Metal formate dihydrate

Rubidium hydroxide, RbOH.—The hydroxide is formed by dissolving the metal in water, or by the action of barium hydroxide on rubidium sulphate. It is a very deliquescent substance, and is volatilized by heat. Its melting-point8 is 301° C., and its density9 3-203 at 11° C. The latent heat of fusion per mol. is 1-614 Cal.10 the heat of formation from the elements is 101-99 Cal.11 A monohydrate and a dihydrate have been described.12... 

Polymerization. Typically, the dihydric phenol (1 mole) and aqueous alkali metal hydroxide (2 moles) are mixed under an inert atmosphere in sulfolane and benzene. The water from the aqueous solution plus metal phenoxide formation is removed by distillation of a benzene-water azeotrope between 110° and 140°C. After water removal has been completed, the excess benzene is distilled off, the anhydrous salt in sulfolane cooled to 70°-80°C, and bis(4-chlorophenyl)-sulfone (I) added. The temperature is increased gradually to 200°C and held for four to five hours. Methyl chloride is bubbled in at the end of the polymerization to convert any terminal phenoxide groups to methyl ethers (10). 

The use of both LIU and HIU has been shown to increase the efficiency of the P-K reaction, which involves the formation of cyclopentenone from the annulation of a cobalt alkynyl carbonyl complex and an alkene. The use of low-power ultrasound, as for example, from a cleaning bath, although capable of producing intramolecular P-K reactions, generated relatively low cyclization yields. The motivation for the use of high intensity came from its ability, as previously described, to effectively decarbonylate metal carbonyl and substituted metal carbonyl complexes. Indeed, HIU produced by a classic horn-type sonicator has been shown to be capable of facile annulation of norbornene and norbornadiene in under 10 min in the presence of a trimethylamine or trimethylamine N-oxidc dihydrate (TMANO) promoter, with the latter promoter producing cleaner product mixtures. This methodology also proved effective in the enhancement of the P-K reaction with less strained alkenes such as 2,5-dihydrofuran and cyclopentene, as well as the less reactive alkenes -fluorostyrene and cycloheptene. The mechanism has been postulated to involve decarbo-nylation of the cobalt carbonyl alkyne, followed by coordination by the amine to the vacant coordination sites on the cobalt. 

The formation of DPQ not only reduces the yield of polymer but also degrades its quality. Thus, it is imporant to remove both the DPQ and metallic catalyst residues from the reaction solution because they could result in discoloration and degradation of resin while processing. In typical large scale operations, the reaction mixtures are usually treated with a combination of the dihydric phenol and a mild reducing agent, e.g. hydroquinol and sodium sulfite for 20-30 minutes to minimize the residues before isolation of the polymer (Figure 2.2.). 

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