once with petroleum ether to remove the excess amine Sulfonamide obtained was a semi-solid product which and residual butanol. Weighed 41 g. after vacuum drying. The dry triamylamine salt of chlorinated lignosulfonate To illustrate the surface active properties of the chlo in an amount of 90 g. was dissolved in 600 ml. of rolignoSulfonamide, it was tested as water-in-oil emulsi chloroform and 42 g. of thionyl chloride were added with IO fier. Ten grams of the chlorolignosulfonamide prepared stirring at room temperature. The resulting reaction mix above were mixed with 200 ml. of diesel oil and about ture was refuxed for 3 hours after which the solvent and 4 g. of a 25 weight percent sodium hydroxide solution. the volatiles were flashed off under the vacuum. The To the mixture, 150 ml. of saturated salt brine were added intermediate as a viscous residue was obtained which was and the mixture continually mixed for 30 minutes. The redissolved in 200 ml. of chloroform, stirred for 10 min Stability of the emulsion system was tested by the addi utes and the chloroform was flashed off. tion of more saturated brine under the continual mixing A portion of the product was further purified by dis until a phase conversion or coagulation of the water-in solving the product in a minimum amount of acetone and oil emulsion was obtained. Seventeen hundred milliliters pouring the solutions into water to precipitate the inter of the Saturated brine were added before the phase con mediate. The precipitation was washed three times with version or coagulation occurred. An emulsifier which will Water and dried at 40 C. to 45 C. under vacuum. The permit addition of more than 1000 ml. before the phase resulting intermediate product was a brown powder conversion is generally considered a good emulsifier. Weighing 21 g. and had the following analysis and prop What is claimed is: erties: 1. A composition comprising a lignosulfonate reacted under substantially anhydrous conditions with a thionyl Trianayamine halide Selected from the group consisting of thionyl chlo salt of Intermediate ride and thionyl bromide, said lignosulfonate being re chlorinated product lignoSulfonates acted with the thionyl halide at a temperature in the 30 range of from room temperature to the thermal de Percent N------6 1. Percent Cl, organic------2. composition temperature of the thionyl halide. Percent Cl, inorganic 2. A composition according to claim 1 wherein the Percent sulfonate S------thionylhalide is thionyl chloride. Percent nonsulfonate S 3. A composition according to claim 1 wherein the thionylhalide is thionyl bromide. New peaks at 7.4 and 8.4, which correspond with those of sulfonyl 4. A composition according to claim 1 wherein the chloride. lignoSulfonate and thionyl halide are reacted in a medium Selected from the group consisting of an excess of the SOLUBILITIES thionyl halide, chloroform, benzene, tetrahydrofuran, di Acetone------Soluble------Very soluble. 40 Chloroform. Swells or slightly soluble. Oxane and mixtures thereof. Ethanol Soluble. 5. A composition according to claim 4 wherein the Water.-- Insoluble. lignoSulfonate is a fraction of a spent sulfite liquor having an average molecular weight such that its diffusion coef. ficient is in the range of 14 to 20 mm.2/day. EXAMPLE III 6. A composition comprising a lignosulfonate reacted A fermented calcium base spent sulfite liquor was With a halogen having an atomic number in the range of chlorinated in a manner similar to that described in Ex 17 to 35 and subsequently reacted under substantially ample II except that 110 g. of chlorine were used per anhydrous conditions with a thionyl halide selected from 100 g. of spray dried solids and that after evaporation of the group consisting of thionyl chloride and thionyl bro the methanol and the hydrogen chloride formed as a mide, Said halogen-reacted lignosulfonate being reacted result of the chlorination, the chlorinated lignosulfonate 50 With the thionyl halide at a temperature in the range of was dissolved in a 5% sodium hydroxide solution and from room temperature to the thermal decomposition allowed to remain at 80 C. overnight. The pH of the temperature of the thionyl halide. solution during this time was kept above 12. 7. A composition according to claim 6 wherein the The chlorinated lignosulfonate constituents were 55 gen is chlorine and the thionyl halide is thionyl chlo recovered from the sodium hydroxide treated solution as the triamylamine salt by the addition of triamylamine 8. A process for the preparation of a halogenated with hydrochloric acid. The triamylamine salt formed lignosulfonate which comprises intermixing under sub was extracted from the solution with chloroform. The stantially anhydrous conditions lignosulfonate with a chloroform was evaporated and the residue was dissolved 60 thionyl halide selected from the group consisting of in a minimum amount of acetone and the resulting solu thionyl chloride and thionyl bromide, said lignosulfonate tion was slowly poured into water with agitation to pre being intermixed with the thionyl halide at a temperature cipitate the triamylamine salt of the chlorinated ligno in the range of from room temperature to the thermal Sulfonate. The product was washed with water and dried. decomposition temperature of the thionyl halide. To 40 g. of the triamylamine salt of the chlorinated 9. A process according to claim 8 wherein the ligno lignoSulfonate dissolved in 400 ml. of chloroform, 40 Sulfonate is a lignosulfonate fraction from a spent sulfite g. of thionyl chloride were added slowly. The reaction liquor, intermixed with thionyl chloride at a temperature mixture was refluxed for 3 hours after which the solvent in the range of 50° to 70° C. and the volatiles were flashed off under vacuum. The 10. A process for the preparation of a halogenated intermediate product obtained as the residue was used in O lignosulfonate, which comprises Sulfonating a lignin-con the preparation of N-dodecylchlorolignosulfonamide. taining material to thereby convert the lignin to a ligno The intermediate product was dissolved in chloroform Sulfonate, separating the lignosulfonate from the reaction and 60 g. of dodecylamine likewise dissolved in chloro mixture and intermixing under Substantially anhydrous form was slowly added with stirring. The resulting homo conditions the lignosulfonate with thionyl halide selected geneous mixture was stirred for 3 hours at 50° C. while 75 from the group consisting of thionyl chloride and thionyl 3,438,959 7 8 bromide, said lignosulfonate being intermixed with the halogenated lignosulfonates with a thionyl halide selected thionyl halide at a temperature in the range of from room from the group consisting of thionyl chloride and thionyl temperature to the thermal decomposition temperature bromide, said prehalogenated lignosulfonate being reacted of the thionyl halide. with the thionyl halide at a temperature in the range of 11. A process according to claim 10 wherein the thionyl from room temperature to the thermal decomposition of halide and lignosulfonate are intermixed in an inert non the thionyl halide. aqueous solvent wherein said lignosulfonate and said 17. A process according to claim 16 wherein the thionyl halide are at least partially soluble. halogen is chlorine and the thionyl halide is thionyl 12. A process according to claim 10 wherein the ligno chloride. sulfonate is separated from the sulfonated lignin-con 18. A process according to claim 17 wherein the sul taining material by intermixing the sulfonated lignin O fonated residual pulping liquor is a spent sulfite liquor containing material with an organic amine, having from and the lignosulfonates are separated by precipitation of 3 to 30 carbon atoms selected from the group consisting the lignosulfonates as an alkyl amine salt. of primary, secondary, and tertiary amines to thereby 19. A process according to claim 17 wherein the pre recover the sulfonated lignin as an amine salt. 5 halogenated lignosulfonate and thionyl chloride are in 13. A process according to claim 10 wherein the ligno termixed in a non-aqueous inert solvent wherein the pre sulfonate and thionyl halide are intermixed in a solvent halogenated lignosulfonate and the thionyl halide are at selected from the group consisting of chloroform, benzene, least partially soluble. dioxane, tetrahydrofuran, and an excess of the thionyl 20. A process according to claim 17 wherein the pre halide. halogenated lignosulfonate and thionyl chloride are inter 14. A process according to claim 13 wherein the sul mixed in a non-aqueous solvent selected from the group fonated lignin-containing material is a spent sulfite liquor. consisting of chloroform, dioxane, tetrahydrofuran, ben 15. A process according to claim 13 wherein the zene, and an excess of thionyl chloride. thionyl halide is thionyl chloride. 16. A process for the preparation of a halogenated References Cited lignosulfonate from a sulfonated residual pulping liquor, Brauns: “The Chem. Lignin,” 1952, p. 324. which comprises separating the lignosulfonates from the Brauns et al.: "Chem. of Lignin,” sup. vol. pp. 291 residual pulping liquor, contacting the lignosulfonates and 297. with a halogen having an atomic number in the range of 17 to 35 to prehalogenate the lignosulfonates, and re 30 CHARLES B. PARKER, Primary Examiner. acting under substantially anhydrous conditions the pre D. R. PHILLIPS, Assistant Examiner.