The Knoevenagel reaction of aromatic aldehydes with malononitrile and ethyl cyanoacetate proceeds smoothly in the presence of carboxymethyl cellulose supported triethylenetetramine as catalyst in the 95% ethanol to afford the desired E-isomers of the corresponding alkenes in yield of 74%～96% and good purity. The results confirm that the catalyst can offer definite advantages of good activity , easy separation, mild reaction condition and high yields. Moreover, it can be reused for not less than 5 runs.
