Dialkylcarbonate compounds (A) are new. Dialkylcarbonate compounds (A) of formulae (R 1>O-CO-OR 2>) (I), (R 3>O-CO-OR 4>) (II), (R 5>O-CO-OR 6>) (III) and (R 7>O-CO-OR 8>) (IV), are new. R 1>2-propyl-1-heptyl or 2-ethyl-1-butyl R 2>, R 4>, R 5>linear, branched or cyclic 1-22C hydrocarbon residues or 0-3 double bonds R 3>isodecyl residue, neodecyl residue, isoundecyl residue, isododecyl residue, isotridecyl residue, 2-pentylnonyl residue, 2-hexyldecyl residue, 2-heptyl undecyl-residue, isostearyl residue, 2-octyldodecyl residue, 2-butyl-1-octyl residue or 2-ethyl-1-hexyl residue R 6>more than 12C branched hydrocarbon residues or 0-3 double bonds R 7>branched 3-22C hydrocarbon residue or 0-3 double bonds and R 8>branched 1-22C hydrocarbon residue or 0-3 double bonds. Provided that: R 3> is not equal to R 4>, and R 7> is not equal to R 8>.