Group 13 sulfides hydrogen halides

Aqueous solutions of hydrogen sulfide, selenide, and telluride are acidic acid strength increases as the group is descended H2S < H2Se < H2Te. The same trend was observed for increasing acidity of the hydrogen halides. The acid ionization constants are... 

The halogen functional polymer can react with a thiol by nucleophilic reaction, resulting in a polymeric thioether and a hydrogen halide. The latter is trapped by a basic additive, preventing a reverse reaction. Snijder et al. [135] used this technique to modify the end group of poly( -butyl acrylate) into a hydroxy-functional polymer. With 2-mercaptoethanol, the yield of functionalization was higher with the addition of 1,4-diazabicyclo[2,2,2]octane (DABCO) to the reaction mixture. The addition of DABCO allows for the formation of a sulfide anion, which is a stronger nucleophile. They studied this... 

Ion exchange, in which cation and/or anion resins are used to replace undesirable anionic species in liquid solutions with nonhazardous ions. For example, cation-exchange resins may contain nonhazardous, mobile, positive ions (e g., sodium, hydrogen) which are attached to immobile acid groups (e.g., sulfonic or carboxylic). Similarly, anion-exchange resins may include nonhazardous, mobile, negative ions (e.g., hydroxyl or chloride) attached to immobile basic ions (e.g., amine). These resins can be used to eliminate various species from wastewater, such as dissolved metals, sulfides, cyanides, amines, phenols, and halides. 

Very little is known about chalcogenide halides of Group IVB elements. Although the existence of sulfide chlorides (45, 274, 329, 365) and of a selenide chloride (329) of titanium was claimed in early publications, their true composition, and even their existence, remains doubtful. They have usually been obtained by the reaction of titanium chlorides with sulfur and selenium, respectively, or with hydrogen sulfide. The synthesis of a pure compound, TiSClj, was published in 1959 (113). It is an intermediate of the reaction of TiCU with HjS. 

Just as in the case of aromatic compounds isoparaffins can be alkylated with sources of alkyl groups other than olefins. Alkyl halides, alcohols, ethers, mercaptans, sulfides, etc., can be used. When olefins are used some alkyl fluorides from a combination of olefin and hydrogen fluoride are always formed. The quantity of this in the product can be greatly reduced by providing conditions under which the alkyl fluoride is used in alkylation. The apparent paradox is provided, in that the fluoride content of the product is lessened by further treatment with hydrogen fluoride. A more thorough treatment of the details of the alkylation of isoparaffins with olefins is found elsewhere in this volume. 

A number of anhydro sugars are known that contain nitrogen, sulfur, or selenium. Tri-O-acetyl thioglucosan was first prepared in 1963 by Akagi and co-workers by treatment of S-gluco-syl dithiocarbonate (21 O Fig. 2) with sodium methoxide [74]. Since that time, numerous syntheses have been reported that rely on the introduction of a thioester at C-1 or C-6 and the activation of the alternate position with a halide or sulfonate group [75,76]. Treatment of a doubly activated hexopyranose such as (24) with hydrogen sulfide and triethylamine... 

Several thiols occur naturally for example, skunk secretion contains 3-methyll-butanethiol and cut onions evolve 1-propanethiol, and the thiol group of the natural amino acid cysteine plays a vital role in the biochemistry of proteins and enzymes (see Introduction, p. 2). Primary and secondary thiols may be prepared from alkyl halides (RX) by reaction with excess sodium thiolate (SN2 nucleophilic substitution by HST) or via the Grignard reagent and reaction with sulfur. Tertiary thiols can be obtained in good yields by addition of hydrogen sulfide to a suitable alkene. Thiols can also be prepared by reduction of sulfonyl chlorides (Scheme l).la,2a... 

For such reactions to succeed with aryl halides the halogen must be particularly reactive. For example, o-halobenzoic acids give o-mercaptobenzoic acid when heated with an alkali hydrogen sulfide in the presence of copper powder under pressure 265 and / -chloronitrobenzene gives / -aminothiophenol when heated with an excess of sodium sulfide in aqueous solution, the nitro group being simultaneously reduced.266... 

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