Abstract: Processes are described for obtaining highly purified tetrahydrocannabinolic acid (THCa) from Cannabis. Solvent extraction is performed on plant material or extract, followed by removal of impurities using sequential liquid-liquid extractions to purify cannabinoid carboxylic acids therefrom based on chemical properties of carboxylate salts. The product liquor, comprising THCa in solvent, is largely free of impurities, and high in THCa. Further steps can be conducted to obtain a highly enriched solution using chromatography and subsequent crystallization of THCa in 99% purity. THCa can be used as starting material for other products that include THC by decarboxylation. Optionally, triglyceride extraction of a washed aqueous phase can be used to prepare a THCa composition without chromatographic purification. A pre-processing aqueous extraction with pH manipulations may be used to remove biomass prior to solvent extraction, while maintaining THCa and optionally other cannabinoid acids.

Abstract: A chair back is supported on a rigid upright coupled to a horizontal tilt shaft disposed under the front of the chair seat and supported on a control housing fixed to a pedestal. A tension mechanism urges the upright into an upright position. The chair seat is movably supported on the upright by an arrangement which permits the seat to pivot about a transverse horizontal axis positioned adjacent the upper surface of the seat. A control link is pivoted at one end to the control housing, and the other end has lost-motion pivotal connections to the seat frame and the upright. The lost-motion pivotal connection to the seat frame including a spring cooperating between the upright and the seat frame to allow the seat to move relative to the upright.