GB414716A - A process for the separation of the crude resin obtained by extraction from kauri timber into light and dark coloured resinous products and apparatus therefor - Google Patents

Abstract

Crude resin obtained by extraction from Kauri timber with a solvent such as alcohol is purified by heating with a mixture of ethyl acetate and benzol or benzene. The crude resin, preferably powdered, is introduced into a tank 1, the solvent mixture run in from a tank 7 through a pipe 8, and heat is applied by means of a steam jacket 2 while stirring mechanism 5 is operated. When extraction is completed and the stirrer stopped, the clear solution is led off by pipes 17 through a cooler 18 to a tank 19 where the solution is agitated with a dilute alkali such as ammonia introduced through a pipe 26 from a tank 27. The alkali-treated solution flows through pipes 30 to a vessel 31 where it is treated with water introduced through a pipe 36 and perforated plate 35 while stirring. The washed solution is passed through a filter 43 to a still 44 where the solvent is distilled off. The molten, purified resin is blown with air in the still to raise the melting point. The sludge left in tank 1 is passed through a steam-jacketted pipe 15 to a still 16, to which also is led the precipitate produced in the alkali treatment tank 19, and, if desired, the washings from the vessel 31. Solvent distilled off in still 44 is condensed in condenser 12 and returned to tank 7 through pipe 13. The solvent distilled off in still 16, evaporated in tank 1, or driven fff from tank 19 when empty by the admission of steam at 23, is condensed in condenser 11 and returned to tank 7 by way of a water separator 10. The alkali-treatment tank 19, and washing vessel 31 may be <PICT:0414716/III/1> replaced by a single vessel into which first alkali, then water, are admitted through a distributing spray; a reflux condenser may be introduced into the vapour pipe 52 from still 16 having an outlet leading to the alkali tank 27 for the purpose of recovering ammonia before the solvent vapours are condensed in condenser 11; in the treatment of crude resin from hill timber, the treatment with alkali may be omitted, the washing with water may take place in the extraction vessel 1 instead of in a separate tank, and two or more extraction vessels may be employed to obtain continuous operation of the plant. The apparatus, or parts thereof, are made of stainless steel, aluminium, or other material unaffected by the resin. The Specification as open to inspection under Sect. 91 describes also the use of benzol alone as the treating liquid. This subject-matter does not appear in the Specification as accepted.