Butylketene dimer

Butane, 1,4-diiodo-, 30, 33 2-Butanone, 3-acetamido-, 33,1 n-BuTYLACETYLENE, 30, IS tert-Butyl alcohol, 30, 19, 20 32, 20 ierl-Butylbenzene, 32, 91 n-Butyl bromide, 30, 16 tert-Butyl hypochlorite, 32, 20 n-Butyl iodide, 30, 34 Butylketene dimer, 31, 71 -ter -Butylphenyl salicylate, 32, 26 Butyrchloral, 33, IS Butyric acid, a, y-dicyano-o-phenyl-, ethyl ester, 30, 80... 

Other acid chlorides of the type RCH2COCl can be similarly dehydrochlorinated. For example, caproyl chloride (1.2 moles) was converted into di-w-amyl ketone, b.p. 98-102°/15 mm., in 60-71.5% yield. In this case, it was found preferable to remove the amine salt from the reaction mixture by washing with 2% sulfuric acid. The butylketene dimer was then extracted from the reaction mixture by washing with 5% sodium hydroxide solution the alkaline solution was acidified with sulfuric acid and steam-distilled. The oily layer in the distillate was separated and fractionated. 

Butylisoquinoline, 38, 61 Butylketene dimer, 31, 71 teri-Butyl 2-methylenedodecanoate,... 

StericaHy hindered or very electrophilic substituted ketenes, such as diphenylketene, di-Z rZ-butylketene [19824-34-17, and bis(trifluoromethyl)ketene, are quite stable as monomers. Ketenimines tend to polymerize. The dimerization of thioketenes results in 1,3-dithiacyclobutanones (6) (45), a type of dimer not observed with ketenes. 

Monoalkylketenes are also prone to dimerization, but dialkylketenes have longer lifetimes. The remarkably crowded and unreactive di-teri-butylketene 5 bears strong steric protection and was first prepared in 1960 from the acyl chloride using a strong base (Eqn (4.4)), and identified by the characteristic ketenyl IR absorption. The dehydrochlorination reaction has also been carried out with triethylamine as the base using ultrasound in 86% yield or by reaction with neat tri- -butylamine at 80 °C, also in 86% yield. The use of the aldehyde i-Bu2CClCH=0 as an alternative precursor to 5 by an elimination reaction has also recendy been reported. This ketene is stable indefinitely as a neat liquid and reacts slowly with and there is no... 

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