Compounds cellulose derivatives

The Diacel columns can be used for the separation of a wide variety of compounds, including aromatic hydrocarbons having hydroxyl groups, carbonyls and sulfoxides, barbiturates, and P-blockers (35,36). There are presendy nine different cellulose derivative-based columns produced by Diacel Chemical Industries. The different columns each demonstrate unique selectivities so that a choice of stationary phases is available to accomplish a separation. 

In this context, the enantiomeric pair containing the eutomer of cyclothiazide can be resolved by HPLC on cellulose-derived coated CSPs. Nevertheless, the poor solubility of this compound in solvents compatible with this type of support makes this separation difficult at preparative scale. This operation was achieved with a cellulose carbamate fixed on allylsilica gel using a mixture of toluene/acetone as a mobile phase [59]. 

Levoglucosenone, a cellulose-derived a,(3-unsaturated ketone, is an interesting material because it is both chiral and contains an activated double bond. This compound has been used... 

Concerning detectability of lignin and cellulose derived fragments, MCA has considerable advantages. Such compounds are often poorly chro-mogenic some have no chromogens at all, or are poorly prochromogenic,... 

Many PSPs are composed of probe dyes, such as polycyclic aromatic hydrocarbons (e.g., pyrene) and coordination compounds (e.g., platinum por-phryins and ruthenium(II) polypyridyl complexes) immobilized in various gas permeable polymer films such as silicon polymer, organic glassy polymers (e.g., poly(methylmethacrylate), polystyrene), fluorinated polymers, or cellulose derivatives such as ethyl cellulose [9,10]. As probe molecules interact with polymer matrices directly, the properties of PSPs strongly depend on the properties of polymer matrices. The oxygen permeability of polymer matrix is an especially important factor for highly sensitive PSP. 

Jones (1996) recommended a holistic approach to fat replacement, whereby the spherical shape of a fat droplet as well as the properties of a fat are mimicked by using hydrophobic compounds. Accordingly, the least amphiphilic saccharides with the shortest persistence lengths, e.g., pectin and the cellulose derivatives (Lapasin and Pricl, 1995), are suitable models. By their nature, the intermediate DP saccharides fulfil the requirement. 

Bikales, N. M. (1971). Ethers from a,jS-unsaturated compounds. In "Cellulose and Cellulose Derivatives" (N. M. Bikales and L. Segal, eds.), Part V, pp. 811 -833. Wiley (Interscience), New York. 

One recent trend has been away from using a photochromic dye itself merely as an individual component of a solution, polymer film or bulk polymer matrix. Instead, the photochromic is chemically linked to a polymer, which may be a natural polymer such as a cellulose derivative, an enzyme, a protein, or synthetic polymers from acrylates, urethanes, and vinyl compounds. The properties of the polymer can then be modified by external irradiation, and conversely, the properties of the photochromic are modified by the polymer. A recent biochemical example is the photocontrolled binding of monosaccharides to concanavalin A (Con A) modified with spiropyran units.208... 

Usually, a gradient of ethanol is superimposed on the aforementioned salt gradient, to lessen the affinity of trityl-containing compounds for the cellulose derivative, but a drawback with this procedure is that flow rates then tend to decrease. Relevant fractions... 

Being ionic compounds, cellulose sulfates have ion exchange properties. They have been recommended for use as cation exchangers [42,47,48]. Sodium ceilulose sulfates are also known to have blood anticoagulant activity. The correlation of molecular characteristics of these derivatives with their anticoagulant activity has been investigated [49]. However, it has been reported that celiuiose suifate exhibits a certain toxicity [50]. 

We have systematically studied the possibility rf preparing various types of cellulose derivatives containing triple boiKl. Certain chemical transformations of the resultii compounds have also been accomplished. 

Among the polymers used in lens comfort solutions are polyvinyl alcohol, polyvinylpyrrolidone, dextran, and various cellulose derivatives such as hydroxyethyl cellulose, hydroxypropyl cellulose, and hydroxypropyl methylcellulose. Surfactants include certain poloxamer and poloxamine compounds. Other normal components comprise appropriate preservative(s) as well as buffering and tonicity-adjusting agents. 

The pyrolysis oil collected between 200 to 275 C in the second step was 18.14 % by wt. on an anhydrous wood basis and corresponded to the hemicelluloses degradation . In general, hemicelluloses decompose to yield furans and its derivatives as well as a series of aliphatic carboxylic acids. Hardwoods are composed of pentosan-based hemicelluloses, while hexosan-based hemicelluloses are found in softwoods. Hardwood produces more low molecular weight carboxylic acids and furans than softwood upon decomposition . In contrast, hardwood contains a lower quantity of fatty acids than softwood. Cl - C6 carboxylic acids, fatty acids (e.g. Cia), fiiran and derivatives were identified in this fraction. In the second pyrolysis step, a little rearrangement of the lignin polymer occurred which was based on the formation of small amount of phenolic compounds 0,395 % by wt., anhydrous wood basis). The main components of this fraction are listed in Table 2. Betulin and lupeol were abundant in this fraction. Furthermore, levoglucosan which has been reported earlier as a major compound in the cellulose-derived pyrolysis oils, was identified in the second... 

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