Nonderivatizing solvents

Zhang, H., Wu, ]., Zhang, J., and He, J., l-Allyl-3-methylimidazolium chloride room temperature ionic liquid A new and powerful nonderivatizing solvent for cellulose. Macromolecules, 38,8272-827/ 2005. 

Cellulose is soluble in several derivatizing and nonderivatizing solvents [20,44,45,46]. These, in general, are solvents that modify OH-groups covalently or that form strong secondary bonds... 

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. 

Cellulose is soluble in a wide range of solvents from which it can be regenerated in unadulterated (crystalline) form [13]. This is accomplished in either fiber (especially staple fiber) form, in filament form or in any other form (sheets or films, sponges, etc.). Cellulose solvents are divided into derivatizing and nonderivatizing solvent systems [73]. The principle of deriva-... 

Other nonderivatizing solvents, such as LiCl-DMI (l,3-dimethyl-2-imidazolidin-one) and tetrabutylammonium fluoride trihydrate-Me2SO, have also been... 

Phottraithip W, Lin DQ, ShiF, Yao SJ (2011) Anovel method for the preparation of spherical cellulose-tungsten carbide composite matrix with NMMO as nonderivatizing solvent. J Appl Polym Sci 121 2985-2992... 

Polyethers. Polyethers such as polyethylene oxide (PEO) and polypropylene oxide (PPO) have been used for ESI-MS calibration [10,11,19]. The predominant ions for these calibrants are cation attachments, and sodium attachment is frequently observed, due to traces of sodium in solvents and glassware. The positive-ion ESI mass spectra of PEO and PPO are characterized by abundant [M + nNa]n+ and some [M + ] + species. Macrocyclic polyethers and crown ethers were also used as ESI-MS calibrants [11]. In general, nonderivatized polyethers show the following drawbacks when used as calibrations solutions (1) they are difficult to flush out of the ion source, (2) they generate complex mass spectra resulting from the presence of several different cation sources, and... 

A solvent blank is used to eliminate the possibility of contamination arising from outside the sample, for example, from the syringe or from the instrument. It is recommended to use the sample solvent as solvent blank and run this test at the beginning and at the end of each sample series and whenever contamination is suspected. The memory effect is possible, for example, in the analysis of alkyl phosphonic acids. If the derivatization of these chemicals has not been complete, the nonderivatized acids are adsorbed on the injector liner. A silylation reagent may in such case react in situ with the adsorbed acids in the liner yielding false positive results. 

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