Abstract: Method for synthesizing L-2-oxothiazolidine-4-carboxylate and its acid, L-2-oxothiazolidine-4-carboxylic acid. The present invention involves the separation of phenol from a reaction mixture containing L-2-oxothiazolidine-4-carboxylate and phenol. In the present method a reaction mixture containing phenol, L-2-oxothiazolidine-4-carboxylate, and chloride salt, is contacted with a phenol adsorbing adsorption resin, the adsorption resin comprising a polymer having a polyethylene backbone. The adsorption resin is capable of adsorbing substantially all of the phenol while not adsorbing substantial amounts of the L-2-oxothiazolidine-4-carboxylate from the reaction mixture.

Abstract: An apparatus for continuous fluid-solid contacting includes a plurality of chambers on a rotating carousel, each chamber having a supply conduit and a discharge conduit, and a single valve for controlling a supply and discharge of fluid to the chambers. The valve includes a stationary annular disk having a plurality of conduits and a lower planar surface forming a disk valve face, and a rotatable annular plate having an upper planar surface forming a plate valve face and a plurality of holes forming ports in the plate valve face. The plate is supported in pressurized contact with the disk valve. The frame supporting the chambers and the annular plate are rotated by separate devices. To ensure that the valve ports remain in rotational correspondence with the rotating chamber frame, the invention includes optical control for synchronizing the rotation of the frame and the rotation of the annular plate.

Abstract: A process for removal of vanadium from wet process phosphoric acid comprising the steps of;(i) adsorbing an anionic pentavalent complex of vanadium, derived from the wet process phosphoric acid, onto an anion exchange resin or into an organic layer; and(ii) reducing the vanadium complex to trivalent and/or tetravalent vanadium so as to selectively strip vanadium from the anion exchange resin or from the organic layer.

Abstract: A process for producing hydrofluoric acid from SiF.sub.6.sup.2- in a wastewater is disclosed. The process is carried out by(i) combining (NH.sub.4).sub.2 SO.sub.4, at a pH high enough such that the sulfate is in its divalent state, with SiF.sub.6.sup.2- from said wastewater in an amount in excess of that stoichiometrically required to form (NH.sub.4).sub.2 SiF.sub.6 as follows:(NH.sub.4).sub.2 SO.sub.4 +SiF.sub.6.sup.2- .fwdarw.(NH.sub.4).sub.2 SiF.sub.6 +SO.sub.4.sup.2-(ii) concentrating a solution including (NH.sub.4).sub.2 SiF.sub.6 and excess (NH.sub.4).sub.2 SO.sub.4 to precipitate and separate (NH.sub.4).sub.2 SiF.sub.6 of high purity therefrom;(iii) re-solubilizing the (NH.sub.4).sub.2 SiF.sub.6 for reaction with NH.sub.4 OH to form NH.sub.4 F liquor and precipitated Si(OH).sub.4 ;(iv) separating the NH.sub.4 F liquor from the precipitated Si(OH).sub.4 ;(v) reacting the NH.sub.4 F with water to form precipitated NH.sub.4 F.multidot.HF and ammonia gas;(vi) reacting NH.sub.4 F.multidot.