Patent GB-656168-A (GB)
Title: A process for the preparation of secondary 1, 3-alkenediamines
IPC: C07C209/60
Filed: 1948-07-07
Abstract: Secondary 1,3-alkene diamines are made by reacting an aliphatic alpha, beta-unsaturated aldehyde with an aliphatic or cycloaliphatic primary mono-amine containing at least 3 carbon atoms or with a mixture of such amines at a temperature not exceeding 20 DEG  C., the amine being in substantial molar excess, preferably at least 2 mols. per mol. of aldehyde, e.g. 3.5-8 mols. per mol. being used.  The process conforms with the equation (R1)2-C=C(R1)CHO+2RNH2= R-NH-C(R1)2-C(R1)=CH-NH-R+H2O wherein R is an aliphatic or cycloaliphatic group containing at least 3 carbon atoms and R1 is H or an alkyl group, many of which are specified.  Preferably, R1 is H or lower alkyl and amongst many aldehydes specified the following may be mentioned: acrolein, alpha-ethylacrolein, alpha tert butylacrolein, alpha-isopropyl-beta-ethyl acrolein and beta - ethyl - beta - propylacrolein.  Particularly preferred aldehydes are those of formula CH2=C(R11)CHO, where R11 is H or an alkyl, preferably a lower alkyl, group.  Amines specified include propylamine, tertbutylamine, 1,3-diethylpentylamine, eiconylamine, cyclopentylamine, cyclohexylamine, 2-cyclohexylethylamine and triethylcyclopentylamine, unsaturated amines, e.g. allylamine, 2-propynylamine, cyclohexenylamine and 3-cyclohexenylbutylamine are also specified. Preferred groups of compounds made are the N N1 - dialkyl - 1 - alkene - 1 3 - diamines, N,N1-dialkyl-1,3-propenediamines and N,N1-dialkyl-2-alkyl-1,3-propenediamines and the N,N1-bis-(2 - alkenyl) - 1 - alkene - 1,3 - diamines, many of which classes are specified.  A temperature range of - 30 DEG  to +20 DEG  C. is mentioned.  An inert solvent medium may be used particularly when both reactants are solid.  Solvents specified are ethers, esters, saturated and aromatic hydrocarbons.  The reaction is favoured by the absence of water and the reactants may be employed anhydrous or desiccating agents, particularly non-acidic, e.g. anhydrous potassium and sodium carbonate, calcium and magnesium oxide, sodium sulphate or activated alumina may be added.  Reaction times of 1/2 -12 hours are instanced, the product preferably being recovered by distillation at reduced pressure.  By reacting the aldehyde with a mixture of amines products are obtained in which the terminal groups R are different, together with those in which both R's are the same. Alternatively, R's may be obtained different by reacting the product in which R's are the same with an aliphatic or cycloaliphatic primary mono-amine to effect substitution of amino groups.  The products may be saturated by hydrogenation.  In examples: (1) isopropylamine containing anhydrous potassium carbonate is cooled to 5-10 DEG  C., acrolein added over a period of 2 hours when the reaction product is filtered and distilled at reduced pressure to give N,N1-diisopropyl-1,3-propenediamine; (2) methacrolein is added to isopropylamine cooled to 0-8 DEG  C. and N,N1 - diisopropyl - 2 - methyl - 1,3 - propenediamine recovered by vacuum fractional distillation; (3) acrolein is added to 1,3-dimethylbutylamine containing anhydrous potassium hydroxide and N,N1-bis-(1,3-dimethylbutyl)-1,3-propenediamine obtained, reaction conditions being as in (1) and in (4) the product of (1) is refluxed with 1,3-dimethyl-butylamine, isopropylamine being removed as formed through a fractionating column and on vacuum fractionation of the remainder N-(1,3-dimethyl-butyl)-N1-isopropyl-1,3-propenediamine is obtained, it being stated that the latter compound is also obtained by fractionation of the product of the reaction between acrolein and an equimolar mixture of 1,3-dimethylbutylamine and isopropylamine.