The intercalation of octadecyl amine (ODA) into the catalytically important VOHPO(4)(.)4H(2)O, VOHPO(4)(.)0.5H(2)O, VOPO4.2H(2)O and VOHPO(3)(.)1.5H(2)O phases has been found to give rise to mesolamellar phases with basal spacings of 32.8, 36.3, 30.0 and 36.2 Angstrom, respectively. It is shown from FTIR and CP-MAS NMR studies that considerable disorder in the alkyl tail of the intercalated ODA is introduced due to the internal methylene groups assuming gauche conformations. Consequently, the observation that the interlayer spacing of the ODA intercalates is lower than that expected from a fully stretched ODA molecule can be ascribed to the fact that the gauche conformations of the internal methylene groups cause a shortening of the effective length of the molecule. This contradicts the postulation of tilted configurations of fully stretched all trans alkyl amine molecules made in earlier studies of alkyl amine intercalation in VPO phases. It is also observed that the extent of conformational disorder in the intercalated ODA molecules is dependent on the structure of the host VPO lattice with the highest conformational disorder in the ODA intercalate of VOHPO(4)(.)4H(2)O followed by the intercalates of VOHPO(4)(.)0.5H(2)O, VOPO(4)(.)2H(2)O and VOHPO(3)(.)1.5H(2)O. (C) 2004 Published by Elsevier B.V.