Solvents sulfolane

The Sulfinol gas conditioning process of Shell uses dksopropanolamine in a sulfolane solvent system. This system also increases gas capacity with improved efficiencies (152). 

A number of carboxylic acids other than acetic were investigated as solvents or promoters. All of these acids which were stable to reaction conditions were found to be effective in promoting glycol ester production (e.g., propionic, pivalic, benzoic, etc.). However, other Br nsted acids of non-carboxylic nature were not found to be effective promoters. Thus penta-chlorophenol, although it has a pKa value (4.82) very close to that of acetic acid (4.76), is not a comparable promoter (Table I, reaction 13). Likewise, phosphoric acid (pK 2.15) is not an effective solvent or co-solvent with acetic acid (Table I, reaction 8). Experiments with lower concentrations of these acids in sulfolane solvent also showed that carboxylic acids are unique in promoting glycol formation. The promoter function of carboxylic acids thus appears not to be dependent (only) upon their acidity, but on some other chemical or structural property. 

An increased selectivity for phenol in the oxidation of benzene by H202 with TS-1 catalyst in sulfolane solvent was attributed to the formation of a bulky sulfolane-phenol adduct which cannot enter the pores of TS-1. Further oxidation of phenol to give quinones, tar, etc. is thus avoided. Removal of Ti ions from the surface regions of TS-1 crystals by treatment with NH4HF2 and H202 was also found to improve the activity and selectivity (227). The beneficial effects of removal of surface Al ions on the catalytic performance of zeolite catalysts for acid-catalyzed reactions have been known for a long time. 

In the industrial process [12] 1,3-butadiene and water are reacted at 60-80 °C in an aqueous sulfolane solvent in the presence of triethylamine hydrogencarbonate under 10-20 bar CO2 pressure. The reaction yields linear telomers mainly, with a 90-93 % selectivity to 2,7-octadien-l-ol together with 4-5 % l,7-octadien-3-ol. Most of the products are removed from the reaction mixture by extraction with hexane, and the aqueous sulfolane phase with the rest of the products, the catalyst and the ammonium bicarbonate is... 

Fig. 19. Effect of catalyst concentration on rates to methanol and ethylene glycol by an iodide-promoted ruthenium catalyst (191). Reaction conditions 75 ml of N-methylpyrrolidone ( ) or sulfolane ( ) solvent, [KI] = 6[Ru], 850 atm, 230"C, H2/CO = 1.

Studies of I /Ru stoichiometry previously discussed and shown in Fig. 20 suggest that these two complexes, or at least a catalyst composition of the same stoichiometry, are present during catalysis. Studies of active solutions during catalysis by high-pressure infrared spectroscopy have also confirmed the presence of these complexes (191). Under 544 atm of H2/CO at 230°C in sulfolane solvent, the infrared absorptions for the carbonyl ligands of both complexes are observed clearly. No other carbonyl absorptions are evident. Samples have also been withdrawn from catalytic reactions and cooled immediately to low temperature before analysis by infrared spectroscopy these solutions also are found to contain only [HRu3(CO)j J and [Ru(CO)3I3]. ... 

This means a reaction order with respect to PA between zero and 1. The value of 0.5 which is found indicates a relatively strong adsorption of PA (K3Cpa non-negligible with respect to 1). On the other hand, the very polar sulfolane solvent is more strongly adsorbed than the PA reactant (KdCs 1 + KaCpA) and thus ... 

Zeolite polarity and reaction rate The competition between sulfolane, PA and product molecules for the adsorption on the active protonic sites is sufficient enough to explain the differences in reaction orders and catalyst stability and selectivity between PA transformation in sulfolane and in dodecane. However, the competition for the occupancy of the zeolite micropores plays a significant role as well. This was demonstrated by studying a related reaction the transformation of an equimolar mixture of PA with phenol in sulfolane solvent on a series of H-BEA samples with different framework Si/Al ratios (from 15 to 90).[49] According to the largely accepted next nearest neighbour model,[50,51] the protonic sites of these zeolites should not differ by their acid strength, as furthermore confirmed by the... 

Figure 3.8 Liquid phase transformation of phenyl acetate (2.2 mol l-1 in sulfolane solvent) at 433 K. (a) Yield in o-hydroxyacetophenone, o-HAP ( ) and p-hydroxyacetophenone, p-HAP (X) versus reaction time, (b) Effect of the addition of phenol (P) on the p-HAP yield. [P] =0 mol l-1 (x) and [P] =0.6 mol l-1 ( ). Reprinted from Catalysis Letters, Vol. 41, Jayat et al., Solvent effects in liquid phase Fries rearrangement of phenyl acetate using a HBEA zeolite, pp. 181-187, copyright (1996), Kluwer Academic Publishers, with kind permission of Springer Science and Business Media...

A kinetic study of PA transformation was carried out in a batch reactor over a HBEA zeolite[82] in the presence of nonpolar (dodecane) and very polar (sulfolane) solvents. The solvent polarity has a negative effect on the initial reaction rate, but a positive effect on the catalyst stability and selectivity for p-HAP (Table 3.7). 

UOP/Shell BTX, purification Reformate, pyrolysis gasoline Shell Sulfolane process liquid extraction and/or extractive distillation with sulfolane solvent 123 1998... 

IFP/Lyondell BTX, separation Pyrolysis, reformate, light oils Highly efficient sulfolane solvent separtaes BTX from feedstocks 19 1996... 

Recently, the use of sulfolane solvent allowed better kinetic control of the oxidation chain, with an increase of the selectivity to 80% or greater, at ca 8% benzene conversion. The by-products were catechol (7%), hydroquinone (4%), 1,4-benzo-quinone (1%) and tar (5%) [53, 54]. According to these authors, a rather stable complex, formed by hydrogen bonding with sulfolane, promoted desorption and hindered the re-adsorption of phenol, protecting it from consecutive oxidation (Equation 18.7). Actually, the rate of oxidation of phenol in the presence of sulfolane was only 1.6 times that of benzene, while it was 10 times higher in the presence of acetone. 

This equation can also explain the effect of Cp and Cpa on the rate of o-HAP formation in the sulfolane solvent if we admit that sulfolane is strongly adsorbed on the acid sites. Indeed, in this case, Ks Cs will be greater than the other terms of the denominator, which leads to reaction orders with respect to PA equal to 1 and to P equal to 0 i.e practically to the experimental values (Table 1). Therefore, if a solvation effect on the rate of o-HAP formation cannot be excluded, all the kinetic results can be explained just by the competition between sulfolane and the reactants for adsorption on the acid sites. 

We subsequently developed an efficient catalyst for oxidizing terminal olefins to ketones starting with a non-nitro based catalyst. This catalyst comprised PdCl2, CuCl, LiCl, CH3CN and CuCl2 in tetrahydrofuran or sulfolane solvent. No evidence of catalyst deactivation was observed even after >1(X) turnovers. 

Tetramethylurea Triethyl phosphate solvent, aprotic extraction Ethylene carbonate solvent, aprotic process N-Methyl-2-pyrrolidone solvent, aprotic process chemical synthesis Hempa Sulfolane solvent, aq. coatings... 

Polysorbate 60 Sulfolane solvent, polymerization media acrylic resin C8 alkyl acetate C9 alkyl acetate CIO alkyl acetate Cl3 alkyl acetate Oxo-heptyl acetate Oxo-hexyl acetate solvent, polymerizations Tetrahydrofuran solvent, polymers... 

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