MUSTARD

See also:

• OILS (adopted from the Fr. oile, mod. huile, Lat. oleum, olive oil)

OILS  , organic chemical compounds of general formula R.NCS . They may be prepared by the action of carbon bisulphide on primary amines in alcoholic or ethereal solution, the alkyl dithio-carbamic compounds formed being then precipitated with mercuric chloride, and the mercuric salts heated in aqueous solution, 2R•NHZCS2CS/NHR HgC121RHNCS2J2Hg--HgS+H2S+2RNCS; —> \S•NH,R .-4 or the isocyanic esters may be heated with phosphorus pentasulphide (A . Michael and G . Palmer, Amer . Chem . Jour., 1884, 6, 257) . They are colourless liquids with a very pungent irritating odour . They are readily oxidized, with production of the corresponding amine . Nascent hydrogen converts them into the amine, with simultaneous formation of thio-formaldehyde, RNCS+4H=R•NH2+HCSH . When heated with acids to 100 C, they decompose with formation of the amine and liberation of carbon bisulphide and sulphuretted hydrogen . They combine directly with alcohols, mercaptans, ammonia, amines and with aldehyde ammonia . Methyl mustard oil, CH3NCS, melts at 35° C.and boils at 119° C .

Allyl mustard oil, C3HBNCS, is the

principal constituent of the ordinary mustard oil obtained on distilling black mustard seeds . These seeds contain potassium myronate (C1oH,8NS20,0K) which in presence of water is hydrolysed by the myrosiri present in the seed, C15I-118NS2O10K = C6Hi206+KHSO4+CaHBNCS . It may also be prepared by heating allyl sulphide with potassium. sulphocyanide . It is a colourless liquid boiling at 150.7° C . I; combines directly with potassium bisulphite . Phenyl mustard of CBHGNCS, is obtained by boiling sulphocarbanilide with concentrated hydrochloric acid, some triphenylguanidine being formed at the same time . It is a colourless liquid boiling at 222° C . When heated with copper powder it yields benzonitrile .