Liquid Sulfur Dioxide as Solvent Medium for Chemical Reactions

Abstract

OtTuOOi forms. This compound was reported by Ollard (14) and has since been observed by Kasper (8) and the author. In view of the ease with which complex chromichromates form, even in highly acid solution, it is concluded that in chromic dichromate (and, to a lesser extent, in aluminum dichromate) solutions, there exists a progressive hydrolysis in which the two chromate complexes described above form from the dichromate complex. In complete accord with this hypothesis is the low pH at equilibrium of chromic dichromate solutions, as compared to the other compounds studied. No change in pH with time was observed with the perchlorate solutions, confirming the original assumption that they would be free from complex formation.Since anodic oxidation is a result of the potential of oxygen discharge at the anode, which in turn is a function of hydrogen-ion activity, pH would be expected to be an important variable in the control of anodic baths. This has been shown to be the case (1, 17). However, since baths high in chromic acid and aluminum content have been shown to possess proportionately greater hydrogen-ion activity, consideration must be given to this fact in determining the most economical operation of the anodic bath. The laboratory work of Tarr, Darrin, and Tubbs (17) has considered this point thoroughly, and the work has been confirmed by service records of anodic baths in commercial operations (18).

Sulfonation

“…Liquid sulfur dioxide has been employed as a solvent for the sulfonation of benzene (256). These authors concluded that the economically most attractive processes involve sulfonation of benzene with gaseous sulfur trioxide, or benzene vapors with sulfuric acid, in a continuous manner.…”

Metal-free glycosylation with glycosyl fluorides in liquid SO2

“…The latter approach is used on industrial scale, where processes dealing with a recirculation of SO 2 in a closed contour are well known. Since the first report by Walden at the beginning of the 20th century [40], a variety of Lewis acid-mediated chemical transformations [41][42][43][44][45], especially those with carbenium ion intermediates [46][47][48][49][50][51][52][53][54][55][56], have benefited from the use of liquid SO 2 as the reaction medium. To the best of our knowledge, there has been only one example where liquid SO 2 has been applied as the glycosylation medium to stabilize the oxocarbenium ion formed from glycosyl perchlorate that is generated in situ from glycosyl chloride and AgClO 4 [56].…”

Chalcogen Bonding of SO2 and s‐Block Metal Iodides Near Room Temperature: A Remarkable Structural Diversity

“…tion into multiple bonds. [7,8] Consequently, SO 2 was also described as a useful molecule to establish C-C bonds, [9] which is generally one of the key targets in organic chemistry.…”

“…As these salts are predominant in general inorganic chemistry, also applications within organic chemistry were established. Sulfur dioxide can be used in a large variety of reactions which allow functionalization due to SO 2 insertion into multiple bonds , . Consequently, SO 2 was also described as a useful molecule to establish C–C bonds, which is generally one of the key targets in organic chemistry.…”