Schweizer’s reagent

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... 

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... 

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. 

Cellulose derivatives may be detected by running the tests outlined under Section 6.2.16. Vulcanized fiber (also called hydrocellulose) dissolves in Schweizer s reagent (also known as cuoxam solution). However, the latter is somewhat difficult to produce, so it is often inappropriate for indicative tests. 

Physkalproperties C. is relatively hygroscopic, it absorbs 8-14% of water. C. is insoluble in water or dilute acids in alkaline solutions it swells strongly and the short-chain units with DP<200 (a-C.) dissolve. C. dissolves in zinc chloride solution or copper salt solutions containing ammonia (Schweizer s reagent, Cuoxam) or ethylenediamine (Cuen) C. does not melt, flame point > 290 °C. C. is colored blue-violet by chlo-... 

Chief constituent of the cellular tissue or fibre of plants. Cotton is the purest natural form and contains about 90%. Flax, hemp, ramie, etc., are less pure forms. Present in wood and straw (30-40%). The action of 17-18% NaOH dis-tinguishes three celluloses, viz. a c ulose (insol), cellulose (sol. and re-pptd. by acids), and y>cellulose (permanently sol.). a-Cellulose is that normally referred to as pure cellulose. It is insol. in all ord. org. solvents, but dissolves in cold 70% HgS04 (re-pptd on dilution— hydrocellulose), cone. ZnGg-Aq., ammoniacal copper hydroxide sol. (Schweizer s reagent), and in NaOH + CS2 (forms sodium xanthogenate). Does not react with phenylhydrazine or hydr-oxylamine. TaJres up one mol. NaOH for each CgHipOs unit, the NaOH being recovered by... 

Schweizer s reagent reactivo de Schweizer scientist cientifico scillaren escilareno scillarenin escilarenina scilliroside escilirosida scintillation centelleo... 

Chitin is a white, amorphous solid, insoluble in water, dilute acids, dilute and concentrated alkali, and organic solvents. It readily dissolves in concentrated hydrochloric, sulfuric, nitric, and phosphoric acids, in anhydrous formic acid, with difficulty in liquid ammonia, but not in Schweizer s reagent. Hot, concentrated solutions of neutral salts, like lithium and calcium thiocyanate, dissolve chitin, which can then be reprecipitated by dilution with alcohol or acetone, without apparent degradation. 

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