The invention provides a process for the preparation of 2,3,3,3-tetrafluoropropene (1234yf), the process comprising: (a) contacting 1,1,2,3,3,3-hexafluoropropene (1216) with hydrogen in the presence of a hydrogenation catalyst to produce 1,1,2,3,3,3-hexafluoropropane (236ea); (b) dehydrofluorinating 236ea to produce 1,2,3,3,3-pentafluoropropene (1225ye); (c) contacting 1225ye with hydrogen in the presence of a hydrogenation catalyst to produce 1,2,3,3,3-pentafluoropropane (245eb); and (d) dehydrofluorinating 245eb to produce 1234yf, wherein steps (a) and/or (c) is carried out with a diluent gas stream that comprises an excess of one or both of the feedstocks 1216 and/or 1225ye, respectively.