D,l-Propylene oxide

Saba,R.G., Sauer,J. A., Woodward,A.E. Dynamic shear behavior of poly (y-benzyl L-glutamate), poly(D, L-propylene oxide), and polyfethyl vinyl ether). J. Polymer Sd. A1, 1483 (1963). 

When D,L-propylene oxide was used in a similar preparation, an optically inactive product formed. 

Propylene oxide has an asymmetric carbon atom. The normal commercial epoxide is a racemic mixture of the d- and 1-isomers. Osgan and Price did extensive work with both the 1-propylene oxide and the d,l-propylene oxide in both potassium hydroxide and ferric chloride/propylene oxide-initiated polymerizations. Their results are summarized in Table 5 (48). C. C. Price and coworkers first demonstrated that polymerization of pure 1-propylene oxide with an anhydrous potassium hydroxide (solid KOH) initiator led to a crystalline, rather than the usual amorphous, liquid, polymer. After extensive study by a number of researchers (69), this polymerization was shown to proceed by a stepwise anionic mechanism. The uses found for polymers of propylene oxide largely have been those requiring the amorphous polymer in elastomeric applications. Stereospecificity, however, has proved to be a key tool in understanding the polymerization mechanisms. 

Special relationships apply, however, when configurationally different but constitionally identical monomers are copolymerized. An example of this is the polymerization of D- and L-propylene oxide mixtures. Here, it is important to distinguish sharply between stereospecific and stereoselective polymerizations. The meaning of these two terms is not the same as the corresponding meaning of stereospecific and stereoselective reactions in low-molar-mass organic chemistry. 

Hydrolyzes in water forming l-chloro-2,3-hydroxypropane which may hydrolyze forming HCl and the intermediate l-hydroxy-2,3-propylene oxide or l-chloro-2,3-hydroxypropane. The oxide may continue to hydrolyze forming glycerol (Kollig, 1993). The estimated half-life for this reaction at 20 °C and pH 7 is 8.2 d (Mabey and Mill, 1978). 

Polymer Poly(D- propylene oxide) Cellulose triacetate Cellulose diacetate Polyfy-methyl L-glutamate) (a-helix)... 

A suspension of 37.3 g (0.1 mol) of 7p-amino-3-methoxy-3-cephem-4-carboxylic acid hydrochloride dioxanate in 500 ml methylene chloride is stirred for 15 minutes at room temparature under an argon atmosphere and treated with 57.2 ml (0.23 mol) of bis-(trimethylsilyl)acetamide. After 45 minutes the faintly yellow slightly turbid solution is cooled to 0°C and treated within 10 minutes with 31.29 (0.15 mol) of D-a-amino-a-(l,4-cyclohexadienyl)-acetyl chloride hydrochloride. Thirty minutes thereafter 15 ml (about 0.21 mol) of propylene oxide is added and the mixture is further stirred for 1 hour at 0°C ... 

Du Y, Cai F, Kong D-L et al (2005) Organic solvent-free process for the synthesis of propylene carbonate from supercritical carbon dioxide and propylene oxide catalyzed by insoluble ion exchange resins. Green Chem 7(7) 518-523... 

D. L. Trent, Propylene oxide, in Kirk Othmer Encyclopedia of Chemical Technology, on-line edition, John Wiley Sons, New York, 2001. 

An attractive route to (/ )- and (5)-2-amino-3-phosphonopropanoic acid (AP-3) involves the intermediacy of serine-deiived P-lactones. The nucleophilic addition of trimethyl phosphite to (/ )- and (5)-A-(ierZ-butoxycarboiiyl)-3-amino-2-oxetanone at 70°C for 42 h gives the (R)- and (5)-methyl A-(tert-butoxycarbonyl)-2-amino-3-(dimethoxyphosphinyl)propanoates in excellent yields. Exhaustive acid hydrolysis of the (S)- and (7 )-isomers, followed by treatment with propylene oxide, affords the corresponding (R)- and (S)-2-amino-3-phosphonopropanoic acids as their zwitterions (d- and l-AP-3) (Scheme 8.42). ... 

Figure 5.27 summarizes our synthesis of (/ )-(+)-143, the opposite enantiomer of the naturally occurring (-)-nocardione B. Commercially available 5-methoxy-l-tetralone (A) was treated with lithium hexam-ethyldisilazide (LiHMDS), followed by (S )-propylene oxide (B) in the presence of scandium triflate in dry toluene to give hydroxy ketone C. The hydroxy group of C was protected as 2,2,2-trichloroethoxycarbonate to give D, and its alicyclic ring was oxidized with selenium dioxide to give E. 

In the presence of chiral polymerization catalysts, enantiomeric monomers arc consumed at different rates (Scheme 75). Enantiomer-selective polymerization of racemic propylene oxide catalyzed by a diethylzinc-(-l-)-bomeol system is a classical example of such kinetic resolution (i7<5). The polymeric product has an la]D of +7.4°. The mechanism... 

D. R. Jackson and L. G. Lundsted, U.S. Patent 2,677,700 (1954). Product corresponds to about 11.0 propylene oxide groups/mole of nonylphenol. 

Landau, R., Brown, D Russell, J.L., Kollar, J Epoxidation of Olefins, presented at Symposium on New Concepts and Techniques in Oxidation of Hydrocarbons, 7th World Petroleum Congress, Mexico City, April 1967 Landau, R., Sullivan, G.A., Brown, D., Propylene Oxide by Co-Product Processes, C/iem/pc/i, Oct. I979, p. 602... 

DER D Errico, G., Paduano, L., and Khan, A., Temperature and concentration effects on supramolecular aggregation and phase behavior for poly(propylene oxide)-f>-poly(ethylene oxide)-i-poly(propylene oxide) copolymers of different composition in aqueous mixtures, J. Coll. Interface Sci., 279, 379, 2004. 

ROD Rodrigues, G.D., Silva, M. do C.H. da, Silva, L.H.M. da, Teixeira, L. da S., and Andrade, V.M. de, Liquid-liquid phase equiUbrium of triblock copolymer L64, poly(ethylene oxide-Z)-propylene oxide- >-ethylene oxide), with sulfate salts from (278.15 to 298.15) K, J. Chem. Eng. Data, 54, 1894, 2009. 

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