Phenolic Structure and Colour in Mannich Reaction Products

Abstract

Mannich reactions have been carried out with a variety of model alkylphenols and dimethylamine, methylamine, and diethylenetriamine to trace the origin of persistent coloured products occurring in related reactions with pentadeca(e)nylphenol and 4-tert-alkylphenols. It was found to be attributable to the presence of resorcinolic impurities.

Anionic Surfactants Synthesised from Replenishable Phenolic Lipids

“…In previous work [3] on the reaction of ethylene oxide with saturated cardanol (3-pentadecylphenol) and with cardol a range of oligomeric ethoxylates (2, m = 1-40) (Scheme 1), was obtained but the first member of the series (2, m = 1, n = 0) was formed in very small proportion. It was more easily derived by the reaction of saturated cardanol with chloroacetonitrile, hydrolysis and hydride reduction or from saturated cardanol and ethyl chloroacetate followed by reduction [9].…”

“…The crystalline material which separated was filtered (ethylene carbonate), washed with hexane and the filtrate kept at 0°C to afford the product as a white crystalline solid 0.33 g, 18%; a further crop of product (0.50 g) was separated from the filtrate kept at 0°C (total yield (46%); mp 45-46°C; (lit. 4 (1-Hydroxy-3-carbethoxymethoxy-5-pentadecylphenol), (5, n = 0) To 5-pentadecylresorcinol (1.00 g, 3.12 mmol) in refluxing benzene (40 cm 3 ) containing potassium carbonate, ethyl bromoacetate (0.52 g, 3.11 mmol) in benzene (10 cm 3 ) was added dropwise over 4 h. The mixture was refluxed for a further 20 h, then cooled and filtered and the filtrate concentrated to give an oil which was purified by column chromatography (2% ethyl acetate in chloroform) to give the product, 0.80 g, (34%); d H (500 MHz), CDCl 3 To methanolic potassium hydroxide (1.7 cm 3 ) prepared from potassium hydroxide (1.30 g, 23.2 mmol) in methanol (10 cm 3 ), 3-pentadecylphenol (1, n = 0) (1.0 g, 3.28 mmol) was added and the methanol evaporated to leave a dry solid. This was suspended in dichloromethane (10 cm 3 ) and ethylene sulfate (0.50 g, 4.03 mmol) added.…”

“…TLC examination showed a single band and no 3-pentadecylphenol. The mixture was diluted with water, warmed to give a solution and cooled to yield a pale cream crystalline product which was filtered and washed with a small volume of water; d H (300 MHz), D 2 O) 7.94 (1H, s, HAr), 6 3 ), and contained primarily the ethoxylates of saturated cardanol (2, m = 1, n = 0) and of cardol (4, m = 1, n = 0).…”

“…Thus, cationic compounds [2,3], non-ionic [4,5] and anionic compounds (4 and Tyman and Durrani, Unpublished data) have been synthesised, although members of the latter have not been well characterised [6]. Technical CNSL which is obtained by the industrial process of thermal decarboxylation [1] of the natural cashew nut, contains the component C15 phenols cardanol (1, 65-70%), cardol (3, 15-20%), 2-methylcardol (5%) and polymeric material.…”

The Structures of some Coloured Compounds from Dihydric Phenols and Alkylamines†

“…In an investigation of the Mannich reaction of a variety of phenols, the formation of coloured by-products was observed and was traced to the reaction of certain 1,3-dihydric phenols with organic bases. 1 Coloured compounds were found to result from the reaction of 1,3-dihydroxybenzenes (resorcinols) having alkyl and alkenyl substituents, notably cardanol, 2 with primary, secondary, primary/secondary (diethylenetriamine) and even tertiary amines. The reaction of ammonia with resorcinols, giving orceine and litmus compounds, has been studied in great detail.…”