Lead thiocyanate

The a-thiocyanatoketones are easily obtainable from a-halocarbonyl compounds and metal thiocyanates (sodium, potassium, barium, or lead thiocyanate) (416, 484, 519, 659) in an alcoholic solution. Yields ranged from 80 to 95%. They are very sensitive substances that isomerize when reacted upon by acids, bases, or labile hydrogen and sulfur compounds. 

Blei-rhodanid, n, lead thiocyanate, -rohr, n., -rShre, /. lead tube or pipe, -rostprozess, m. lead roasting, -rot, n. red lead, minium, -safran, m. orange lead, -salbe, /. (Pharm.) lead ointment, cerate of lead subacetate, -salpeter, m. lead nitrate, -salz, n. lead salt, specif, lead acetate, -sammler, m. lead accumulator lead storage battery. 

The explosive properties of lead thiocyanate have found limited use. 

Lead thiocyanate was made by stirring together a solution of 45 g. (1.37 moles) of lead nitrate in 360 ml. of boiling water with a solution of 266 g. (2.74 moles) of potassium thiocyanate in 140 ml. of boiling water. The mixture was cooled to room temperature, and 437 g. (99%) of lead thiocyanate was separated by filtration and air-dried. 

A. Phenylacetyl isothiocyanate. Twenty-five grams (0.16 mole) of phenylacetyl chloride (Note 1), 100 ml. of benzene, and 53 g. (0.16 mole) of lead thiocyanate (Note 2) are placed in a 1-1., three-necked, round-bottomed flask equipped with a mechanical stirrer and a reflux condenser. The stirrer is started and the mixture is refluxed for 5 hours. A small amount of activated charcoal is added, and refluxing is continued for 5 minutes. The warm mixture is filtered through a Buchner funnel under suction (Note 3), and the solid on the filter is washed with two 50-ml. portions of benzene. The solvent is removed from the filtrate under reduced pressure, and the residue is distilled at once to yield 17.5— 22.7 g. (61-79%) of phenylacetyl isothiocyanate, b.p. 83-91° at about 0.3 mm. It is a colorless liquid that rapidly darkens on standing (Notes 4 and 5). 

Ibid, pp 134-44 (Initiation of lead thiocyanate-potassium chlorate mixts) Ad 130) T.Z. 

Lead Thiocyanate (Lead Sulfocyanate, Lead Rhodamide). Pb(SCN)2, mw 323.38, white, odorless pdr, mp (dec 190—95°), d 3.82g/cc sol in about 200p cold, 50p boiling w sol in alkali hydroxide and thiocyanate solns. May be prepd by the action of a sol Pb salt (acetate or nitrate) on K thiocyanate (Ref 1). It has found extensive use in stab priming and ignition mixts. Examples are 1) priming mixt Pb(SCN)2 25, Sb2S3 17, LA 5 KC103 53% ... 

LEAD THIOCYANATE Lead Sulfocyanate Poison, Class B 1 1 1 ... 

A usual method for the preparation of a solution of thiocyanogen is to treat lead thiocyanate with a dry ethereal solution of bromine cooled in ice. 

In many of its reactions, and in its molecular formula, thiocyanogen shows a close analogy with the halogens. Its molecular weight has been determined by the cryoscopie method, allowing a known weight of bromine to react with lead thiocyanate in the presence of bromoform,... 

The Fischer method7 for preparation of sugar isothiocyanates is general however, many modifications have been introduced, using, for example, nonpolar solvents and silver thiocyanate,29 33 lead thiocyanate,33 or ammonium thiocyanate,34 and potassium thiocyanate in acetonitrile in the presence of tetrabutylammonium hydrogensulfate.34 ... 

Previously, the reaction of 3,4,6-tri-0-acetyl-l,5-anhydro-2-deoxy-D-arabino-hex-l-enitol (D-glucal triacetate) (20) with lead thiocyanate in a mixture of acetic acid, acetic anhydride, and carbon tetrachloride had been reported by Igarashi and Honma.37 They observed formation of isothiocyanate 21 as the main product, accompanied by a mixture of four isomeric thiocyanates. 

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