By addition of hydrogen

Cadmiumdl) sulphide, CdS, is a canary-yellow solid, precipitated by addition of hydrogen sulphide (or sulphide ion) to an acid solution... 

The selenoureas needed for condensation can usually be prepared by addition of hydrogen selenide to a solution of the corresponding cyanamides or carbodiimides. They can be less dangerously and quite... 

Vinyl Fluoride. Vinyl fluoride [75-02-5] C2H2F, the monomer for poly(vinyl fluoride), is manufactured by addition of hydrogen fluoride to acetylene (see Fluorine COMPOUNDS, ORGANIC, POLY(viNYL FLUORIDE)). 

Analytical Methods. A classical and stiU widely employed analytical method is iodimetric titration. This is suitable for determination of sodium sulfite, for example, in boiler water. Standard potassium iodate—potassium iodide solution is commonly used as the titrant with a starch or starch-substitute indicator. Sodium bisulfite occurring as an impurity in sodium sulfite can be determined by addition of hydrogen peroxide to oxidize the bisulfite to bisulfate, followed by titration with standard sodium hydroxide (279). 

Poly(vinyl fluoride) was first introduced in the early 1960s, in film form, by Du Pont under the trade name Tedlar. Details of the commercial method of preparing the monomer have not been disclosed but it may be prepared by addition of hydrogen fluoride to acetylene at about 40°C. 

Chloro-1,3-butadiene (chloroprene) is the monomer from which the elastomer neoprene is prepared. 2-Chloro-1,3-butadiene is the thermodynamically controlled product formed by addition of hydrogen chloride to vinylacetylene (H2C=CHC=CH). The principal product under conditions of kinetic control is the allenic chloride 4-chloro-1,2-butadiene. Suggest a mechanism to account for the formation of each product. 

Shortly thereafter, Knorr reported that combining ammonia or primary amines with 1,4-dicarbonyls furnished substituted pyrroles (see Section 2.2), and Paal produced thiophenes by addition of hydrogen sulfide with 1,4-dicarbonyls. ... 

Closely related to the concept of chirality, and particularly important in biological chemistry, is the notion of prochirality. A molecule is said to be prochiral if can be converted from achiral to chiral in a single chemical step. For instance, an unsymmetrical ketone like 2-butanone is prochiral because it can be converted to the chiral alcohol 2-butanol by addition of hydrogen, as we ll see in Section 17.4. 

In most cases, both hydrogen atoms are added to the same face of the double bond (syn addition). If hydrogenation occurs by addition of hydrogen in two steps, as... 

The reduction to methoxy-hydrido species (7) is thought to proceed via loss of CO from the dicarbonyl complex followed by addition of hydrogen to give the dihydrido carbonyl species (9). The next step suggested (37) is hydride transfer to the carbonyl carbon to give a formyl species in which both the carbonyl carbon and the carbonyl oxygen coordinate to the metal center, i.e., 10 ... 

Table 3. Relative Enthalpies (298 K, in kcal/mol) of Triplet Phenylnitrene (31 b), Triplet 3-Pyridylcarbene (3lc), a and Pairs of Molecules Formed from them by Addition of Hydrogen Atoms b...

The other reactions of the aldehydes, which are extraordinarily reactive substances, need only he mentioned here. Such reactions are reduction to alcohols, formation of hydrazones, oximes, semicarbazones, bisulphite compounds, acetals and cyanohydrins (by addition of hydrogen cyanide). 

By reduction of aldehydes and ketones Aldehydes and ketones are reduced to the corresponding alcohols by addition of hydrogen in the presence of catalysts (catalytic hydrogenation). The usual catalyst is a finely divided metal such as platinum, palladium or nickel. It is also prepared by treating aldehydes and ketones with sodium borohydride (NaBH4) or lithium aluminium hydride (LLAIH4). Aldehydes yield primary alcohols whereas ketones give secondary alcohols. 

Entries 4 and 5 in Scheme 2.1 depict acid-catalyzed aldol reactions. In entry 4, condensation is accompanied by dehydration. In entry 5, a /i-chloroketone is formed by addition of hydrogen chloride to the enone. 

Initiation by the combination of an alkyl halide and Lewis acid can be achieved by using a hydrogen halide and a Lewis acid. The alkyl halide is produced in situ by addition of hydrogen halide to monomer, followed by reaction with the Lewis acid. 

When 176 is treated with hydrochloric acid it gives the intermediate acyclic structure 265, which decomposes to sulfonyl isothiocyanates, isothiocyanates, and chlorformamidines. Solvolysis of 155 with ethanol, followed by addition of hydrogen bromide, leads to 266. Base hydrolysis of 156 leads to the zwitterionic structure 267. ... 

Synthesis from (3-Pinene. Pyrolysis of /3-pinene yields myrcene, which is converted into a mixture of predominantly geranyl, neryl, and linalyl chloride by addition of hydrogen chloride in the presence of small amounts of catalyst, e.g., copper(I) chloride and an organic quaternary ammonium salt [29]. After removal of the catalyst, the mixture is reacted with sodium acetate in the presence of a nitrogen base (e.g., triethylamine) and converted to geranyl acetate, neryl acetate, and a small amount of linalyl acetate [30]. 

Hydroquinone forms DNA adducts in the peroxidase-containing promyelocytic HL-60 cell line this process is enhanced by addition of hydrogen peroxide or cumene hydroperoxide (Levay Bodell, 1996), presumably because the hydroquinone is oxidized by a cellular peroxidase to a reactive, DNA-binding metabolite. 

Procedures for the preparation of the acetals of 3-nitropropanal 17have been reported from acrolein, by addition of hydrogen bromide in the presence of the... 

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