As reported by Lee et al for gas

Tetrahydrofuran (THF), a well-known thermodynamic hydrate promoter, can be added to the system in order to significantly reduce the equilibrium pressure for gas hydrate formation at a specified temperature [3], [7], [15], [39], [43], [44], [45] and [46]. However, THF has several drawbacks for its actual usage in the process, because it is highly volatile and toxic [35] and [47]. THF can be entrained and mixed with gas mixtures retrieved from the gas hydrate phase after dissociation, indicating that further processes for purification of the gas phase, and for recovery of THF, might be needed.