Green products isolation

Direct chlorination of powdered technetium metal gives a blue product, not TcClg by reducing the amount of oxygen contamination the amount of blue material produced can be reduced but not eliminated. Chlorination of the metal on porous pot affords a green product which resembles TcCl . Both the blue and green products are, in fact, mixtures of purple TcOCl. and colourless TCOCI3 and these compounds have been isolated pure by vacuum distilla-... 

Thienothiophenes undergo the indophenine reaction with isatin (see Section III,I). Oster reported that thieno[2,3-6]thiophene (1) gave a green product with a ratio of isatin to thienothiophene 1 1, and a blue substance with the ratio of the initial substances 2 1. Steinkopf and HempeP could not obtain this blue substance instead they isolated a brown material with the isatin to thienothiophene 1 ratio 2 3 at +50° they isolated a substance with the ratio 1 1 and at +70°, with ratio 1 2. Steinkopf and PetersdorP found that a reaction of 2-acetylthieno[2,3-6]thiophene with isatin produces 2- or 3-(2-thieno[2,3-6]thienyl) cinchoninic acid. The acid was decarboxylated to 2- or 3 2-thieno[2,3-6]thienyl)quinoline (the site of quinoline group in thienothiophene 1 molecule was not established). 

The entire Step 1 product was dissolved in 21.21 methyl alcohol saturated with ammonia, then treated with Raney nickel catalyst (200 g), and hydrogenated at 50°C for 40 hours under 4 bar hydrogen. The catalyst was then removed by filtration, the mixture concentrated, and the product isolated in 93.7% yield as green oil. 

A solution of the Step 5 product (0.60 mmol) dissolved in 8 ml THF was placed into a 203 mm x 38 mm pressure tube containing a small stirring bar, then cooled to -78°C, and treated with 8 ml NH3 and sealed. The mixture was stirred 10 minutes at -78°C and 48 hours at ambient temperature. Excess NH3 was released, the mixture concentrated, and the product isolated in 99% as an yellowish-green solid. 

A suspension of the Step 1 product (0.18 mol) in 250 ml water was treated with a single portion of solid potassium iodide (0.33 mol) and 50 ml acetic acid, then stirred 1 hour at ambient temperature. Gaseous sulfur dioxide was bubbled through the mixture until a pale green suspension was formed. The solid was isolated, co-evaporated three times with 250 ml toluene, dried, and the product isolated in 64% yield. 

To a stirred solution of naphthalene (0.045 mol) dissolved in 50 ml dimethoxyethane was added sodium metal (0.039 mol) and the mixture stirred 4 hours until a dark green color persisted. The product from Step 2 (0.016 mol) dissolved in 20 ml dimethoxymethane was added, the reaction stirred 2 hours, and then quenched with saturated 70 ml brine. The mixture was partitioned between 250 ml apiece EtOAc and 10% HCl, the organic layer discarded, and 10% NaOH added to the aqueous layer until pH 7 obtained. The aqueous layer was extracted twice with 100 ml CH2CI2, dried, filtered, concentrated at 25 °C at 150 torr, and the product isolated in 86% yield. and C-NMR, IR, MS and elemental analysis data supplied. 

Potentially, supercritical carbon dioxide (SCCO2) is the ideal green solvent. It is non-toxic for both humans and the environment. It is chemically inert under most conditions, whether they be non-flammable or non-protic, and it is inert to radical and oxidizing conditions. This gas can be obtained in large quantities as a by-product of fermentation, combustion, and ammonia synthesis and it is relatively cheap, particularly compared with conventional solvents. Supercritical carbon dioxide presents other practical advantages as well, such as the possibility of achieving product isolation to total dryness by simple evaporation. 

EXPERIMENT 3.1 SYNTHESIS OF A/,A/ -DISALICYLALDEHYDE-1,3-PROPANEDIIMINENICKEL(ll), [Ni(salpd)] AND ISOLATION OF THE BROWN AND GREEN PRODUCTS... 

This chapter is concerned with green reactions, products and methodological advances facilitating them. To those ends, our work has attempted to simplify processes by combining as many tasks as possible into unit operations. Aspects include selection of media, reactants, catalysts, conditions and product isolation. Examples are presented along with details of some specific classes of relatively complex molecules that may be prepared. These include novel macro-cycles, ligands and phenol/formaldehyde oligomers. 

Ionic liquids used as the green solvents could avoid the utilization of volatile hazardous organic solvents, simplify the product isolation in the homogeneous catalytic reaction systems, and provide the access to the recovery and reuse of the catalytic systems as well besides, it can avoid the pollution. Furthermore, the ionic liquids could act as the catalysts, ligands, or supports of reagents through the functionalization of the ionic liquids. 

The simple experimental and product isolation procedures combined with ease of recovery and reuse of this novel reaction media contribute to the development of green strategy for the preparation of isoxazolidines. Furthermore, the use of [bmim] [PFg] solvent system for this transformation avoids the use of toxic or corrosive reagents and high temperature reaction conditions, and thus, it provides convenient procedure to carry out the reactions at ambient temperature. 

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