Hydroxypropyl ether of cellulose

Etherification. Carbohydrates are involved in ether formation, both intramoleculady and intermoleculady (1,13). The cycHc ether, 1,4-sorbitan, an 1,4-anhydroalditol, has already been mentioned. 3,6-Anhydro-a-D-galactopyranosyl units are principal monomer units of the carrageenans. Methyl, ethyl, carboxymethyl, hydroxyethyl, and hydroxypropyl ethers of cellulose (qv) are all commercial materials. The principal starch ethers are the hydroxyethyl and hydroxypropylethers (see Cellulose ethers Starch). 

HYDROXYPROPYLAMINE see PMM250 (3-HYDROXYPROPYL)BENZENE see HHP050 p-HYDROXYPROPYL BENZOATE see HNU500 HYDROXYPROPYL CELLULOSE see HNVOOO HYDROXYPROPYL ETHER of CELLULOSE see HNVOOO... 

The PhEur 2005 and USPNF 23 describe hydroxypropyl cellulose as a partially substituted poly(hydroxypropyl) ether of cellulose. It may contain not more than 0.6% of silica or another suitable anticaking agent. Hydroxypropyl cellulose is commercially available in a number of different grades that have various solution viscosities. Molecular weight has a range of 50 000-1 250 000 see also Section 10. 

The USPNF 23 describes low-substituted hydroxypropyl cellulose as a low-substituted hydroxypropyl ether of cellulose. When dried at 105°C for 1 hour, it contains not less than 5.0% and not more than 16.0% of hydroxypropoxy groups (—OCH2CHOHCH3). Low-substituted hydroxypropyl cellulose is commercially available in a number of different grades that have different particle sizes and substitution levels. 

A purified form of cellulose, obtained from cotton linters or wood pulp, is reacted with sodium hydroxide solution to produce a swollen alkali cellulose that is chemically more reactive than untreated cellulose. The alkali cellulose is then treated with chloromethane and propylene oxide to produce methyl hydroxypropyl ethers of cellulose. The fibrous reaction product is then purified and ground to a fine, uniform powder or granules. 

Synonyms cas 9004-64-2 hydroxypropyl ether of cellulose klucel Hydroxytriphenylstannane... 

Synonyms Cellulose, 2-hydroxypropyl ether HPC Hydroxypropyl ether of cellulose Hyprolose Oxypropylated cellulose Definition Partially substituted poly(hydroxypropyl) ether of cellulose Properties Off-wh. gran, powd., odorless, tasteless sol. in cold water, methanol, ethanol, many polar org. soivs. insol. in water > 37.7 C ... 

Synonyms Cellulose, 2-hydroxypropyl ether HPC Hydroxypropyl ether of cellulose Hyprolose Oxypropylated cellulose... 

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

Hydroxypropyl ether of cellulose. See Hydroxypropyl cellulose Hydroxypropyl ether guar gum. See Hydroxypropyl guar Hydroxypropylglycerin Properties Pale straw-colored liq. sol. in water and methanol dens. 1.084 pour pt. -23 C flash pt. 193 C ref. index 1.459 Precaution Combustible Uses Intermediate for alkyd resins and polyesters plasticizer for cellulosics, glue, starch, etc. 

A number of compounds of this type are in use and they consist of methyl (and in some cases ethyl or hydroxypropyl)ethers of cellulose they are characterised by their alkoxyl content. A general method for the determination of methoxyl groups is as follows ... 

In context with RR, the following w. should be mentioned alginates (- sodium alginate) ->car-boxymethyl cellulose - carrageenan - guar gum - locust gum gum arabic - hydroxyethyl cellulose - hydroxypropyl cellulose - methyl-cellulose - mixed ethers of cellulose ->pectin, - starches, starch esters, - starch ethers, - oxidized starches, -+dextrins, - starch hydrolysis products, - maltodextrins and their derivatives, - dextran, - scleroglucan, - maltodextrins and - xanthan. 

A possible way to lower the costs of fibers and films of regenerated cellulose would be to run cellulose through a twin-screw ultrasonic extruder with a minimum of solvent and pass the extrudate through a stream of hot air to recover the solvent for reuse. This stronger cellophane could be used in place of many plastic films used today. A great number of derivates of cellulose have been made. Methyl, ethyl, carboxymethyl, hydroxyethyl, and hydroxypropyl ethers are made commercially today. These are used as water-soluble polymers, except for ethylcellulose, which is a tough plastic used in screwdriver handles and such. 

Wirick MG. Study of the enzymic degradation of CMC and other cellulose ethers. / Polym Sci 1968 6(Part A-1) 1965-1974. Anonymous. Final report on the safety assessment of hydroxy-ethylcellulose, hydroxypropylcellulose, methylcellulose, hydroxypropyl methylcellulose and cellulose gum. / Am Coll Toxicol 1986 5(3) 1-60. 

Chloro-2-hydroxypropyl derivatives of such polysaccharides as cellulose and cross-linked dextran (Sephadex) may be prepared by treatment with epichlorohydrin in boron trifluoride etherate. These 3-chloro-2-hydroxypropylated polysaccharides may, in turn, react with ammonia, or primary, secondary, or tertiary amines, and the resultant derivatives of cellulose and Sephadex LH-20, particularly an 0-[3-(di-butylamino)-2-hydroxypropyl] derivative of the latter, are useful anion-exchangers. In the amination procedure, between 50 and 100% of the chlorine atoms are utilized, except in the reaction with tertiary... 

Synonyms Carbohydrate gum Cellulose hydroxypropyl methyl ether Cellulose 2-hydroxypropyl methyl ether HPMC Hypromellose Methyl hydroxypropyl cellulose MHPC Definition Propylene glycol ether of methyl cellulose Properties Wh. gran, powd. sol. in most polar soivs., cold water swells in water to produce a clear to opalescent vise, colloidal sol n. insol. in hot water and in anhyd. alcohol, ether, chloroform nonionic Toxicoiogy LD50 (IP, rat) 5200 mg/kg mildly toxic by IP route TSCA listed... 

Poly (2-hydroxypropyl. Me) ether Hydro-xypropyl methyl cellulose. HPMC. E463. Hypromellose, USAN. Hydroxypropyl-methylcellulose, JAN. Cellulose hydro-xypropyl methyl ether, BAN, INN [9(X)4-65-3] Prepared by etherification of alkaline cellulose with methyl chloride and propylene oxide. Commercial samples have methyl DS values of 1.1-2.0 and hydroxypropyl MS values of 0.1 - 1.0. Thickening and binding agent with widespread industrial uses in adhesives, building products, films, protective creams and colloids. Approved for food use in US and EU. Used in deep fried batters. Shows better water solubility and electrolyte tolerance than methylcellulose. Component of artificial tears. 

FIGURE 10.4 Reactions making cellulose ethers, (a) Reaction of cellulose to make sodium cellulose. (b) Reaction of sodium cellulose with chloroacetic acid to make sodium carboxymethyl cellulose. (c) Reaction of sodium cellulose with, e.g., methyl chloride to make, e.g., methyl cellulose, (d) Reaction of sodium cellulose with propylene oxide to make hydroxypropyl cellulose. 

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