A systematic study on methane hydrate formation and dissociation was carried out in presence of liquid hydrocarbon promoters namely tetrahydrofuran (THF) and tert-butylamine (t-BuNH2). Mixed hydrates with THF/t-BuNH2 (mole fraction x = 0.05) were of sll symmetry. The hydrate formation/dissociation of mixed hydrates with x = 0.033 and 0.0056 were complex with co-existence of sll and sl structures. We observed the hydrate formation in two steps, hydrates in the first stage (similar to T = 295 K) were mostly with sll and in the second stage (similar to T = 275 K) were with sl structure, corroborating the literature. However, dissociation pattern of the hydrates formed in second stage significantly differ from pure methane hydrates and the above two liquid hydrocarbons show considerable promoter effect for 51 hydrates. (C) 2011 Elsevier B.V. All rights reserved.