Cuprammonium reactions

In another oudine, cellulose was complexed with cuprammonium ions (Nicoll and Conaway, 1943). Lately, laboratory-scale isolation has relied on polar aprotic solvents and solvent systems, e.g., dimethylsulfoxide, pyridine, Af,7V-dimethylacetamide-lithium chloride, and l-methyl-2-pyrrolidinone-lithium chloride (Baker et al., 1978 McCormick and Shen, 1982 Seymour et al., 1982 Arnold et al., 1994). These solvents have enabled such homogeneous17 reactions as O- and N-derivatization of cellulose and chitin (Williamson and McCormick, 1994) and selective site chlorination (Ball et al., 1994). Dimethylsulfoxide was the solvent in a homogeneous reaction of cellulose and paraformaldehyde, prior to isolation of purified cellulose (Johnson et al., 1975). In yet another outline, paraformaldehyde enabled superior quality extracts when the parent tissues were presoaked in this solution (Fasihuddin et al., 1988). 

IV. Correlations between Reaction with Cuprammonium and Other Reactions... 

Table II lists the behavior of a number of those substances in cuprammonium. It is apparent that reaction occurred at projected angles of 0° and 60°, but not at 120° or 180°. By referring to the oxygen-oxygen...

Since reaction with cuprammonium provides a measure of the relative position of adjacent hydroxyl groups it is of interest to compare cuprammonium data with existing information on other reactions in which two hydroxyl groups participate. 

One instance where correlation with cuprammonium data appears possible is the reaction between adjacent cis glycol groups and acetone to form isopropylidene derivatives. Although data on the kinetics and equilibria of isopropylidene formation are too meager to prove that reactivity with acetone parallels reactivity with cuprammonium, isolated observations support such a supposition. Knauf, Hann, and Hudson12 have noted the ease of formation of the acetone derivatives of D-mannosan, and this is one of the substances most reactive toward cuprammonium.6 Tipson13 has noted that the optically active 2,3-butanediols react with acetone more readily than the meso form, and this is the order in which these substances react with cuprammonium.14... 

Comparison of Shifts in Optical Rotation Due to Reaction with Acetone and with Cuprammonium... 

It has been shown that reaction with cuprammonium is greatly influenced by the position of a substituent group on the glucopyranoside ring.28-29 This is illustrated for monosaccharides of known structure... 

All the glucopyranosides substituted to restrict complex formation to the 2,3 position showed marked evidence of reaction with cuprammonium. This behavior would be compatible with ring conformations Cl, B2, and 3B except that three of the substances, the 4,6-ethylidene and 4,6-benzylidene compounds, could not exist in either the B2 or 3B conformations for steric reasons because of the spatial requirements of the second ring hence, these three substances must exist in the Cl conformation. 

Specific rotations in cuprammonium are based upon the weight of the glycol-containing molecule, not upon the weight of the copper glycol complex. This provision is necessary since the structures and molecular weights of the complexes are unknown. The optical rotations are the result of a reversible reaction, hence they are particularly dependent upon the concentrations of the reactants. The composition of the... 

The transformation of the sol into rayon came about through the reaction between the sol and the sulfuric acid. The method you used to make rayon in this experiment is the cuprammonium method. Chopped-up wood is the source of cellulose in the commercial application of this method. 

Daugirdas JT, Ing TS, Roxe DM, Ivanovich PT, Krumlovsky F, Popli S, McLaughlin MM. Severe anaphylactoid reactions to cuprammonium cellulose hemodialyzers. Arch Intern Med 1985 145(3) 489-94. 

The chemical reactions and mechanism of fixation of the am-moniacal preservatives such as ACA have not been studied extensively. The main mechanism of fixation is believed to be the formation of insoluble copper arsenate upon evaporation of the ammonia. However, the overall mechanism is undoubtedly more complex because cuprammonium ions react by ion exchange with functional groups, such as carboxyl, in wood (52). In addition, copper complexes can be formed with cellulose (52). 

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. 

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