Propylene oxide, properties

Definition Starch crosslinked with sodium trimetaphosphate or phosphorus oxychloride and etherified with propylene oxide Properties Wh. or nearly wh. powd. or gran. flakes, amorphous powd., or coarse particles if pregelatinized... 

Isoprene [78-79-5] (2-methyl-1,3-butadiene) is a colorless, volatile Hquid that is soluble in most hydrocarbons but is practically insoluble in water. Isoprene forms binary azeotropes with water, methanol, methylamine, acetonitrile, methyl formate, bromoethane, ethyl alcohol, methyl sulfide, acetone, propylene oxide, ethyl formate, isopropyl nitrate, methyla1 (dimethoxymethane), ethyl ether, and / -pentane. Ternary azeotropes form with water—acetone, water—acetonitrile, and methyl formate—ethyl bromide (8). Typical properties of isoprene are Hsted in Table 1. 

Propylene oxide is a colorless, low hoiling (34.2°C) liquid. Table 1 lists general physical properties Table 2 provides equations for temperature variation on some thermodynamic functions. Vapor—liquid equilibrium data for binary mixtures of propylene oxide and other chemicals of commercial importance ate available. References for binary mixtures include 1,2-propanediol (14), water (7,8,15), 1,2-dichloropropane [78-87-5] (16), 2-propanol [67-63-0] (17), 2-methyl-2-pentene [625-27-4] (18), methyl formate [107-31-3] (19), acetaldehyde [75-07-0] (17), methanol [67-56-1] (20), ptopanal [123-38-6] (16), 1-phenylethanol [60-12-8] (21), and / /f-butanol [75-65-0] (22,23). 

Table 1. Physical Property Data for Propylene Oxide...

Table 2. Propylene Oxide Physical Property Data as a Function of Temperature ...

Polyall lene Oxide Block Copolymers. The higher alkylene oxides derived from propjiene, butylene, styrene (qv), and cyclohexene react with active oxygens in a manner analogous to the reaction of ethylene oxide. Because the hydrophilic oxygen constitutes a smaller proportion of these molecules, the net effect is that the oxides, unlike ethylene oxide, are hydrophobic. The higher oxides are not used commercially as surfactant raw materials except for minor quantities that are employed as chain terminators in polyoxyethylene surfactants to lower the foaming tendency. The hydrophobic nature of propylene oxide units, —CH(CH2)CH20—, has been utilized in several ways in the manufacture of surfactants. Manufacture, properties, and uses of poly(oxyethylene- (9-oxypropylene) have been reviewed (98). 

Two propylene oxide elastomers have been commercialized, PO—AGE and ECH—PO—AGE. These polymers show excellent low temperature flexibihty and low gas permeabihty. After compounding, PO—AGE copolymer is highly resiUent, and shows excellent flex life and flexibiUty at extremely low temperatures (ca —65°C). It is slightly better than natural mbber in these characteristics. Resistance to oil, fuels, and solvents is moderate to poor. Wear resistance is also poor. Unlike natural mbber, PO—AGE is ozone resistant and resistant to aging at high temperatures. The properties of compounded ECH—PO—AGE he somewhere between those of ECH—EO copolymer and PO—AGE copolymer (22). As the ECH content of the terpolymer increases, fuel resistance increases while low temperature flexibihty decreases. Heat resistance is similar to ECH—EO fuel resistance is similar to polychloroprene. The uncured mbber is soluble in aromatic solvents and ketones. 

The initiator usually constitutes less than 1% of the final product, and since starting the process with such a small amount of material in the reaction vessel may be difficult, it is often reacted with propylene oxide to produce a precursor compound, which may be stored until required [6]. The yield of poloxamer is essentially stoichiometric the lengths of the PO and EO blocks are determined by the amount of epoxide fed into the reactor at each stage. Upon completion of the reaction, the mixture is cooled and the alkaline catalyst neutralized. The neutral salt may then be removed or allowed to remain in the product, in which case it is present at a level of 0.5-1.0%. The catalyst may, alternatively, be removed by adsorption on acidic clays or with ion exchangers [7]. Exact maintenance of temperature, pressure, agitation speed, and other parameters are required if the products are to be reproducible, thus poloxamers from different suppliers may exhibit some difference in properties. 

Propylene oxide is similar in its structure to ethylene oxide, but due to the presence of an additional methyl group, it has different physical and chemical properties. It is a liquid that boils at 33.9°C, and it is only slightly soluble in water. (Ethylene oxide, a gas, is very soluble in water). 

A particularly interesting system for the epoxidation of propylene to propylene oxide, working under pseudo-heterogeneous conditions, was reported by Zuwei and coworkers [61]. The catalyst, which was based on the Venturello anion combined with long-chained alkylpyridinium cations, showed unique solubility properties. I11 the presence of hydrogen peroxide the catalyst was fully soluble in the solvent, a 4 3 mixture of toluene and tributyl phosphate, but when no more oxidant was left, the tungsten catalyst precipitated and could simply be removed from the... 

Epoxides such as ethylene oxide and higher olefin oxides may be produced by the catalytic oxidation of olefins in gas-liquid-particle operations of the slurry type (S7). The finely divided catalyst (for example, silver oxide on silica gel carrier) is suspended in a chemically inactive liquid, such as dibutyl-phthalate. The liquid functions as a heat sink and a heat-transfer medium, as in the three-phase Fischer-Tropsch processes. It is claimed that the process, because of the superior heat-transfer properties of the slurry reactor, may be operated at high olefin concentrations in the gaseous process stream without loss with respect to yield and selectivity, and that propylene oxide and higher... 

Phosphoric acid esters based on alkylene oxide adducts are of great interest. Their properties can be altered by the length and structure of the hydrophobic alkyl chain. But they are also controlled by the kind and length of the hydrophilic alkyleneoxide chain. The latter can easily be tailored by selection between ethylene oxide and propylene oxide and by the degree of alkoxylation. 

Thermoplastic xylan derivatives have been prepared by in-hne modification with propylene oxide of the xylan present in the alkaline extract of barley husks [424,425]. Following peracetylation of the hydroxypropylated xylan in formamide solution yielded the water-insoluble acetoxypropyl xylan. The thermal properties of the derivative quahfy this material as a potential biodegradable and thermoplastic additive to melt-processed plastics. Xylan from oat spelts was oxidized to 2,3-dicarboxyhc derivatives in a two-step procedure using HI04/NaC102 as oxidants [426]. 

Statistical and block copolymers based on ethylene oxide (EO) and propylene oxide (PO) are important precursors of polyurethanes. Their detailed chemical structure, that is, the chemical composition, block length, and molar mass of the individual blocks may be decisive for the properties of the final product. For triblock copolymers HO (EO) (PO)m(EO) OH, the detailed analysis relates to the determination of the total molar mass and the degrees of polymerization of the inner PPO block (m) and the outer PEO blocks (n). 

Studies have been made of the elastic (time-independent) properties of single-phase polyurethane elastomers, including those prepared from a diisocyanate, a triol, and a diol, such as dihydroxy-terminated poly (propylene oxide) (1,2), and also from dihydroxy-terminated polymers and a triisocyanate (3,4,5). In this paper, equilibrium stress-strain data for three polyurethane elastomers, carefully prepared and studied some years ago (6), are presented along with their shear moduli. For two of these elastomers, primarily, consideration is given to the contributions to the modulus of elastically active chains and topological interactions between such chains. Toward this end, the concentration of active chains, vc, is calculated from the sol fraction and the initial formulation which consisted of a diisocyanate, a triol, a dihydroxy-terminated polyether, and a small amount of monohydroxy polyether. As all active junctions are trifunctional, their concentration always... 

Hydronium ion, 14 23 Hydroperoxidates, 18 411 Hydroperoxide process, for propylene oxide manufacture, 20 798, 801-806 Hydroperoxides, 14 281, 290-291 18 427-436 alkylation of, 18 445 a-oxygen-substituted, 18 448-460 chemical properties of, 18 430 433 decomposition of, 14 279 18 431-432 liquid-phase epoxidation with, 10 656 physical properties of, 18 427-430 preparation by autoxidation, 18 434 synthesis of, 18 433-435 Hydrophile-lipophile balance system,... 

To comply with environmental legislation, coatings formulators have reformulated to water-based systems, which has wide-ranging effects on the properties of their products. Reformulating with non-hazardous air pollutants solvents such as propylene-oxide-based glycol ethers helps reduce VOC content, and is the subject of this detailed paper. 6 refs. 

Polypropylene ether) polyol is the single most important product from propylene oxide and enjoys a predominant position in polyurethane applications. The ether linkages are very abundant in these polyols and they contribute to the physical and chemical properties in many applications such as surfactant action and hydrogen-bond formation. 

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