METHOD OF OBTAINING OLEFINS

摘要

1398802 Dehydrogenating C 3 -C 20 paraffins VYSKUMNY USTAV PRE ROPU A UHLOVODIKOVE PLYNY 15 Aug 1973 [15 Aug 1972] 38611/73 Heading C5E Olefins are produced by catalytically dehydrogenating C 3 -C 20 alkanes at 400-650‹ C. and a space velocity of 500-5000 hr.-1, where the product is either partially recycled through the catalyst bed or a plurality of catalyst beds are used in series. When the product is recycled the weight ratio of recycled product to. the feedstock entering the catalyst bed may be 0À1 : 1 to 4 : 1. When a series of 2 to 4 beds are provided the product is re-heated on leaving each bed except the last before entering the next bed. The dehydrogenation of C 6 -C 20 alkanes is preferably carried out in the presence of H 2 . The dehydrogenation of C 2 -C 5 alkanes is preferably carried out in the absence of H 2 and at 540-650‹ C. and a pressure of 1-2 kg./cm.2. The catalyst is preferably Pt or Cr in combination with an oxide of Mn, Sn, Sb or an alkaline metal supported on Al 2 O 3 . Examples describe the preparation of n-butene, C 10 -C 12 olefins and n-heptene.