GB1228831A - - Google Patents

Abstract

1,228,831. Chemical reaction vessels; polymerization of olefines. MICHELIN & .CIE (COMPAGNIE GENERALE DES ETABS MICHELIN). 1 May, 1968 [2 May, 1967], No. 20677/68. Heading B1X. [Also in Division C3] Chemical reactions, e.g. the polymerization and copolymerization of olefines and/or diolefines, are carried out in a tubular vessel 1 (Fig. 1) forming a closed path between a point 2 where one or more components of the reaction mixture are continuously introduced through inlet 11 into the vessel and a point 3 where the reaction mixture is continuously removed through outlet 25, the mixture flowing through the vessel being separated into doses 5 by balls 6 (e.g. hollow spheres of metal) which are carried through the vessel by the reaction mixture. Intervention stations are provided along the vessel for introducing catalyst, and for withdrawing and/or recycling reaction mixture. For example, catalyst may be introduced at station 12; agitation may be effected by withdrawing mixture through outlet 14 and returning it (together with fresh catalyst or fresh monomer) through inlet 15; at a third station 20 is recycled part of the mixture withdrawn through outlet 21; and at a fourth station 23 is withdrawn a sample for checking purposes. Parts of the tubular vessel 1 are surrounded by jackets 7 for temperature-regulating fluids. The balls 6 are moved from the outlet end of vessel 1 to partition 30 in the bore 27 of block 4 by means of piston 29, which has a hemispherical cavity 33 in its base. Both the pistons 28, 29 then move away from partition 30, liberating a ball which is then entrained by the feed mixture into the inlet of vessel 1. The pistons are actuated automatically. The reaction may be carried out in a cluster of straight parallel tubes 50 (Fig. 2) connected in series by semi-circular bends 60, the various intervention stations being located in the bends, e.g. as at injection point 15. Examples relating to the polymerization of butadiene, and the copolymerization of butadiene and styrene, using heptane as solvent and lithium butyl (with or without hexamethylphosphorotriamide) as catalyst, are given in the specification; and graphs showing the molecular-weight distribution of the products are included.