GB679411A - Improvements in or relating to methods for fusion reactions - Google Patents

Abstract

Fusion reactions of alkali metal arylsulphonates are effected by maintaining within an upper zone the upper level of a fluid body containing a fused alkali metal hydroxide or phenolate, passing (preferably by gravity) a portion of said fluid body from the upper zone to the lower portion of an elongated reaction zone which is vertical or inclined to the vertical at an angle not exceeding 45 degrees, heating the fluid body in passage by indirect heat exchange with a higher temperature heat source and introducing an aqueous solution containing at least an alkali metal arylsulphonate into the heated fluid body passing into the lower portion of the elongated zone whereby the additional heat acquired by the fluid body is used to convert the water of the aqueous solution to superheated steam and effect the fusion reaction, and whereby the rapid rise of the superheated steam up through the elongated zone causes the fluid body to pass up through the elongated zone and return to the upper zone. The process is applicable to the preparation of alkali metal phenolates or of steam-volatile phenols in accordance with one of the equations <FORM:0679411/IV (b)/1> , or <FORM:0679411/IV (b)/2> , wherein Ar represents an aryl radical and M an alkali metal, and the value of x is zero, one or a positive fraction between these values. In carrying out reaction (2), the fluid body may consist of a fused alkali metal phenolate and an alkali metal sulphite in the ratio of 1-6 (preferably 1.5-3.0) moles of the former to 1 mole of the latter, at a temperature of 355-420 DEG C. (preferably 370-400 DEG C.), the steam-volatile phenol being withdrawn with the steam from a point above the level of the fluid fusion mass. To keep the volume and composition of the latter substantially constant, a portion thereof may be continuously withdrawn, quenched in water and filtered to remove alkali metal sulphite, the resulting aqueous solution of alkali metal phenolate being returned to the reaction zone in admixture with the feed solution of alkali metal arylsulphonate. Suitable forms of apparatus are described with drawings (see Group III). Examples describe the preparation of phenol and sodium phenate from sodium benzenesulphonate. Reference is also made to the production of cresols, xylenols and naphthols and their alkali metal compounds from the appropriate alkali metal arylsulphonates.ALSO:Apparatus for carrying out fusion reactions of alkali metal arylsulphonates <PICT:0679411/III/1> <PICT:0679411/III/2> comprises an elongated reaction zone which is vertical or inclined to the vertical at an angle not exceeding 45 degrees and which opens at the upper end into an upper zone containing fused reaction mixture, means for passing part of this fused material (preferably by gravity) to the lower portion of the elongated zone and for heating it during passage, and means for introducing an aqueous feed solution and, if desired, steam, into the lower portion of the elongated zone, whereby the additional heat acquired by the fused material is used to convert the water of the aqueous solution to superheated steam and effect the fusion reaction, and whereby the rapid rise of the superheated steam carries the fused material up through the elongated zone and back to the upper zone. Means may also be provided for withdrawing excess of fused material and for carrying away steam with, in some cases, steam-volatile phenols produced by the reaction. In the form of apparatus shown in Fig. 1, the upper zone 1 is connected to a header chamber 5 beneath the elongated zone 3 by conduits 4 heated by hot gases from a burner 11. In a modification, the elongated zone is placed to one side and the lower portions are bent round so as to pass directly into the lower portion thereof. In a further modification, Fig. 5, the heating means consists of horizontal or inclined heat-exchange tubes 54, and the elongated zone 53 is bent horizontally at the upper end and enters the upper zone 51 tangentially to the wall thereof.