by Anuja A. Sawant of Prof. G. S. Shankarling

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1 Seminar on Greener methods for batch sulfonation Presented by Anuja A. Sawant Under the guidance of Prof. G. S. Shankarling

2 Introduction Sulfonation is introduction of SO2X SO2OH These groups attach to C N

3 Classification of sulfonates C Aliphatic & Alicyclic C Aromatic C Heterocyclic N N-sulfonates Or Sulfamates

4 Types of Sulfonates Dyes Paraffin sulfonates Dye Intermediates Fatty acid ester sulfonates Naphthalene sulfonates Petroleum Sulfonates Alkylated Aromatics Lignosulfonates Aliphatic Sulfonates or Hydroxysulfonates Sulfosuccinates and Sulfosuccinamates Monomer and Polymer Sulfonates

5 Applications of Sulfonates

6 Sulfonating agents Sulfonating Agents Sub-types Sulfur trioxide and compounds Sulfur trioxide, oleum, concentrated sulfuric thereof acid (SO3 plus water) Chlorosulfonic acid (SO3 plus HCl) Sulfur trioxide adducts with organic compounds Sulfamic acid The sulfur dioxide group Sulfurous acid, metallic sulfites Sulfur dioxide with chlorine Sulfur dioxide with oxygen Sulfoalkylating agents Sulfomethylating agents (hydroxyl- and aminomethanesulfonates) Sulfoetylating agents (hydroxyl-, chloro-, and methylaminoethanesulfonates; ethylenesulfonic acid) Miscellaneous sulfoalkylating agents; sulfoacylation; sulfoarylation; sulfatoalkylation

7 Advantages of Batch Processes 1 Small scale production 2 Range of different products to be produced in the same equipment 3 Reactions requiring long reaction times 4 Reactions with superior selectivity

8 Design Features for Sulfonation Agitation Heat Transfer Sulfonation reaction mixtures are Viscous inefficient heat exchange poor product quality and/or reduced productivity

9 Non-green aspects of Sulfonation methods Dilute sulfuric acid Neutralization of acid Inherent properties of sulfonating agents Large inventories of sulfonating agents Swelling agents Formation of toxic reactional residues Undesirable Salt waste streams High temperature conditions Recyling of sulfonating agents By-products like sulfone

10 Aims of Green Batch Sulfonation Reactions that can be carried out at room temperature and Improved yields. Improved conversions. Improved selectivity. Reduction or elimination of by- consume less energy. Reactions that use raw materials those are easily available. products such as sulfones. Lowers waste stream issues. Simplicity of the process. Shorter reaction time. Enhancement in reaction rates. Use of stoichiometric quantities of sulphonating agents. Reactions that can be carried out at in solvent-free conditions.

11 Literature Survey Sulfonating agents Sulfonation with silica sulfuric acid Conditions Microwave Assisted Sulfonation Chemical Recycling of Polystyrene. Sulfonation Ultrasound with Different assisted Sulfonation Agents regioselective sulfonation Sulfonation using SO3DMF complex Process Catalyst Sulphonated Polymer Sulfonation Resin of an aromatic Sulfonation process compound forming crystalline product Sulfonation process forming free-acid form of the product

12 Sulfonating agents

13 A novel method for sulfonation of aromatic rings with silica sulfuric acid With solvent (1,2-dichloroethane) Without solvent/excess substrate Lower yield Higher yield

14 A novel method for sulfonation of aromatic rings with silica sulfuric acid Conventional methods for Newer greener method sulfonation of aromatic compounds Sulfonic acids are often in equilibrium with sulfones as a byproduct Sulfones are not produced at all Sulphuric acid causes destruction of Silica sulphuric acid does not cause acid sensitive functional groups destruction of acid sensitive functional groups

15 Procedure ArH + SIO2O-SO3H --> ArSO3H +SIO2-OH RBF charged with silica sulfuric acid + aromatic compound Magnetic stirrer Conditions: 80 C for 30min Mixture then was filtered, washed with dichloromethane, and the solvent was removed under reduced pressure. The residue was washed with n-hexane and dried in air to produce white solid (75% yield)

16 Chemical Recycling of Polystyrene. Sulfonation with Different Sulfonation Agents Newer greener method using silica sulfuric acid as compared to the conventional method using sulfuric acid Reaction Simplified Separation of products from acid and solvent Easier

17 Method for the sulfonation of compounds comprising free hydroxyl (OH) groups or primary or secondary amines Conventional methods Newer greener method Formation of potentially toxic reactional residues Avoids introduction of toxic substances that are difficult or impossible to eliminate completely. SO3-pyridine Uses SO3:DMF complex Pyridine's toxicity to humans is well known Performed at a very acid ph value Avoids the use of excessively acidic ph values by using an acid capture agent(2-methyl-2-butene). Structural integrity of the initial polymer is not altered.

18 Procedure Solubilization or preparation of a homogeneous solution of the compound to be sulfonated in an anhydrous solvent or cosolvent such as dimethylformamide (DMF) Addition at ambient temperature (about C) of a molar excess of an acid capture agent such as 2-methyl-2-butene, miscible in the cosolvent. Rapid addition of the SO3-DMF complex under agitation. Stopping the reaction by progressive addition of the mixture to an alkaline solution, e.g., a 2% solution of sodium bicarbonate (NaHCO3) or another alkali Purification of the sulfonated compound obtained by tangential ultrafiltration against water

19 Conditions

20 Microwave Assisted Sulfonation of 2-Naphthol by Sulfuric Acid: Cleaner Production of Schaeffer s Acid Without microwave With microwave At least 200 times excess sulfuric acid is Effect of MW irradiation on Performance of employed for monosulfonation 2-Naphthol sulfonation Molar Ratio 2-N conversion % S:2-N = 1.5:1 did not achieve S:2-N = 1:1 specified conversion S:2-N = 2:1 73 O:2-N = 2:1 S:2-N =2.5:1 Molar Ratio 2-N conversion % Requires more time Requires lesser time Activation energy required is more Activation energy required is lesser

21 Procedure Frequency: 2450 Mhz For each run, sulfuric acid (S) or oleum (O) and 2-naphthol (2-N) were mixed to prepare a homogeneous slurry by maintaining C Reactions were carried out at different temperatures and powers.

22 Advantages Efficient and rapid transformation of energy and heating throughout the volume Reduction in reaction time Utilizes only a stoichiometric quantity of sulfuric acid leading to minimum effluent generation Increase in conversion Enhanced selectivity

23 Ultrasound assisted regioselective sulfonation of aromatic compounds with sulfuric acid Substrate Condition Time Conversion Selectivity (%) (%) Product Toluene Silent 24h Toluene-4sulfonic acid Toluene ))))) 45min Toluene-4sulfonic acid

24 Procedure RBF was placed at the center of Ultrasonic Bath Sulfonating agent: sulfuric acid Toluene was added Sulfuric acid (98 wt%) was added Reaction mixture sonicated at 25 C Frequency: 33 khz Power: 100 W HPLC analysis of samples

25 Advantages Solvent free conditions Ultrasound is the promoter Enhancement in reaction rate Improved selectivity Improved conversion

26 Process

27 Sulphonated Polymer Resin and Preparation Thereof Conventional methods for preparing Newer greener method a sulphonated polymer resin Uses swelling agent, such as chlorohydrocarbon Avoids the use of a swelling agent Products obtained are not physically Products obtained are stable stable but they tend to break Conventional resins sulphonated with sulphuric acid have lesser activity Macroporous resins prepared have been found to have better activity

28 Procedure Reaction Conditions: 50 and 100 Pa 40 to 80 C The polymer resin: typically sulphonated in a particle form Sulfonating agent: pure gaseous sulphur trioxide After-treatment to prevent breakage of the resin structure

29 Sulfonation of Polyhydroxyaromatics Conventional methods Process with catechol Process with pyrogallol Process with Protocatechuic acid (PCA) Uses oleum or fuming sulfuric acid Lead to product mixtures, or make an alkali metal salt product Complicates recycling of the sulfonylation agent Often requires high temperature for a significant time Newer greener method Avoids the use of oleum or fuming sulfuric acid Neutralization required Lower waste production Runs at RT or elevated temperature Neutralization required PCA is obtained from microbial synthesis The product precipitates from the reaction solution as the free acid. No neutralization

30 Sulfonation of Polyhydroxyaromatics Formula I: R = SO3H or CO2H, R2 = H or OH When R = SO3H or CO2H, R2 = H, product is Tiron TM When R = SO3H or CO2H, R2 = OH, product is 4,5,6-trihydroxy-1,3benzenesulfonic acid When R = CO2H, R2 = H, product is 3,4dihydroxy-5-sulfobenzoic acid Formula II: R = H OR CO2H R2 = H OR OH When R & R2 = H, compound is catechol. When R is H, R2 is OH, compound is pyrogallol. When R is CO2H, R2 is H, compound is protocatechuic acid.

31 Procedure RBF: conc. sulfuric acid + catechol at RT Mixture was heated to 95 C for 5h Mixture was cooled to 50 C, NaOH was added Precipitate 1,2-dihydroxy-3,5benzenedisulfonate sodium salt. Mixture was cooled to C Precipitate was filtered The solid was washed with isopropanol (600 ml) and dried under vacuum at 60 C to yield 312g (73% yield) of 1,2dihydroxy-3,5benzenedisulfonate sodium salt as an off-white solid. Sulfonation of Catechol in Concentrated H 2SO4

32 Sulfonation method for zonisamide intermediate in zonisamide synthesis and their novel crystal forms Conventional methods Newer greener method Formation of by-product Does not use dioxane and eliminates the problem of the waste. Reagent chlorosulfonic acid is used in large excess Chlorosulfonic acid:dioxane complex is used which is not safe

33 Procedure Reactor: ethyl acetate + H2SO4, 98% + acetic anhydride Mixture was cooled to -5 C BOA (benzisoxazole acetic acid )was added Reflux: 4h Cooled to RT and NaOH was added Product: precipitates as sodium salt (Crystalline forms of benzisoxazole methane sulfonic acid (BOS-H) and its salts (BOS-Na, NOS-Ca, and BOS-Ba)) After 2h precipitate was filtered, washed and dried The yield was grams BOA-Na having 100% purity by HPLC

34 Catalyst

35 Process for sulfonation of an aromatic compound Conventional method for sulfonation Newer greener method of aromatic compounds Uses aluminum chloride which is Corrosive Used in large amounts Separation of AlCl3 is lengthy and expensive Cannot be recycled Uses catalytically effective amount of a mixture of bismuth tri-halide and of perfluoroalkanesulfonic acid

36 Procedure Sulfonation of the aromatic compound Hydrolysis Reaction mixture: 20 C and 200 C, atmospheric pressure Catalytic mixture, some part of which is in the salt form is filtered, dried and recycled Desired product: is recovered from organic phase sulfonated aromatic product is subsequently recovered from the organic phase according to known techniques, by removing the organic solvent, by distillation or by crystallization

37 References Karki A., Paatero E., Heikkila H., Mononen H., Paananen H., Tiihonen H. Sulphonated polymer resin and preparation thereof. US 6,664,340 B1. (16 Dec., 2003) Hajipour A. R., Mirjalili Bi. Bi. F., Zarei A.,Khazdooz L. and Ruoho A. E. "A novel method for sulfonation of aromatic rings with silica sulfuric acid",tetrahedron Letters, 45, , (2004) Sułkowski W. W., Nowak K., Sułkowska A., Wolińska A., Bajdur W. M., Pentak D. and Mikuła B. Chemical recycling of Polystyrene. Sulfonation with different sulfonation agents, Mol. Cryst. Liq. Cryst., 523, 218=[790] 227=[799], (2010) Dubac J., Le Roux C., Repichet S. Process for the sulfonation of an aromatic compound. US 6,455,738. (24 Sep., 2002) Umrigar V. M., Chakraborty M. and Parikh P. A. Microwave Assisted Sulfonation of 2-Naphthol by Sulfuric Acid: Cleaner Production of Schaeffer s Acid, Ind. Eng. Chem. Res., 46, ,(2007) Qureshi Z. S., Deshmukh K. M., Jagtap S. R., Nandurkar N. S., Bhanage B. M. Ultrasound assisted regioselective sulfonation of aromatic compounds with sulfuric acid, Ultrasonics Sonochemistry,16, ,(2009) U.S. Patent Application No. 12/859,922, Publication No. 2011/ A1 (published Feb. 24, 2011) (Frost J., Bui V., applicant) Petit E., Garcia-Papy D., Barbier-Chassefiere V. Method for the sulfonation of compounds comprising free hydroxyl (OH) groups or primary or secondary amines. US 7,396,923 B2. (8 Jul., 2008) Mendelovici M., Nidam T., Schwartz E., Wizel S. Sulfonation method for zonisamide intermediate in zonisamide synthesis and their novel crystal forms. US 6,841,683 B2. (11 Jan., 2005)

Sulfonation Chemistry more sustainable approaches RSC Symposium, Basel, June 1-2, Dr. Jörg Schrickel Marketing Manager Intermediates CABB AG

Sulfonation Chemistry more sustainable approaches RSC Symposium, Basel, June 1-2, 2016 Dr. Jörg Schrickel Marketing Manager Intermediates CABB AG Content Conventional sulfonation reactions Where they are