Water-removing purifiers

Not aU purifiers on the market are adequate for use in carrier-gas lines and for this reason columns often fatigue before a color change is visible. Purifiers constructed from plastic tubing tend to allow water and oxygen to permeate into the gas line (18). Most water-removing purifiers using Drierite and similar color indicators do not completely remove water. Also avoid purifiers that have O-ring... 

Water formed in the reaction as well as some undesirable by-products must be removed from the acetic acid solvent. Therefore, mother Hquor from the filter is purified in a residue still to remove heavies, and in a dehydration tower to remove water. The purified acetic acid from the bottom of the dehydration tower is recycled to the reactor. The water overhead is sent to waste treatment, and the residue still bottoms can be processed for catalyst recovery. Alternatively, some mother Hquor from the filter can be recycled directiy to the reactor. 

The by-product ammonia is vented from the reactor during the course of the reaction. Unconverted aniline is distilled off at the end of the reaction and the diphenylamine is washed with aqueous hydrochloric acid to remove trace amounts of aniline. The product is then washed with water and purified in a refining stiU. 

Chevron s WWT (wastewater treatment) process treats refinery sour water for reuse, producing ammonia and hydrogen sulfide [7783-06-04] as by-products (100). Degassed sour water is fed to the first of two strippers. Here hydrogen sulfide is stripped overhead while water and ammonia flow out the column bottoms. The bottoms from the first stripper is fed to the second stripper which produces ammonia as the overhead product. The gaseous ammonia is next treated for hydrogen sulfide and water removal, compressed, and further purified. Ammonia recovery options include anhydrous Hquid ammonia, aqueous Hquid ammonia, and ammonia vapor for incineration. There are more than 20 reported units in operation, the aimual production of ammonia from this process is about 200,000 t. 

The excess diethyleneglycol is removed in vacuo and the residue dissolved in water and then in benzene. The benzene extract is washed several times in water, then purified in vacuo. The 1-p-chlorobenzhydryl-4-<2 -[2"- 2" -hydroxyethoxy)-ethoxy] -ethyDpiperazine obtained distills at 250°C/0.01 mm Hg. 

Remove excess reactant by extensive dialysis against water. The purified polyaldehyde dextran may be lyophilized for long-term storage. 

Benzyl Azidodithiocarbonate, QH CHa SCSNs, mw 209.30, N 20.08% col monoclinic prisms, mp 66 very sol in acet, EtOAc, CSa or CHC1S si sol in ale or MeOH and moderately sol in eth or benz. It was prepd by the interaction of benzyl chloride andNa azidodithiocarbonate in acet at RT. The ppt NaCl was removed by filtration and the crude prod which separated on addn of water was purified by re-crystn from chlf... 

The aldehyde or ketone (30 50 mL) was dissolved in benzene or toluene (30 50 mL) in a 100-150-mL round-bottomed flask equipped with a reflux condenser, a Dean Stark trap, and a magnetic stirring bar. Benzylamine (1 equiv) and TsOH - H20 (1 mol %) were added and the mixture was stirred at reflux. When the reaction was complete (theoretical amount of water removed monitored by GC, TLC. H and l FNMR), the solvent was removed under reduced pressure and the imine product 14 was purified by column chromatography. 

N-Methanesulfonyl-9-oxo-lla,15a-dihydroxy-5-cis-13-trans-16-phenoxy-(n-tetranorprostadienamide To 1.0 mmols of 9-oxo-lla,15a-bis-(tetrahydropyran-2-yloxy)-16-phenoxy-cis-5-trans-13-(n-tetranorprostadienoic acid in 40 ml THF is added 2 ml triethylamine. After 15 minutes of stirring at room temperature 10.0 ml of 0.1 M methanesulfonylisocyanate in THF is added. After a further 1 hour of stirring, the reaction mixture is neutralized with acetic acid and the solvent removed by evaporation (in vacuo). The resultant residue is taken up in methylene chlorine and washed successively with water and sodium bicarbonate to yield, after drying and solvent evaporation, N-methanesulfonyl-9-oxo-lla,15a-bis-(tetrahydropyran-2-yloxy)-16-phenoxy-cis-5-trans-13-co-tetranorprostadienamide. This intermediate is then hydrolyzed overnight with acetic acid/water and purified by column chromatography to give the desired N-methanesulfonyl-9-oxo-lla,15a-dihydroxy-5-cis-13-trans-16-phenoxy-co-tetranorprostadienamide. 

Styrene (99% pure) was obtained from Fisher Scientific and Aldrich Chemicd. It was used either as supplied or after purification to remove the inhibitor. To remove the inhibitor, styrene (Aldrich) was washed three time with 10% sodium hydroxide and dried over phosphorus pentoxide in a desiccator after repeated washing with water. The purified sample was stored under nitrogen at 0<>C. Potassium persulfate and AIBN initiators were obtained from Fisher and DuPont, respectively, and were used without further purification. Sodium... 

To purify the potassium nitrate re-desolve the dry crystals in the smallest possible amount of boiled water. Remove any salt crystals that appear (Step 7) pour through an improvised filter made of several pieces of paper and evaporate or gently heat the concentrated solution to dryness. 

Water is a remarkable compound possessing a unique set of physical and chemical properties. Water is purified in domestic water supplies in a multi-step procedure that includes aeration, addition of slaked lime, removal of particles by coagulation and flocculation, addition of CO2, filtration, reduction of pH, and addition of chlorine disinfectant to kill bacteria. High-purity water is obtained by distillation. 

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