TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Components: The olefinic compound (II) has the formula CxFyHz, (where x is 12-b and b is 0-6, y is 2x-z, and for x/2 and 2x/3 equals integers then z is 2x/3; for x/2 and 3x/4 equals integers then z is 3x/4; for x/2 not equal to integer then z is x-2; for x/2 and x/5 equals integers then z is x-3). (I) is either a saturated compound obtained by reacting hydrogen fluoride with (II) or (II) is obtained by reduction with hydrogen. (I) is organic rankine cycle system, water, silicones, aliphatic hydrocarbons, cyclic hydrocarbons, aromatic hydrocarbons, olefins, hydrofluorocarbons, hydrofluoroethers, perfluoroethers, alcohols, ketones, fluorinated ketones, fluorinated alcohols, esters or phosphate esters. Preferred Process: The process further comprises: recycling the liquid phase working fluid from step (d) to step (a) through a pump; a liquid surge tank disposed between the condenser and the pump; and a secondary heat exchanger loop (comprises passing a secondary fluid in communication with both (A) and the process to produce (III), and transferring (III) from the process to the secondary fluid, (which further transfers (III) from the secondary fluid to the liquid phase working fluid) disposed between (A) to produce (III). In the process (III) is fuel cells, internal combustion engines, internal compression engines, external combustion engines or turbines. The secondary fluid is atleast one high-boiling point fluid, which is glycols, silicones or essentially non-volatile fluids. In the process the production of (III) is at least in one industries such as oil refineries, petrochemical plants, oil and gas pipelines, chemical industry, commercial buildings, hotels, shopping malls, supermarkets, bakeries, food processing industries, restaurants, paint curing ovens, furniture making, plastics molders, cement kilns, lumber kilns, calcining operations, steel industry, glass industry, foundries, smelting, air-conditioning, refrigeration or central heating. SPECIFIC COMPOUNDS - The use of 17 compounds (I) is specifically claimed e.g. 1,1,1,2,2,4,4,4-octafluorobutane, 2-trifluoromethyl 1,1,1,3,3-pentafluoropropane, 1,1,2,2,3,3,4,4-octafluorobutane, 1,1,1,2,2,3,3,4,4,5,5-undecafluoropentane or 1,1,1,2,3,4,4,5,5,5-decafluoropentane.