GB577581A - Improvements in or relating to the alkylation of organic compounds - Google Patents

Abstract

<PICT:0577581/IV/1> <PICT:0577581/IV/2> An organic compound containing a replaceable hydrogen atom is alkylated in liquid phase in the presence of a liquid alkylation catalyst in a mechanically agitated reaction zone by introducing the alkylating agent by multi-point ignition in finely-divided form through a large number, in excess of ten, of small feed openings, each of a diameter less than 1/4 inch, spaced throughout a region of the reaction zone confining at least about 1/10 th, and preferably about 1/4 or more, of the volume of the agitated mixture to prevent local accumulation of unreacted alkylating agent. The feed openings may be down to capillary size and spaced throughout 1/4 -\ba1/2 or more of the length of the recirculating passage where a mixer having a recirculating flow is used. The compound to be alkylated, such as an isoparaffin, may be injected in the same way, for example by mixing with the alkylating agent such as an olefin. Ratios of isoparaffin to olefin at the point of entry of 1500-2,000,000 : 1 or higher are obtainable. Contact times may be reduced, for example to 1-5 mins. Alkylation of isobutane, isopentane or isohexane with ethylene, propylene, butenes, pentenes, hexenes or higher olefins or olefin polymers, with alkyl esters such as chlorides, sulphates, fluorides, or aliphatic alcohols and ethers such as tertiary butyl or isopropyl alcohol or butyl ether, alkylation of normal paraffins, and of aromatics and hydroxy - aromatics such as benzene, toluene, xylene, phenol or cresol, for example of benzene with ethylene or chlorinated kerosene to produce ethyl benzene or "keryl benzene," are reactions specified. Alkylation catalysts include sulphuric, hydrofluoric, chlorsulphonic and fluorsulphonic acids, A1C13-hydrocarbon complexes and BF3nH2O. Multi-stage alkylation may be used with split olefin feed between the stages. A pump 14, Fig. 1, causes circulation of the reactor contents through and around an interior tube 13. The olefin, if desired together with part or all of the isobutane feed, is fed under pressure to the annular jacket 12, the inner wall of which is perforated or of porous material such as alundum so that multi-point injection occurs. A liner having 1/16 -\ba1/8 in. perforations spaced 1-6 ins. apart is satisfactory. Pressure pulsations applied to jacket 12 may be used to prevent clogging. The reactor contents are stratified, acid being recycled, and hydrocarbon neutralized, stabilized and fractionated, isobutane being also recycled. In modifications, Figs. 2 and 3 (not shown), the feed is injected through a perforated or porous cylinder pointed at its lower end and located within the interior tube through and around which the acid is circulated, additional cylinders being mounted outside this tube if desired, or annular injectors disposed above one another surround the tube, other injectors being located within it. The feed openings may be provided on one face or the edges only if desired, and the feed members are so spaced that alkylating agent from one has substantially reacted by the time the circulating stream reaches the next. In the pump and time tank reactor, Fig. 4, the olefin, preferably with part of the isobutane, is fed to chambers 127, 128 surrounding perforate pipes 123, 125 through which the acid reaction stream circulates. A combined alkylator and chiller 107 comprises a casing 131 through which a refrigerant such as propane is circulated. The circulating stream passes through tubes 132 between headers 130, 133, and the olefin is fed by lines 119, 120 through tubes 140 located within tubes 132 and connected by headers 138, 139. The tubes 140 are porous or perforated for passage of the olefin into the stream.