Extraction regeneration

In contrast to dead-end microfiltration, which could also be used to remove solids from spent electrolytes producing (after addition of a solvent and at elevated temperatures) an ionic liquid as residue, the residue in the extractive regeneration is wet sludge only. 

Two separation and recovery circuits for two different products. Each consists of crystallization, intermediate product leaching, final product recovery and extractant regeneration (C,I,P,R). 

The circular process of extraction, regeneration and recompression for the different extraction gases is shown in Figure 1 and Figure 2. 

Phillips was the first to practise extractive distillation on the industrial scale around 1940, using furfural as the solvent A number of improvements were made in the 1960s, The process has a single extraction regeneration step and a purification step. 

The BASF Lurgi process, industrialized since 1968 and employing NHnethylpyiTOlidQiie as solvent, is also One of the most widespread technologies today. It is similar in principle to the other techniques, but is difierent in its practical implementation, as shown by Fig. 3X The process takes place as If the first extraction/regeneration stq> was actually divided into three parts ... 

Figure 14-7. Batch SCF extraction regeneration is by pressure swing...

Lewis and Yang (1992) studied the process of propionate production from lactose by P. acidipropionici ATCC 4875 immobilized on surgical cotton fiber placed in the bioreactor. The productivity was increased by almost 100% by the continuous selective extraction of propionic acid with a tertiary amine solution (40% alamine in 2-octanol). Propionic acid was isolated and the extractant regenerated by adding small amounts of IN NaOH solution, A concentrated propionate salt was obtained as the final product. 

Amino-4 -methylthiazole slowly decomposes on storage to a red viscous mass. It can be stored as the nitrate, which is readily deposited as pink crystals when dilute nitric acid is added to a cold ethanolic solution of the thiazole. The nitrate can be recrystallised from ethanol, although a faint pink colour persists. Alternatively, water can be added dropwise to a boiling suspension of the nitrate in acetone until the solution is just clear charcoal is now added and the solution, when boiled for a short time, filtered and cooled, deposits the colourless crystalline nitrate, m.p. 192-194° (immersed at 185°). The thiazole can be regenerated by decomposing the nitrate with aqueous sodium hydroxide, and extracting the free base with ether as before. 

The ease with which amines are extracted into aqueous acid combined with their regeneration on treatment with base makes it a simple matter to separate amines from other plant materials and ni trogen containing natural products were among the earliest organic compounds to be studied Their basic... 

Isolate. A relatively pure chemical produced from natural raw materials by physical means, eg, distillation, extraction, crystallization, etc, and therefore natural or by chemical means, ie, via hydrolysis, bisulfite addition products, and regeneration, etc, and therefore artificial by 1993 U.S. labeling regulations. 

Polymers. Hydrocarbons from petroleum and natural gas serve as the raw material for virtually all polymeric materials commonly found in commerce, with the notable exception of rayon which is derived from cellulose extracted from wood pulp. Even with rayon, however, the cellulose is treated with acetic acid (qv), much of which is manufactured from ethylene (see Fibers, regenerated cellulosics). 

The chemical yield of hydrogen peroxide and the anthraquinone per process cycle is very high, but other secondary reactions necessitate regeneration of the working solution and hydrogenation catalyst, and the removal of organic material from the extracted hydrogen peroxide. 

Raffinate acid from the first cycle, containing approximately 7 to 14 g/L U Og is then reoxidized and re-extracted in the second, purification cycle using a solvent containing 0.3 Af D2EHPA and 0.075 AfTOPO. The loaded solvent is washed with iron-free acid to remove iron and then with water to remove extracted and entrained acid. The solvent is stripped with ammonium carbonate [506-87-6] to yield ammonium uranyl tricarbonate [18077-77-5] which is subsequendy calcined to U Og (yellow cake). The stripped solvent is regenerated with mineral acid before recycling (39). 

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