Sulfur trioxide polymeric

Properties. Sulfur trioxide polymerizes easily in a variety of ways at room temperature. The simplest polymer is the trimer (I), or y form, which has the properties listed in Table 7-1 and is the only form of sulfur trioxide marketed as an article of commerce. 

Sulfur Trioxide. Pure sulfur trioxide [7446-11-9] at room temperature and atmospheric pressure is a colorless Hquid that fumes in air. This material can exist in both monomeric and polymeric forms. In the gaseous and Hquid state pure SO is an equiHbrium mixture of monomeric SO and... 

Figure 15.27 Structure of the monomeric, trimeric and chain-polymeric forms of sulfur trioxide.

P-parinaric acid, physical properties, 5 33t P-pentenoic acid, physical properties, 5 3 It P-peroxylactones, 18 484 Beta phase titanium, 24 838 in alloys, 24 854-856 properties of, 24 840, 941 P-phellandrene, 24 493 P-picoline, 21 110 from acrolein, 1 276 uses for, 21 120 P-pinene, 3 230 24 496-497 major products from, 24 478 /-menthol from, 24 522 as natural precursor for aroma chemicals, 3 232 terpenoids from, 24 478-479 P-propiolactone, polymerization of, 14 259 P-quartz solid solution, 12 637—638 Beta ratio, in filtration, 11 329—330 Beta (P) rays, 21 285 P-scission reactions, 14 280-281 P-skytanthine, 2 101 P-spodumene solid solution, 12 638-639 P-sulfur trioxide, 23 756 P-sultones, 23 527 P-tocopherol, 25 793 P-tocotrienol, 25 793 P-vinylacrylic acid, physical properties, 5 33t... 

The unsulfonated random copolymers are reportedly synthesized at 50 °C over a period of 48 h using emulsion polymerization with dodecylamine hydrochloride surfactant in water as the reaction system and potassium persulfate as the initiator. The copolymer is then dissolved in an appropriate solvent such as dichloroethane or chloroform and sulfonated using reagents such as chlorosulfonic acid or a sulfur trioxide complex. It has been reported that this generation of BAM membranes exhibited some su-... 

The EPD properties of coordinated oxygen are also exemplified by the polymerization of sulfur trioxide ... 

Sulfur trioxide tends to polymerize, particularly in the presence of traces of water or sulfuric acid. The rate of its polymerization, however, decreases... 

The material is produced from naphthalene by oleum or sulfur trioxide sulfonation under conditions conducive to the formation of the h sulfonate. Subsequent reaction with formaldehyde leads to polymerization and the sulfonic acid is neutralized with sodium hydroxide [17] or lime. The process is illustrated in Fig. 2.2. The value of n is typically low but conditions are chosen to get a proportion of higher-molecular-weight product as it is believed to be more effective [18]. The quantity of sodium sulfate by-product formed by the neutralization of excess sulfonating reagent will vary depending on the process used, but can be reduced by a subsequent precipitation process using lime [19]. 

Solid sulfur trioxide exists in two well-defined modifications. Orthorhombic y-SOs consists of cyclic trimers (Figure 12.38a)/ which are converted by traces of water to the one-dimensional polymeric structure of monoclinic jl-SOi, (Figure 12.38b). In contrast, selenium trioxide forms a cyclic tetramer (Figure 12.38c). ... 

Long-chain alcohols, such as are obtained by the hydrogenation of coconut oil, polymerization of ethylene, or the oxo process (qv), are sulfated on a large scale with sulfur trioxide or chlorosulfuric acid to acid sulfates the alkali salts are commercially important as surface-active agents (see Surfactants). Poly(vinyl alcohol) can be sulfated in pyridine with chlorosulfuric acid to the hydrogen sulfate (84). 

In the reaction of ethylene with sulfuric acid, several side reactions can lead to yield losses. These involve oxidation, hydrolysis—dehydration, and polymerization, especially at sulfuric acid concentrations >98 wt % the sulfur trioxide can oxidize by cyclic addition processes (99). 

The range of preparatively useful electrophilic substitution reactions is often limited by the acid sensitivity of the substrates. Whereas thiophene can be successfully sulfonated in 95% sulfuric acid at room temperature, such strongly acidic conditions cannot be used for the sulfonation of furan or pyrrole. Attempts to nitrate thiophene, furan or pyrrole under conditions used to nitrate benzene and its derivatives invariably result in failure. In the case of sulfonation and nitration milder reagents can be employed, i.e. the pyridine-sulfur trioxide complex and acetyl nitrate, respectively. Attempts to carry out the Friedel-Crafts alkylation of furan are often unsuccessful because the catalysts required cause polymerization. 

Furan is resinified by sulfuric acid but it can be sulfonated with the complex of sulfur trioxide with pyridine or dioxane. Depending on conditions the 2-sulfonic or the 2,5-disulfonic acid may be obtained. Furan-2-carboxylic acid can be sulfonated with oleum. Benzo[6]furan is polymerized by sulfuric acid. The 2-sulfonic acid has been obtained by oxidation of the sulfinic acid available in turn by treatment of the lithio derivative with sulfur dioxide. Benzo[6]furan with the sulfur trioxide-pyridine complex allegedly affords the 3-sulfonic acid. 

Sulfur trioxide, SO3 (with boiling point 44.5° C) is monomeric in the vapor state, but several modifications of solid SO are recognized. There are at least two distinct polymeric forms, and a third solid form which has been found to contain six-membered rings ... 

Sulfur trioxide (SO3) is an industrially important compound key to the production of sulfuric acid. It tends to polymeric forms both in the solid and liquid states. As a gas, the molecules have a planar triangular structure in which the sulfur atom has a high affinity for electrons. This explains its action as a strong Lewis acid towards bases that it does not oxidize. It can thus crystallize complexes with pyridine or trimethy-lamine. It has a very strong affinity for water and hence rapidly associates with water in the environment. 

Trichloromethyl-l,2-oxathietane 2,2-dioxide is a catalyst for the acylation of alcohols and amines under mild conditions.It also catalyzes the polymerization of (NPCl2)3. It is suggested that six-membered cyclic sultones are derived from /3-sultones transiently formed in the addition of sulfur trioxide to alkenes. Ring-expansion of 3,4,4-trifluoro-3-trifluorovinyl-l, 2-oxathietane 1-oxide occurs at 100°C to give 4,4,5,6,7,7-hexafluoro-l,3-dioxa-2-thiacyclohept-5-Halogenation of 3,3,4,4-tetrafluoro-l,2-oxathietane 2,2-dioxide in... 

Sulfur trioxide, SOj. Mol. wt 80.07, m.p. 17°, b.p. about 45°. This reagent is available from the General Chemical Division, Allied Chemical and Dye Corp., under the name Sulfan B, a -y-form stabilized with an inhibitor to prevent polymerization. It is used in organic work chiefly in the form of complexes with dioxane, dimethylformamide, and pyridine. 

VM Fig. 15.16 The structures of solid state pol5unorphs of sulfur trioxide contains tetrahedral SO4 units (a) Y-SO3 consists of trimeric units and (b) a- and P-SO3 contain polymeric chains. Colour code S, yellow O, red. 

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