A process for preparing monoesters comprises the step of reacting at least one diol with at least one carboxylic acid in a biphasic solvent system, the carboxylic acid being sufficiently water soluble to allow esterification to occur, and the biphasic solvent system comprising water and at least one aprotic solvent in which the resulting monoester has greater solubility than in water.
Diamine compounds, which in particular are useful as precursors for the production of liquid crystal alignment layers, represented by general formula (I), wherein A
1
represents an organic group of 1 to 40 carbon atoms; A
2
represents a hydrogen atom or an organic group of 1 to 40 carbon atoms.
Diamine compounds, which in particular are useful as precursors for the production of liquid crystal alignment layers, are represented by the general formula I:
wherein
A
1
represents an organic group of 1 to 40 carbon atoms;
A
2
represents a hydrogen atom or an organic group of 1 to 40 carbon atoms.