The invention provides a process for the separation of MEG and 1,2-BDO from a first mixture comprising MEG and 1,2-BDO in a first solvent by the steps of: (i) combining said first mixture with a second solvent stream comprising a second solvent in a first extraction column; (ii) recovering (a) a second mixture of MEG and 1,2-BDO in the second solvent, wherein the molar ratio of MEG:1,2-BDO is lower in the second mixture than in the first mixture; and (b) a solution comprising MEG in the first solvent; (iii) combining said second mixture with a first washing stream, said first washing stream also comprising the first solvent in a second extraction column; (iv) recovering (c) a first extract stream comprising the second solvent and 1,2-BDO and (d) a third mixture comprising MEG and, optionally, 1,2-BDO in the first solvent.

A process of solvent extraction for separation of rare earth elements (REEs) based on separation factor is provided. The method includes repeatedly contacting the REEs containing aqueous solution with a suitable solvent containing a diluent and/or a modifier and an REE as a partial reflux.

The present invention provides a process for the production of an aromatic dicarboxylic acid comprising the catalytic oxidation of a hydrocarbon precursor in an organic solvent, comprising the steps of: i) separating a vent gas from an oxidation stage into an organic solvent-rich liquid stream and a water-rich vapor stream in a distillation stage; and ii) separating an aqueous purification mother liquor comprising organic compounds from purified aromatic dicarboxylic acid crystals in a separation stage, characterized in that the process further comprises the steps of: iii) transferring the aqueous purification mother liquor from the separation stage to an extraction stage; iv) extracting said organic compounds from the aqueous purification mother liquor by contacting the aqueous purification mother liquor at a temperature of at least 90? C. with an organic liquid in the extraction stage to form an aqueous phase and an organic phase, wherein the concentration of said organic compounds in the aqueous phase is lower than the concentration of said organic compounds in the aqueous purification mother liquor; and v) transferring the aqueous phase to said distillation stage. The present invention further provides an apparatus for carrying out the process.

The invention describes processes to selectively remove or reduce the mineral acid content substantially from compositions comprising a solvent and levulinic acid, wherein the levulinic acid was derived from the reaction between various biomass materials and a mineral acid or an organic acid catalyst.

The present invention provides a process for preparing a high-purity nickel sulphate solution, comprising the steps of: i. providing an aqueous feed solution comprising nickel. cobalt, calcium and magnesium: ii. extracting cobalt, calcium, and partly magnesium from said aqueous feed solution using a first solvent comprising a first alkylphosphorus-based acidic extractant, thereby obtaining an aqueous raffinate comprising nickel and magnesium: iii. extracting magnesium from said aqueous raffinate solution comprising nickel and magnesium using a second solvent comprising a second alkylphosphorus-based acidic extractant, thereby obtaining a high-purity aqueous nickel sulphate solution comprising nickel and magnesium: iv. stripping the first loaded solvent comprising cobalt, calcium and magnesium with an aqueous solution comprising a mineral acid.

A liquid-liquid extraction system includes extraction stages, a pumping system, and a controller. Each extraction stage has a chamber, a primary input, a raffinate output, and an extract output. An input liquid (e.g., either a source liquid or raffinate from a preceding extraction stage, mixed with an extraction liquid) is presented to the chamber via the primary input. The chamber enables phase separation of liquid therein, into a raffinate and a extract, where the raffinate exits the separation vessel at the raffinate output, and the extract exits the separation vessel at the extract output. A level sensor is coupled to the chamber and the controller is operatively programmed to read an output of the level sensor, compare the output of the level sensor to a target, and cause the associated chamber to receive additional liquid if the output is lower than the target.

Methods and apparatus for the purification of isoprene, such as the purification of a bioisoprene composition from fermentor off-gas. The apparatus includes two columns that process the fermentor off-gas, which includes isoprene and various impurities. A solvent is added to the off-gas in the first column, and the isoprene is stripped from the solvent in the second column. Also provided is a downstream further purification process. Also provided are the resulting purified isoprene compositions.

Methods and apparatus for the purification of isoprene, such as the purification of a bioisoprene composition from fermentor off-gas. The apparatus includes two columns that process the fermentor off-gas, which includes isoprene and various impurities. A solvent is added to the off-gas in the first column, and the isoprene is stripped from the solvent in the second column. Also provided is a downstream further purification process. Also provided are the resulting purified isoprene compositions.

Disclosed herein are methods for recovering diphosphonite-containing compounds from mixtures comprising organic mononitriles and organic dinitriles, using multistage countercurrent liquid-liquid extraction. Recovery is enhanced with one or more method steps. In a first step, a portion of the heavy phase from the settling section of the first stage is recycled to the settling section of the first stage. In a second step, a portion of the light phase from the settling section of the first stage is recycled to the mixing section of the first stage. In a third step, the first stage takes place in a mixer-settler, a Lewis base is introduced into the settling section of the first stage, and a complex of Lewis acid and Lewis base is formed in this settling section. In a fourth step, a polyamine is added to the first stage.

Liquid-liquid extraction column (1) comprising injection points for feedstock (2), for washing (3) and for backwashing (4), two withdrawal points (5, 6), trays (P.sub.i) located along the column and defining 2 to 30 zones each comprising at least two trays, the n zones comprising: at least one extraction zone Z.sub.i comprising the zones from Z.sub.1 to Z.sub.x, x being greater than or equal to 1, and at least one backwash zone comprising the zones from Z.sub.x+1 to Z.sub.n, n being greater than x; in which the trays of one and the same zone exhibit one and the same height H of inter-tray space (10); in which, when x>1, the height H of the zones Z.sub.i increases when i increases; and, when x=1, the height H of the at least one backwash zone is less than the height H of zone Z.sub.1.