Abstract: A heat exchanger having outer surfaces thereof coated with a hydrophilic coating layer. The hydrophilic coating layer essentially consists of a resin as a base, containing a colloidal silica. In the hydrophilic coating layer, part of silanol groups of the colloidal silica are chemically combined with part of hydroxyl groups of the resin. Due to this chemical combination, the colloidal silica undergoes change in its properties such that it has degraded adsorptivity, making smells less liable to attach to the colloidal silica.

Abstract: An optically active compound represented by the general formula (I) of:R--Z--COO--(Ph).sub.k --Ph(Y)--CO--(CH.sub.2).sub.m C*HE L (1)In the general formula (I); R is an alkyl or alkoxy group having 4 to 22 carbon atoms; Z is the one selected from the group consisting of --Ph--, --Ph(X)--, --Ph--Ph--, Ph(X)--Ph--, --Ph--cy--, --Ph(X)--cy-- and --py--Ph-- is a 1,4-substituted phenylene group; --Ph--Ph-- is a 4,4'-substituted diphenylene group; --cy-- is a trans-1,4-cyclohexane group, --py is 2,5-substituted pyrimide group; X is a halogen atom at the ortho-position to R; k is zero or 1, Y is the one selected from the group consisting of H, OH, halogen atoms and methyl group; C* is an asymmetric carbon atom; E is the one selected from the group consisting of methyl group, halogen atoms and CF.sub.3 ; L is an alkyl, aryl or aralkyl group having not more than 10 carbon atoms; and m is an integer of zero to 6 where m takes zero when Y is H and Z is --Ph-- or --Ph--Ph--.