Of propan-1,3-diol

Unsaturated substituents of dioxolanes 36-38 and dioxanes 39-41 are prone to prototropic isomerization under the reaction conditions. According to IR spectroscopy, the isomer ratio in the reaction mixture depends on the temperature and duration of the experiment. However, in all cases, isomers with terminal acetylenic (36, 39) or allenic (37, 40) groups prevail. An attempt to displace the equilibrium toward the formation of disubstituted acetylene 41 by carrying out the reaction at a higher temperature (140°C) was unsuccessful From the reaction mixture, the diacetal of acetoacetaldehyde 42, formed via addition of propane-1,3-diol to unsaturated substituents of 1,3-dioxanes 39-41, was isolated (74ZOR953). 

A palladium phosphine complex [e.g., BCPE = l,2-bis(l,5-cyclooctylenephos-phino)ethane] was also reported to produce propanediols and n-propanol from glycerol at 443 K under 6 MPa CO/H2 atmosphere in acidic conditions, n-Propanol is the dominant product, while a slight preference for the formation of propane-1,3-diol is seen in the diol fraction. Reactions were performed at different temperatures in the range 413-448 K. Since acrolein was monitored at high temperature, a reaction network was proposed following a sequential dehydration/hydrogenation pathway [20]. 

The formation of intermediate fluorosulfites also appears to be characteristic of the reactions of 1,3- and 1.4-diols however, these compounds were not isolated. The reaction of propane-1,3-diol, butane-1,3-diol and butane-1,4-diol with sulfur tetrafluoride gives, respectively, 3-fluoro-propan-l-ol, 3-fluorobutan-l-ol and 4-fluorobutan-l-ol.59... 

Alkylene CCs have been prepared through the transesterification of appropriate glycols with dialkyl carbonates (usually diethyl or dimethyl carbonate) in the presence of a suitable catalyst. One of the first such examples was the synthesis of six-membered CCs by the transesterification of propane-1,3-diols with DEC catalyzed by sodium ethanolate (Equation 7.31) [289], The reaction was carried out at temperatures between 293 and 333 K, and a conversion yield of 40% was obtained. 

A similar method has been reported by Albertsson et al. [290], in which equimolar amounts of propane-1,3-diol and DEC were used, with stannous 2-ethylhexanoate as the transesterification catalyst, affording a yield of 53%. 

Other examples [291, 292] have included the use of propane-1,3-diols which had been differently substituted and treated with DEC in the presence of catalytic amounts of sodium methoxide. Then, depending on the reaction conditions, either polycarbonates or CCs were produced in high yield. 

Diodopropane - from 40 g (38 ml, 0.525 mol) of propane-1,3-diol (trimethylene glycol). Proceed as for iodocyclohexane stop heating as soon as all the iodine has been added. (B.p. 88-89 °C/6 mmHg). 

Dibromopropane (trimethylene dibromide). In a 1-litre round-bottomed flask place 500 g (338 ml) of 48 per cent hydrobromic acid and add 150 g (82 ml) of concentrated sulphuric acid in portions, with shaking. Then add 91 g of propane-1,3-diol (b.p. 210-215 °C), followed by 240g (130.5ml) of concentrated sulphuric acid slowly and with shaking. Attach a reflux condenser to the flask and reflux the mixture for 3-4 hours. Arrange for downward distillation and distil, using a wire gauze, until no more oily drops pass over (30-40 minutes). Purify the 1,3-dibromopropane as detailed for butyl bromide above. About 220 g (91%) of the pure dibromide, b.p. 162-165 °C, are obtained. 

In the absence of silver ions the oxidation is extremely slow. The reaction is first-order with respect to both peroxodisulphate and silver ions, and the rate is independent of the pinacol concentration. Menghani and Bakore suggest a chain mechanism involving sulphate radical-ions and silver(II) ions. The same workers found the same type of rate equation for the oxidations of propane-1,3-diol and butane-l,3-diol, and propose the same mechanism. 

By using palladium on carbon, from previous studies on C3-diol oxidation, poor selectivity can be expected in the case of propane-1,2-diol [12] and good selectivity in the case of propane-1,3-diol (86% of 3-hydroxy-propanoate) [6a],... 

The T1(C104)3 oxidation of (MeCO)2CH2 and PhCOCH2COMe in acid is zero-order in oxidant and first-order each in substrate and HCIO4. A mechanism involving rate-determining enolization has been proposed. The mode of electron transfer in ruthenium(ni) chloride-catalysed oxidation of propane-1,3-diol by thallium(III) is explained by hydride ion abstraction. ... 

The oxidation of DL-methionine by sodium iV-chlorotoluene-p-sulfonamide (CAT) in alkaline medium catalysed by OSO4 shows a first-order dependence each on CAT and methionine, an inverse fl actional-order dependence on HO , and a fractional-order dependance on 0s04. " The oxidation of mono-, di-, and tri-ethanolamine (MEA, DEA, and TEA, respectively) by CAT " and sodium A-bromotoluenesulfonamide (bromamine-T, BAT) " in alkaline buffer is first order in oxidant and fractional order each in substrate and HO. The oxidation rate increased in the order di- > tri- > mono- and suitable mechanisms consistent with the kinetic data have been proposed. Osmium(Vni)-catalysed oxidation of propane-1,3-diol by CAT in alkaline medium proceeds via hydride-ion abstraction fi om the a-carbon of the diol. " ... 

The synthesis of six-membered cyclic carbonates by transesterification of propane-1,3-diols (PPDs) with diethyl carbonate catalyzed with sodium ethanolate described by Carothers and Van Natta gives a yield of 40%. Also Pohoryles and... 

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