Cellulose partially hydroxyethylated

By this means, the distribution of substituents in 0-(2-hydroxyethyl)-cellulose, partially methylated celluloses, " 0-ethylcellulose, and a partially 0-(carboxymethyl)ated cellulose has been established. The combined result of the investigation gives a measure of the relative reactivities of the hydroxyl groups at C-2, C-3, and C-6 toward a variety of alkylating agents. These are summarized in Table II. 

Synonyms Cellulose hydroxyethylate Cellulose hydroxyethyl ether Cellulose, 2-hydroxyethyl ether HEC HE cellulose Hetastarch 2-Hydroxyethyl cellulose Hydroxyethyl cellulose ether 2-Hydroxyethyl cellulose ether Hydroxyethyl ether cellulose Hydroxyethyl starch Definition Partially substituted poly(hydroxyethyl) ether of cellulose Empirical CsH Oe Formula C6H,02(0H)20CH2CH20H... 

In VCM suspension polymerisation, water and liquid VCM in approximately equal phase volumes are stirred together with a water-soluble polymer such as a partially hydrolysed polyvinyl acetate (PVA) or a substituted cellulose eg hydroxypropyl cellulose, hydroxybutyl methyl cellulose, ethyl hydroxyethyl cellulose. The droplet size distribution obtained is the result of two competing processes, droplet break-up and coalescence break-up occurs in the turbulent shear field around the impeller tip, coalescence in the regions of the reactor which are distant from the impeller. This process continues until some equilibrium droplet size distribution is obtained this determines the initial size of polymerising droplets. The initial droplet size distribution depends on (a) stirrer type (b) stirrer speed (c) reactor configuration and position of stirrer in the reactor (d) nature and concentration of water-soluble polymeric additives. 

Fluid loss additives such as solid particles and water-thickening polymers may be added to the drilling mud to reduce fluid loss from the well bore to the formation. Insoluble and partially soluble fluid loss additives include bentonite and other clays, starch from various sources, crushed walnut hulls, lignite treated with caustic or amines, resins of various types, gilsonite, benzoic acid flakes, and carefully sized particles of calcium borate, sodium borate, and mica. Soluble fluid loss additives include carboxymethyl cellulose (CMC), low molecular weight hydroxyethyl cellulose (HEC), carboxy-methYlhydroxyethyl cellulose (CMHEC), and sodium acrylate. A large number of water-soluble vinyl copolymers and terpolymers have been described as fluid loss additives for drilling and completion fluids in the patent literature. However, relatively few appear to be used in field operations. 

Fig. 39.—,3C-N.m.r. Spectra of A, 0-(Carboxymethyl)cellulose (d.s. 0.7), Partially Degraded by Cellulase, in D20 at 30° (R, signal of reducing-end residue S represents a 13C nucleus bonded to an alkoxyl group) and of B, 0-(2-Hydroxyethyl)cellulose (d.s. 0.8), Partly Degraded by Cellulase, in D20 at 30°. (R, signal due to reducing-end residue S represents a 13C nucleus bonded to an alkoxyl group.)...

The most widely used synthetic and natural enhanced oil recovery polymers, such as partially hydrolyzed polyacrylamide, carboxymethyl(ethyl) cellulose, polysaccharides, or xanthan gums, are not suitable for high-temperature reservoirs (> 90 °C) with high-density brine fluid due to excessive hydrolysis and precipitation [277]. The main advantages of polymeric betaines over the mentioned standard polymers are (1) thermostability (up to 120 °C) (2) brine compatibility and (3) viscosification in brine solution [278]. Carbobetaines grafted onto hydroxyethyl cellulose were tested as a drilling-mud additive for clay hydration inhibition and mud rheological control [279]. An increase in the content of carbobetaine moieties resulted in an enhanced inhibitive abiUty, especially for sahne mud. 

Equation 13 was used to calculate the derivative and the partial specific volume of hydroxypropyl cellulose was taken as that of the hydroxyethyl cellulose, which is provided in ref 43. The results are plotted in Figures ID, 2D, and 3D. 

Solubility hydroxyethyl cellulose is soluble in either hot or cold water, forming clear, smooth, uniform solutions. Practically insoluble in acetone, ethanol (95%), ether, toluene, and most other organic solvents. In some polar organic solvents, such as the glycols, hydroxyethyl cellulose either swells or is partially soluble. 

Hydroxyethyl cellulose is insoluble in most organic solvents. It is incompatible with zein and partially compatible with the following water-soluble compounds casein gelatin methyl-cellulose polyvinyl alcohol, and starch. 

When the hydrogen atom of the hydroxyl group on C6 of cellulose is partially substituted with a hydroxyethyl (-CH CH OH) group in a reaction with ethylene oxide under alkaline condition, hydroxyethyl cellulose (HEC) is produced. So far there are no known testing methods for HEC detection. However, if one wants to distinguish CMC from HEC, an ion tolerance test can be conducted. CMC is anionic and can be precipitated from an aqueous solution with a cationic surfactant. Since HEC is non-ionic, its aqueous solution is compatible with cationic surfactants. Based on the same ionic tolerance principle, a high salt concentration can precipitate CMC, not HEC. 

Definition Partially substituted poly(hydroxyethyl) ether of cellulose Empincal CsHuOe Formula C6H702(0H)20CH2CH20H Properties Wh. free-flowing powd., odorless, tasteless nonionic insol. in org. solvs. sol. in hot... 

This is a partially 0-mcthylated and partly O-(hydroxyethylated) cellulose. It is in.soluble in hot water and organic solvents but dissolves in cold water. It is used as an excipient in a wide range of pharmaceutical formulations mainly as a coating for solid dosage forms and granules and as a su.spending agent for disperse systems (a. 13). 

Characteristics of the n.m.r. spectra of methyl-, carboxymethyl-, and hydroxyethyl-cellulose ethers have been examined at 22.6 MHz. Partial pre-depolymerization with acid or cellulase proved to be a requisite step. The spectra permitted an assessment of the degree of substitution at individual positions of the D-glucose residues and afforded other information in agreement with data obtained by other methods. 

Table 1. Partial specific volume of hydroxyethyl cellulose. ...

Xiao Q, Yan S, Rogausch KD, Petermann J, Huang Y. Ring-banded spherulites in poly(e-caprolactone) blended with hydroxyethyl cellulose acetate as an indication for partial miscibility. J Appl Polym Sci 2001 80 1681-1686. 

Definition Partially substituted poly(hydroxyethyl) ether of cellulose... 

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