Cupric benzoate

Copper salt dihydrate, C 4H,0CuO4.2H2O, cupric benzoate. Light blue, cryst powder. Slightly soluble in cold water, more in hot water sol in ale or in dil acids with separation of benzoic acid. 

A 50 ml flask equipped with a reflux condenser and a thermometer was charged with thiophenol (10 mmol), the iodonium salt (20 mmol), tributylamine (2.22 g, 10 mmol) and cupric benzoate (0.2 g). The mixture was stirred and heated at 120-125°C for 3 h under nitrogen. On cooling, the reaction mixture was washed with anhydrous ether (3 x 50 ml) to remove the iodoarenes. The residue was recrystallized from ethanol to give triarylsulphonium salts (48-87%). Similar conditions with slight variations were used when sulphides were the starting material. 

The oxidation of benzoic acid by divalent copper carried out by heating cupric benzoate to 210-260 C in high-boiling liquids furnishes 73-100% of salicylic acid [361]. 

Table XX. Some Proposed Mechanisms for the Decomposition of Cupric Benzoate...

In the trihydrate of cupric benzoate there are chains CUX2B of the type illustrated in Fig. 25.16(c), p. 903, in which X is H2O and B is the benzoate group, —0C(CgHs)0- the remaining H2O and CgHsCOO" ions are accommodated between the chains. 

The conversion of benzoic acid to phenol in the presence of cupric benzoate has formed the subject of various interpretations. The most widespread assumes the formation... 

Cupric benzoate decarboxylates thermally with the production of cuprous benzoate and phenyl benzoate. It is regenerated by the action of oxygen and benzoic acid. Phenol. is obtained by the steam hydrolysis of phenyl benzoate. 

Oxidation of camphene. When camphene (1) is allowed to react in acetonitrile at 80° with /-butyl perbenzoate and catalytic amounts of cuprous chloride and cupric benzoate, mainly alcohols are obtained after saponification (237o yield) rather than ethers (87o yield). The two principal alcohols are (2) and (3) the former is identical to nojigiku, isolated originally from a Japanese chrysanthemum. 

Before discussing Breslow s results, which involve remarkable specificity, it seems worthwhile to discuss a monocyclization reaction described by Julia (Scheme 142). Treatment of the diene 380 with benzoyl peroxide, cuprous chloride, and cupric benzoate in acetonitrile at 80 C affords the (Cy5) product 383 in 35% yield and less than 2% of the (Cy6) product. Thus a significant proportion of the benzoyloxyl radicals add to 380 at the more substituted double bond giving radical 381, which then cyclizes to the (Cy 5) radical 382. 

The first step is a liquid phase air oxidation of toluene to benzoic acid. Air and toluene are fed continuously into the base of an autoclave containing benzoic acid and a cobalt acetate-manganese acetate catalyst at 110—150°C and about 3 atmospheres. About 50% of the toluene is converted per pass. The unreacted toluene is removed and recycled and the residual crude benzoic acid is purified by distillation or crystallization. In the second step benzoic acid, containing cupric benzoate as catalyst and magnesium benzoate as promoter, is heated to 230—240°C. Steam and air are passed into the melt. Phenol and benzoic acid are vaporized continuously and are separated by distillation. The overall yield of phenol is 70-75%. 

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