Yields from hydrogen-chloride

Dichloromethine cyanine 17 which can be obtained in high yield from phosgeniminium chloride (PI) and N,N-dimethylacetamide has proven to be a particularly versatile source of push-pull ynamines. Arylamines, however cyclise on the aryl group and 2,4-bis(dimethylamino)quinolines are the final products80). The intermediary ynamines can only be detected by the IR. The process is catalysed by traces of hydrogen chloride see also (5.3). 

The cyclohexylethyl radical appears to abstract hydrogen more rapidly from hydrogen chloride than from cyclohexane and more rapidly than it adds to ethylene to yield cyclohexylbutyl or higher molecular weight radicals. Chain termination presumably occurs by condensation or disproportionation of a pair of free radicals, or by any other of the chain-terminating reactions which normally occur. No attempt was made to isolate or identify the so-formed byproducts. 

Primary aromatic amines are alkylated somewhat more cleanly e.g., N-benzylaniline is obtained in 95% yield from benzyl chloride and 4 equivalents of aniline in the presence of 1.25 equivalents of sodium hydrogen carbonate 475 with a smaller excess of aniline the tertiary base becomes the main product. 

Thiocarboxylic acids are obtained by acylation of hydrogen sulfide (cf. page 642). For example, thiobenzoic acid is formed (61-76% yield) from benzoyl chloride and potassium hydrogen sulfide,426 and thioacetic acid (74% yield) when hydrogen sulfide is passed into acetic anhydride.427,428 This method can also be applied to other anhydrides.429... 

In an attempt to produce hydrogen azide with a volatile acid, hydrochloric acid gas was at room temperature passed through a column packed with dry sodium azide the method reportedly [33] gave a poor yield, and hydrogen chloride had to be removed from the product. 

In the process, the chlorine radicals abstract hydrogens and form HCl. The quantum yield of hydrogen chloride from this reaction is hci = 0.11 [556]. This indicates that only 1 in every 100 photons that are absorbed causes the dehydrochlorination and is followed by formation of polyenes. It led to the conclusion that a photochemical process must take place between the polyene sequences and HCl [556, 557]. 

In a 1500 ml. round-bottomed flask, carrying a reflux condenser, place 100 g. of pure cydohexanol, 250 ml. of concentrated hydrochloric acid and 80 g. of anhydrous calcium chloride heat the mixture on a boiling water bath for 10 hours with occasional shaking (1). Some hydrogen chloride is evolved, consequently the preparation should be conducted in the fume cupboard. Separate the upper layer from the cold reaction product, wash it successively with saturated salt solution, saturated sodium bicarbonate solution, saturated salt solution, and dry the crude cycZohexyl chloride with excess of anhydrous calcium chloride for at least 24 hours. Distil from a 150 ml. Claisen flask with fractionating side arm, and collect the pure product at 141-5-142-5°. The yield is 90 g. 

The apparatus required is similar to that described for Diphenylmelhane (Section IV,4). Place a mixture of 200 g. (230 ml.) of dry benzene and 40 g. (26 ml.) of dry chloroform (1) in the flask, and add 35 g. of anhydrous aluminium chloride in portions of about 6 g. at intervals of 5 minutes with constant shaking. The reaction sets in upon the addition of the aluminium chloride and the liquid boils with the evolution of hydrogen chloride. Complete the reaction by refluxing for 30 minutes on a water bath. When cold, pour the contents of the flask very cautiously on to 250 g. of crushed ice and 10 ml. of concentrated hydrochloric acid. Separate the upper benzene layer, dry it with anhydrous calcium chloride or magnesium sulphate, and remove the benzene in a 100 ml. Claisen flask (see Fig. II, 13, 4) at atmospheric pressure. Distil the remaining oil under reduced pressure use the apparatus shown in Fig. 11,19, 1, and collect the fraction b.p. 190-215°/10 mm. separately. This is crude triphenylmethane and solidifies on cooling. Recrystallise it from about four times its weight of ethyl alcohol (2) the triphenylmethane separates in needles and melts at 92°. The yield is 30 g. 

The reason for this is that reaction (i) is usually much slower than (ii) and (iii) so that the main reaction appears to be (Iv) (compare the preparation of tertiary butyl chloride from tertiary butyl alcohol and concentrated hydrochloric acid, Section 111,33). If the reaction is carried out in the presence of P3rridine, the latter combines with the hydrogen chloride as it is formed, thus preventing reactions (ii) and (iii), and a good yield of the ester is generally obtained. The differentiation between primary, secondary and tertiary alcohols with the aid of the Lucas reagent is described in Section III,27,(vii). 

Phenylpropanolamine. - With catalyst prepared as previously described from 0.5g of palladium chloride and 3g of charcoal, it was possible to reduce two portions of 9.8g of isonitrosopropio-phenone (0.06 mol), dissolved in 150 cc. of absolute alcohol containing 7. Og of hydrogen chloride, to phenylpropanolamine in from 145 - 190 minutes with yields of the isolated chloride from 9.4g to 11. Og, or 84 to 98% of the theoretical. After recrystallization from absolute alcohol the salt melted at 191°. The free base was obtained by treating an aqueous solution of the hydrochloride with alkali on cooling, the liberated amino alcohol solidified and after recrystallization from water melted at 103°."... 

In the now-obsolete furfural process, furfural was decarboxylated to furan which was then hydrogenated to tetrahydrofuran (THF). Reaction of THF with hydrogen chloride produced dichlorobutene. Adiponitrile was produced by the reaction of sodium cyanide with the dichlorobutene. The overall yield from furfural to adiponitrile was around 75%. 

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