Schweizer reagent

Protecting groups were removed by treatment of the polymer with sodium methoxide in p-dioxane, followed by tetraethylammonium hydroxide. Although nitrogen-free polymers were obtained by this procedure, the polymers had suffered a 16-20% decrease in PH. The resulting polymers were insoluble in water, sodium hydroxide, N, -dimethylformamide, and methyl sulfoxide, but were soluble in tetraethylammonium hydroxide and in Schweizer reagent. 

Cellulose was reported as a wall constituent of the conidiophores of Aspergillus niger, based on the physical appearance of the fibrils. However, walls of Aspergillus niger and Aspergillus clavatus were shown to be insoluble in Schweizer reagent and to contain chitin. The cell walls of Haplosporangium parvum were reported to contain... 

In 1937, Schweizer [91] discovered that cellulosic fibers such as cotton and hemp readily dissolve in copper hydroxide and ammonium hydroxide solutions. His system is recognized as the Schweizer reagent. The Bemberg Rayon Industry later utilized this solvent for the industrial production of cuprammonium fibers (or cuprammonium rayon) and developed the Bemberg process or cuprammonium process [92]. Kamide and Nishiyama [93] have recently published an excellent review on the history and science of cuprammonium technology. 

Schweizer s reagent The dark blue solution obtained by dissolving Cu(OH)2 in concentrated ammonia solution. Used as a solvent for cellulose, the cellulose is precipitated on acidification. Used in the cuprammonium process for the manufacture of rayon. 

Cuprammonium A process for making regenerated cellulose fibers. Cellulose, from cotton or wood, is dissolved in ammoniacal copper sulfate solution (Schweizer s reagent, also called cuprammonium sulfate). Injection of this solution into a bath of dilute sulfuric acid... 

Most linear ceilulosics may be dissolved in solvents capable of breaking the strong hydrogen bonds. These solvents include aqueous solutions of inorganic acids, zinc chloride, lithium chloride, dimethyl dibenzyl ammonium hydroxide, and cadmium or copper ammonia hydroxide (Schweizer s reagent). Cellulose is also soluble in hydrazine, dimethyl sulfoxide in the presence of formaldehyde, and dimethylformamide in the presence of lithium chloride. The product precipitated by the addition of nonsolvents to these solutions is highly amorphous and is called regenerated cellulose. 

Allied to the cuprammmes is Schweizer s reagent, which is prepared by dissolving cupric hydroxide in an aqueous solution of ammonia, when a deep blue liquid is obtained which has the property of dissolving... 

Edward E. Schweizer, Encyclopedia of Reagents for Organic Synthesis, John Wiley and Sons,... 

Salicylate annelation, 279-280 Salutaridines, 593 Samarium(ll) iodide, 464-465 Sarkomycin, 457, 458 Schweizer s reagent, 597 Selenium, 465-466 Selenones, 123 Selenuranes, 223 Shapiro reaction, 563-565 Sharpless epoxidation, 263, 600 Shikimic acid, 3, 4, 548 Sibirinone, 596 Sila-Pummerer reaction, 576 Silica, 466... 

Ey-AllylaminesThe reaction of Schweizer s reagent with sodiophthalimide and an aldehyde in the presence of LiBr as a Lewis acid mediator gives allylic phthalimides in an (E)/(Z) ratio of 2-3 1. Surprisingly, use of vinyltri-n-butylphos-phonium bromide in this same reaction results in the (E)-allylic phthalimide (75— 100% yield). 

Cellulose, regenerated SCHWEIZER s reagent Organic solvents... 

Among the best-known nonderivatizing solvent systems is a combination between copper, alkali, and ammonia termed Schweizer s reagent. Solutions of cuprammonium hydroxide have been used for both analytical and industrial cellulose dissolution. Regenerated fibers with silk-like appearance and dialysis membrane have been (and partially continue to be) industrial products on the basis of cellulose dissolution in cuprammonium hydroxide. The success of this solvent is based on the ability of copper and ammonia to complex with the glycol functionality of cellulose as shown inO Fig. 11. Because of the potential side reactions (oxidation and crosslinking, Norman compound formation), alternatives to both ammonia as well as copper have been developed. Cuen and cadoxen are related formulations based on the use of ethylene diamine and cadmium, respectively. The various combinations of alkali, ammonia. 

The third type of cellulose regenerate with commercial significance operates on the basis of cuprammonium hydroxide (Schweizer s reagent). The process had significance for fibers in the first half of the 20th century, but it started to decline in the 1960s due to insurmountable obstacles in the recovery of copper ions. The main producer of cuprammonium fibers... 

Reaction of vinyl Wittig reagents with carbonyl-substituted pyrroles has been used to generate the pyrrolizine ring system, from which pyrrolizidines are available by reduction. In this way, Schweizer and Light prepared... 

Schweizer and Liehr7 showed that the reagent reacts with the sodium salt of an a-hydroxy ketone to give a 2,5-dihydrofurane (3), for example the 3-phenyl derivative. 

Schweizer and Thompson8 prepared 2H-l-benzopyrane by reaction of the sodium salt of salicylaldehyde with the reagent in DMF to give 2-H-l-benzopyrane (4). 

Heterocycles. Schweizer et al. have reported the synthesis of several heterocyclic systems using this reagent, which undergoes addition with primary amines to give jJ-aminopropenyltriphenylphosphonium bromides. On treatment with bases these products form heterocychc systems with extrusion of triphenyl-phosphine oxide or methylenetriphenylphosphorane. 

A considerable amount of work has been devoted to the action of ionizing radiation on polymeric carbohydrates in the solid state, in particular with regard to its effect on the mechanical properties even though some chemical effects have also emerged. For a recent review see [99]. Of these polymers, cellulose has been the most studied (c/. [99, 100]). Native cellulose is locally crystalline. Determination of chain breakage by radiolysis has usually been done after dissolution through complexation, e.g. as the copper-ammine complex (Schweizer s reagent), or the cadmium-ethylenediamine complex. 

Formula weight 165.68. Schweizer s reagent dissolves cellulose. 

Edward E. Schweizer, Encyclopedia of Reagents for Organic Synthesis, John Wiley and Sons, Inc. New York, edited by L.A. Paquette. 1995,7, 5508 ... 

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