Thiocyanates, molten

See also METAL THIOCYANATES, MOLTEN SALT BATHS... 

The chemistry of thiocyanate melts. D. H. Kerridge, Adv. Molten Salt Chem., 1975, 3, 249-273... 

According to an O.S. amendment sheet, the procedure as described [1] is dangerous because the reaction mixture (dicyanodiamide and ammonium nitrate) is similar in composition to commercial blasting explosives. This probably also applies to similar earlier preparations [2]. An earlier procedure which involved heating ammonium thiocyanate, lead nitrate and ammonia demolished a 50 bar autoclave [3], TGA and DTA studies show that air is not involved in the thermal decomposition [4], Explosive properties of the nitrate are detailed [5], An improved process involves catalytic conversion at 90-200°C of a molten mixture of urea and ammonium nitrate to give 92% conversion (on urea) of guanidinium nitrate, recovered by crystallisation. Hazards of alternative processes are listed [6],... 

A mixture of the nitrite with sodium thiocyanate explodes on heating [1], Preparation of a molten salt bath from 0.45 kg of potassium thiocyanate (reducant) and 1.35 kg of sodium nitrite (oxidant) led to a violent explosion on melting, which... 

See METAL THIOCYANATES Oxidants, MOLTEN SALT BATHS See other REDOX REACTIONS... 

The salt pipHSCN, known as piperidinium thiocyanate or piperidine hydrothiocyanate, has a melting point of 95 °C. When metal compounds are added to this molten salt, thiocyanate complexes of the metals are produced. For example, the following reactions can be carried out at 100 °C in the presence of an excess of the amine hydrothiocyanate ... 

See also MOLTEN SALT BATHS, METAL THIOCYANATES... 

If the ratio be unity, the concentrations of the solute in each solvent will be the same if the ratio be far removed from unity, a correspondingly large proportion of the solute will be found in the one solvent which can be utilized to extract the Soln. from the other solvent. E.g. ether will remove ferric chloride from its aq. soln., and since many other chlorides are almost insoluble in ether, the process is utilized in analysis for the separation of iron from the other elements the solubility of cobalt thiocyanate in ether is utilized for the separation of cobalt perchromic acid is similarly separated from its aq. soln. by ether molten zinc extracts silver and gold from molten lead the extraction of organic compounds from aq. soln. by shaking out with ether or other solvent is much used in organic laboratories. 

A mixture of the nitrite with sodium thiocyanate explodes on heating [1]. Preparation of a molten salt bath from 0.45 kg of potassium thiocyanate (reducant) and 1.35 kg of sodium nitrite (oxidant) led to a violent explosion on melting, which caused severe structural damage to the laboratory [2]. It was claimed that this could not have been foreseen from available information [2], but this was vigorously refuted [3,4]. Use of sand baths, rather than salt baths for laboratory heating purposes is to be preferred [5]. The relative lack of descriptive chemistry in modern curricula is cited as the major contributory factor to the general ignorance which led to the explosion [6],... 

Phthalic Acid or Phthalic Anhydride. Mixtures explode violently on heating.8 Sodium Amide. Addition of the nitrite to molten amide results in violent explosion.9 Sodium Thiocyanate. Mixture explodes on heating.6... 

As has already been pointed out, the Finkelstein reaction can be conducted in situ in the absence of solvents. For example, alkylations of purine and pyrimidine bases with alkyl halides and dimethyl sulfate have been carried out by solid/liquid phase-transfer catalysis in the absence of any additional solvent [48], as have cyanation of haloalkanes [49] and / -eliminations [50]. Noteworthy is the synthesis of glycosyl isothiocyanates by the reaction of potassium thiocyanate with molten glycosyl bromide at 190 °C [51]. 

Dinuclear complexes [M(SCN) (Ph2PO)2H ]2(M = Pd or Pt) have been prepared by metathetical reaction from the chloro-bridged dimers (see below).42 The X-ray structure (15) (see Table 1, p. 400) shows square-planar co-ordination around the Pd (N, S, 2 ) with an unusual symmetrically H-bonded anion [(Ph2PO)2H]. In view of the possibility of S- or N-bonding, molten thiocyanate is of some interest... 

Into a 250-ml., two-necked, round-bottomed flask equipped with a thermometer (Note 1) and leading to a condenser equipped with a distillation head and a receiver is placed 145 g. (1.5 mole) of potassium thiocyanate (Note 2). The system is evacuated to about 1 mm., and the flask is heated with a free flame until the temperature of the molten salt is in the 165-175° range (Note 3). After the flask has been heated for 15 minutes, it is cooled to room temperature and 88 g. (1.0 mole) of ethylene carbonate... 

Guanidine thiocyanate, prepared by passing ammonia into molten ammonium thiocyanate, is converted into the sulfate. The latter can be converted to the nitrate by the action of calcium nitrate. Gluud, Keller and Schultze, Ber. ges. Kohlentech. 4, 21 (1931) [C. A. 26, 2017 (1932)]. 

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