Propylene oxide Hydroxypropyl cellulose

This paper examines two types of hydroxypropyl lignin based macromers, and these are illustrated schematically in Figure 1. Macromers with propylene oxide (PO) are formed by reducing the number of available hydroxyl groups on HPL followed by chain extension with PO and macromers with cellulose triacetate (CTA) are synthesized by attaching a monofunctional CTA chain to a limited number of terminal OH groups on HPL via a suitable grafting reaction. 

Materials. The hydroxypropyl cellulose (Klucel L ) used in this study was supplied by Hercules, Inc. The manufacturer reported a molar substitution of 4 propylene oxide units/anhydroglucose unit, and a nominal molecular weight of 105 g- mol-1. 

Methylcellulose is made by reaction of alkali cellulose with methyl chloride until the DS reaches 1.1—2.2. Hydroxypropylmethylcellulose [9004-65-3], the most common of this family of products, is made by using propylene oxide in addition to methyl chloride in the reaction MS values of the hydroxypropyl group in commercial products are 0.02—0.3. Use of 1,2-butylene oxide in the alkylation reaction mixture gives hydroxybutylmethylcellulose [9041-56-9, 37228-15-2] (MS 0.04—0.11). Hydroxyethylmethylcellulose [903242-2] is made with ethylene oxide in the reaction mixture. 

Hydroxyalkylcellulose. Reaction of cellulose with ethylene or propylene oxides produces hydroxyethyl or hydroxypropyl derivatives. By forming the hydroxyethyl derivative about the same ratio of hydrogen bonding sites to carbon atoms is provided as in the underivatized cellulose, but the substituent groups reduce the fit between polymer chains so that the derivative can be dissolved in water to produce stable solutions. The cellulose derivative has many of the solution properties of guaran. 

Methylcellulose solutions generally form gels at higher temperatures. The gelation temperature is increased when hydroxyethyl or hydroxypropyl groups are introduced into the methylcellulose (cf. Section 9.6.2). Hy-droxyethylmethylcellulose and hydroxypropylmethylcellulose are prepared industrially by the reaction of alkali cellulose first with ethylene oxide or propylene oxide and then with methyl chloride. Similarly, hydroxyethyl-ethylcellulose is prepared by consecutive ethylene oxide and ethyl chloride treatments. Cellulose ethers with both methyl and ethyl groups have also been manufactured. 

Hydroxypropyl cellulose is produced by substituting propylene oxide for hydroxyl groups on alkalized cellulose. This cellulosic derivative is soluble in cold... 

A purified form of cellulose is reacted with sodium hydroxide to produce a swollen alkali cellulose that is chemically more reactive than untreated cellulose. The alkali cellulose is then reacted with propylene oxide at elevated temperature and pressure. The propylene oxide can be substituted on the cellulose through an ether linkage at the three reactive hydroxyls present on each anhydroglucose monomer unit of the cellulose chain. Etherification takes place in such a way that hydroxypropyl substituent groups contain almost entirely secondary hydroxyls. The secondary hydroxyl present in the side chain is available for further reaction with the propylene oxide, and chaining-out may take place. This results in the... 

Low-substituted hydroxypropyl cellulose is manufactured by reacting alkaline cellulose with propylene oxide at elevated temperature. Following the reaction, the product is recrystallized by neutralization, washed, and milled. 

Conversions of alkali cellulose with ethylene oxide or propylene oxide, on the other hand, proceed without alkali consumption. The newly formed hydroxyl groups can also add on ethylene oxide or propylene oxide molecules. Commercially produced hydroxypropyl cellulose, with DR = 4, dissolves in water below 38 C. It can be thermoplastically processed and so is used to manufacture water-soluble packaging film, as an adjuvenant in pharmaceutics and confectionery, as a whipped cream stabilizer, as a binder for ceramics, as a suspending agent in emulsion polymerization, etc. 

The M.S. of a hydroxypropyl cellulose sample is 3.5. The D.P. of the cellulose used to prepare the sample was 120. Calculate the cellulose molecular weight and the grams of propylene oxide used in the synthesis. Assume the average number of hydroxypropyl units per side chain is 5. Calculate the D.S. 

Water-soluble substituted celluloses are another class of stabilizers used in the suspension polymerization, mainly in the manufacture of PVC. These stabilizers are soluble in both the vinyl chloride and the aqueous phase [20]. Ckjnsequently, the stabilizer can also affect the stabihty of the primary particles inside the polymerizing monomer droplets and, thus, the final porosity of the PVC particles. Hydroxypropyl methylcellulose (HPMC) is a cellulose ether, produced byreacting cellulose with propylene oxide and methyl chlorine in an alkaline medium. As a result, a fraction of the hydroxyl groups (hydrophilic groups) of the cellulose... 

Other propylene oxide molecules can add to the secondary hydroxyl groups that are formed. Commercial hydroxypropyl celluloses (HPC) have, on the average, about four propylene oxide units per glucose residue. 

Hydroxypropyl methyl cellulose (HPMC) Chloromethane and propylene oxide... 

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. 

Electroneutral starch ethers, i.e., hydroxyethyl starch (HES) and hydroxypropyl starch (HPS) are manufactured in analogy to the corresponding cellulose ethers by reaction of alkalinized starch with ethylene oxide or propylene oxide (Figure 4A.40). 

Guar is hydroxypropylated much like cellulose. The native guar gum is swollen in an aqueous nonsolvent, like aqueous 2-propanol and, under the influence of caustic, is derivatized with propylene oxide. The product is Altered, washed, and dried. Viscosity ranges for the HP-guar are controlled principally by the molecular weight of the native guar. 

HPC is synthesized by chemical modification of cellulose with an etherilying agent, propylene oxide that results in the introduction of hydroxypropyl side chains onto... 

Hydroxypropyl cellulose (HPC) E 463 Cellulose Chloromethane and propylene oxide Aerated toppings... 

Hydroxypropyl methyl cellulose (HPMC) E 464 Cellulose Propylene oxide Soya burgers, sausages, onion rings, potato croquettes, waffles, batters, coatings, doughnuts, gluten free bakery products, shampoo, lotions... 

A mixed ether, hydroxypropyl-methylcellulose, is also available. This is prepared by treating alkali cellulose with a mixture of methyl chloride and propylene oxide. Commercial grades of the polymer generally have a methoxy content of about 30% and a hydroxypropoxy content of about 5—10%. The mixed ether has increased organo-solubility and thermoplasticity over the methylcellulose counterparts. 

Low substituted-hydroxypropyl cellulose By reacting alkafine cellulose with propylene oxide Binder, Disintegrant... 

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. 

The reaction of cellulose with methylchloride or propylene oxide in the presence of a strong alkali introduces methyl or hydroxypropyl groups into cellulose (cf. Reaction 4.160). The degree of substitution (DS) is dependent on reaction conditions. 

The purified form of cellulose, obtained from cotton linters or wood pulp, is treated with sodium hydroxide solution to produce swollen alkali cellulose that is chemically more reactive than untreated cellulose. Reaction of the alkali cellulose with chloro-methane and propylene oxide produces methyl hydroxypropyl ethers of cellulose. Further purification of the fibrous reaction product is done and is grounded to fine, uniform powder or granules. 

Spherical silica particles containing retinol have been fabricated using O/ W/O multiple emulsion and the sol-gel method (Lee et al., 2001). O/W/O multiple emulsions were stabilized with hydroxypropyl cellulose (HPC) and surfactants such as Tween 20 and Span 80. In addition a polymeric stabilizer present in the intermediate aqueous phase was shown to improve the encapsulation efficiency. In the presence of polyvinyl alcohol the yield of encapsulation efficiency of retinol was 7%. With Pluronic P123 (a block copolymer of ethylene oxide propylene oxide) a yield of encapsulation of 31% could be reached. Figure 7.24 shows the retinol released profile from silica particles prepared in the O/W/O multiple emulsions and stabilized with different surfactant and different polymeric stabilizers in the intermediate aqueous phase. 

The reactions of ethylene and propylene oxides yield hydroxyethylcellulose and hydroxypropyl-cellulose (equation 6). Hydroxyethylcelluloses have been used in latex paints and in paper. ... 

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