Extraction-reduction

Solvent extraction reduction is most frequently performed mainly in connection with the extraction of solid and biological samples by liquid partition. Extractions are typically accomplished using a Soxhlet apparatus that provides the benefits of multiple extractions. By repeated distillation and condensation of the solvent, the apparatus allows multiple extractions using the same (small) volume of solvent. Soxhlet extraction has been a standard method for many decades, and it is often the method against which other extraction methods are measured and verified [14]. 

Malathion, dimethoate, omethoate, chlorfenvin-phos Vegetables (lettuce, tomatoes, cabbage) Dichloromethane extraction Reductive amperometric detection. GC with alkali flame ionisation and photometric detection < 0.1 mg/kg [103]... 

It is well known that silver (I) can be reduced to the metallic state with various organic substances and thus agitation of silver (I) with some extractants may reduce it. In the literature, the solvent extraction-reduction process possesses metallic ions were extracted form an aqueous solution to organic solvents and then the ions were reduced in the organic phase by reductant or radiation. In this work, we report a new strategy to prepare wicker-shaped silver. The primary amine N1923 is used as extractant and reductant. 

In summary, the wicker-shape silver is prepared by extraction-reduction. In the process of the preparation, the primary amine N1923 act as the reductant, extractant and template and the conditions of the extractants are also important. 

Extraction of organic pollutants from solid or semi-solid matrices has been widely investigated in recent years. New instrumental approaches have led to developments in terms of speed of extraction, reduction in organic solvent consumption and the introduction of automation. However, these instrumental approaches... 

Various approaches were developed to prepare silver nanoparticles with the size less than 100 nm photolytic [7] and radiolytic reduction [8], the sonochemical method [9], solvent extraction reduction [10]. Among these methods, chemical reduction is the most common one. One could control the intrinsic properties of synthesized silver nanoparticles during chemical synthesis [11] by reducing the concentration of silver salts and using larger amount of stabilizer to avoid aggregation of the nanoparticles. 

Two further examples of type I ternary systems are shown in Figure 19 which presents calculated and observed selectivities. For successful extraction, selectivity is often a more important index than the distribution coefficient. Calculations are shown for the case where binary data alone are used and where binary data are used together with a single ternary tie line. It is evident that calculated selectivities are substantially improved by including limited ternary tie-line data in data reduction. 

Pu (86 years) is formed from Np. Pu is separated by selective oxidation and solvent extraction. The metal is formed by reduction of PuF with calcium there are six crystal forms. Pu is used in nuclear weapons and reactors Pu is used as a nuclear power source (e.g. in space exploration). The ionizing radiation of plutonium can be a health hazard if the material is inhaled. 

C, b.p. 907"C, d 713. Transition element occurring as zinc blende, sphalerite (Zn,Fe)S calamine or smithsonite (ZnCO j), willemite (Zo2Si04), franklinite (ZnFe204). Extracted by roasting to ZnO and reduction with carbon. The metal is bluish-white (deformed hep) fairly hard and brittle. Burns... 

Reference to Figure 3.4 shows that the reduction is not feasible at 800 K. but is feasible at 1300 K. However, we must remember that energetic feasibility does not necessarily mean a reaction will go kinetic stability must also be considered. Several metals are indeed extracted by reduction with carbon, but in some cases the reduction is brought about by carbon monoxide formed when air, or air-oxygen mixtures, are blown into the furnace. Carbon monoxide is the most effective reducing agent below about 980 K, and carbon is most effective above this temperature. 

Each of these elements can be extracted by reduction of the respective oxide at high temperature, using either carbon or hydrogen or by electrolysis of an aqueous solution of a salt of the required element. 

Reduction by aluminium has been used to produce molten iron in situ for welding steel and as a method of extracting metals. 

The extraction of titanium is still relatively costly first the dioxide Ti02 is converted to the tetrachloride TiCl4 by heating with carbon in a stream of chlorine the tetrachloride is a volatile liquid which can be rendered pure by fractional distillation. The next stage is costly the reduction of the tetrachloride to the metal, with magnesium. must be carried out in a molybdenum-coated iron crucible in an atmospheric of argon at about 1100 K ... 

The process of extraction requires first smelting (to obtain the crude metal) and then refining. In smelting, iron ore (usually an oxide) is mixed with coke and limestone and heated, and hot air (often enriched with oxygen) is blown in from beneath (in a blast furnace). At the lower, hotter part of the furnace, carbon monoxide is produced and this is the essential reducing agent. The reduction reactions occurring may be represented for simplicity as ... 

Reduction adapters. These may be employed to connect condensers, still-heads, etc. to flasks, extraction apparatus and the like. Numerous combinations (Fig. II, 56, 2) are, of course, possible, but the commonest sizes are socket 514 to cone 519 or 524 socket 519 to cone 524, 529... 

Methylene chloride CHjCl, b.p. 41°, is obtained as a by product in the com mercial preparation of chloroform by the reduction of carbon tetrachloride with moist iron and also as one of the products in the chlorination of methane it is a useful extraction solvent completely immiscible with water. 

The reduction takes place at a comparatively low temperature and is fairiy rapid for acetophenone. With higher ketones, the upper layer of the initial distillate should be returned to the contents of the flask and the refluxing continued for 3-6 hours. The reaction mixture and aqueous distillate are then combined, extracted with ether, etc. 

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