Propylene oxide catalyzed

In 1955, Pruitt and Baggett (4,5) reported the polymerization of propylene oxide catalyzed by the reaction product of ferric chloride and propylene oxide, i.e., Pruitt-Baggett catalyst . Polypropylene oxide obtained from DL-monomer could be fractionated into two parts, one rubbery and another resinous. The latter fraction gave a discrete crystalline X-ray diffraction pattern. 

In the presence of chiral polymerization catalysts, enantiomeric monomers are consumed at different rates (Scheme 75). Enantiomer-selective polymerization of racemic propylene oxide catalyzed by a diethylzinc-(-f)-bomeol system is a classical example of such kinetic resolution H 176). The polymeric product has an [a]D of +7.4°. The mechanism... 

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... 

Peng, J. Deng, Y. Cycloaddition of Carbon Dioxide to Propylene Oxide Catalyzed by Ionic Liquids. NewJ. Chem. 2001,25, 639-641... 

Alternatively, the AC may react with oxiranes (eg, ethylene oxide (R" = H) or propylene oxide (R" = CH3) (eq. 3)) this is a catalyzed addition and requires a much lower caustic-to-ceUulose ratio than is used in direct displacement (eq. 2). 

The addition of an oxygen atom to an olefin to generate an epoxide is often catalyzed by soluble molybdenum complexes. The use of alkyl hydroperoxides such as tert-huty hydroperoxide leads to the efficient production of propylene oxide (qv) from propylene in the so-called Oxirane (Halcon or ARCO) process (79). 

Although this process has not been commercialized, Daicel operated a 12,000-t/yr propylene oxide plant based on a peracetic acid [79-21-0] process during the 1970s. The Daicel process involved metal ion-catalyzed air oxidation of acetaldehyde in ethyl acetate solvent resulting in a 30% peracetic acid solution in ethyl acetate. Epoxidation of propylene followed by purification gives propylene oxide and acetic acid as products (197). As of this writing (ca 1995), this process is not in operation. 

Recently (79MI50500) Sharpless and coworkers have shown that r-butyl hydroperoxide (TBHP) epoxidations, catalyzed by molybdenum or vanadium compounds, offer advantages over peroxy acids with regard to safety, cost and, sometimes, selectivity, e.g. Scheme 73, although this is not always the case (Scheme 74). The oxidation of propene by 1-phenylethyl hydroperoxide is an important industrial route to methyloxirane (propylene oxide) (79MI5501). 

The manufacture and uses of oxiranes are reviewed in (B-80MI50500, B-80MI50501). The industrially most important oxiranes are oxirane itself (ethylene oxide), which is made by catalyzed air-oxidation of ethylene (cf. Section 5.05.4.2.2(f)), and methyloxirane (propylene oxide), which is made by /3-elimination of hydrogen chloride from propene-derived 1-chloro-2-propanol (cf. Section 5.05.4.2.1) and by epoxidation of propene with 1-phenylethyl hydroperoxide cf. Section 5.05.4.2.2(f)) (79MI50501). 

Epoxidation with hydrogen peroxide has also been tried. The epoxidation reaction is catalyzed with compounds of As, Mo, and B, which are claimed to produce propylene oxide in high yield ... 

Allyl alcohol is produced by the catalytic isomerization of propylene oxide at approximately 280°C. The reaction is catalyzed with lithium phosphate. A selectivity around 98% could be obtained at a propylene oxide conversion around 25% ... 

Propylene glycol, glycolysis of polyurethanes with, 572 Propylene oxide (PO), glycolysis of polyurethanes with, 572-573 Propylene oxide (PO) polyols, 211, 223 Proton exchange membrane fuel cells (PEMFCs), 272-273 Proton NMR integrations, 386. See also H NMR spectroscopy Protonic acids, reactions catalyzed by, 67-68... 

Co/Zn double metal cyanide catalyzed ring-opening polymerization of propylene oxide effect of cocataiysts on polymerization behavior... 

Cationic complexes, such as 55 and 56, catalyze the polymerization of propylene oxide, cyclohexene oxide, and of e-caprolactone with substantially higher activities than neutral zinc complexes. 

The reaction of olefin epoxidation by peracids was discovered by Prilezhaev [235]. The first observation concerning catalytic olefin epoxidation was made in 1950 by Hawkins [236]. He discovered oxide formation from cyclohexene and 1-octane during the decomposition of cumyl hydroperoxide in the medium of these hydrocarbons in the presence of vanadium pentaoxide. From 1963 to 1965, the Halcon Co. developed and patented the process of preparation of propylene oxide and styrene from propylene and ethylbenzene in which the key stage is the catalytic epoxidation of propylene by ethylbenzene hydroperoxide [237,238]. In 1965, Indictor and Brill [239] published studies on the epoxidation of several olefins by 1,1-dimethylethyl hydroperoxide catalyzed by acetylacetonates of several metals. They observed the high yield of oxide (close to 100% with respect to hydroperoxide) for catalysis by molybdenum, vanadium, and chromium acetylacetonates. The low yield of oxide (15-28%) was observed in the case of catalysis by manganese, cobalt, iron, and copper acetylacetonates. The further studies showed that molybdenum, vanadium, and... 

Further studies demonstrated the influence of the double-bond substitution on both the reactivity and the stereoselectivity of the reaction [78-81]. Tamaru and co-workers reported then that using the same PdCl2/CuCl2/MeOH system on butenol derivatives, with the double bond in either the terminal or an internal position, furnished selectively y-butyrol-actones. This dicarbonylation process most probably includes (i) a lactoniza-tion step and (ii) a methoxycarbonylation step, as displayed in Scheme 11 in which we clarify some intermediate steps on a representative example [82, 83]. The use of propylene oxide as an additive promotes this Pd-catalyzed dicarbonylation by playing the role of an HC1 quencher to maintain neutral conditions. 

R. Meiers, U. Dingerdissen, and W. F. Holderich, Synthesis of propylene oxide from propylene, oxygen and hydrogen catalyzed by palladium—platinum-containing titanium silicate, J. Catal. 176, 376-386(1998). 

Poly(ethylene oxide) polymers and poly(ethylene oxide/propylene oxide) copolymers with iminodipropionitrile (139) or iminodiacetonitrile end groups were used as ligands in the palladium-catalyzed oxidation of higher olefins (1-octene to 1-hexadecene) at 50-70 °C with atmospheric air or 1-3 bar O2. In an ethanol/water mixture 88 % yield of 2-hexanone and 92 % yield of 2-hexadecanone was obtained in 4 and 2 h, respectively, with a... 

Olefin epoxidation is an important industrial domain. The general approach of SOMC in this large area was to understand better the elementary steps of this reaction catalyzed by silica-supported titanium complexes, to identify precisely reaction intermediates and to explain catalyst deachvahon and titanium lixiviation that take place in the industrial Shell SMPO (styrene monomer propylene oxide) process [73]. (=SiO) Ti(OCap)4 (OCap=OR, OSiRs, OR R = hydrocarbyl) supported on MCM-41 have been evaluated as catalysts for 1-octene epoxidation by tert-butyl hydroperoxide (TBHP). Initial activity, selechvity and chemical evolution have been followed. In all cases the major product is 1,2-epoxyoctane, the diol corresponding to hydrolysis never being detected. 

Wang JT, Zhu Q, Lu XL, Meng YZ (1995) ZnGA-MMT catalyzed the copolymerization of carbon dioxide with propylene oxide. Eur Polym J 41 1108-1114... 

Although no direct evidence was available, Ben-Taarit et al. advanced a tentative mechanism for propylene oxidation [2]. As only heterogeneous or mixed oxides catalyze the formation of acrolein, the behavior of Cu+ y zeolite is similar to the heterogeneous case. On the contrary, on Rh +Y, acetone was selectively produced [2]. This is now in line with the behavior of Rh salts in... 

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