Diallyl thermal reaction

Thermal Reaction of Propylene. Thermal reaction of propylene has been studied extensively. Laidler and Wojciechowski (16) reported that main products were ethylene, methane, and hydrogen and that minor ones were ethane, propane, butenes, cyclopentadiene, cyclohexadiene, benzene, toluene, and diallyl at temperatures from 580° to 640°C pressures from 40 to 400 mm Hg in a static system. No allene was detected, which is in contrast to the results obtained at higher temperatures by Szwarc (21) and by Sakakibara (19). Reaction order was determined as 3/2, and the A-factor and activation energy were reported as 1013 34 ml1/2 mole"1/2 sec"1 and 56.7 kcal/mole, respectively. Kallend et ah (9) carried out a detailed analysis of the reaction product at 555° -— 640°C and pressures 7 300 mm Hg. The main C6 compounds present were 1,3-and 1,4-hexadiene. Methylcyclohexene and cyclohexadienes were not found. 

Allyl radicals were tested as materials or substances that cause cyclization with olefins. 1,5-Hexadiene (diallyl) and diallyl oxalate (DAO) were used as the source materials for allyl radicals. These compounds were subjected to the thermal reaction in the presence of ethylene, which resulted in a rapid formation of five-membered cyclic compounds. The role of allyl radical for the formation of aromatics in pyrolysis reaction is however still... 

Thermal Reaction of Diallyl. Overall mass balances for the pyrolysis experiments of diallyl in excess nitrogen generally were within 96- 99 %. It was confirmed that the effect of the quartz surface on the reaction was negligible under the present conditions. The conversion of the reactant has been defined as the ratio of the sum of the peak areas of products to that of all peak areas of the gas chromatogram. 

From Figure 1, it is clear that the primary products of the thermal reaction of diallyl are ethylene, propylene, 1-butene, butadiene, 1-pentene, cyclopentene, cyclopentadiene, and 1,3,5-hexatriene, and the secondary products are 1,3-cyclohexadiene and benzene. Trace amounts of methane, propane, and 1,4-pentadiene were also found in some experiments. No hydrogen was detected by a nitrogen carrier gas chromatograph with MS 5A column. The formation of C 2 compounds was noticed at low temperatures. A small amount of liquid product was found in the separator tube after 50 or more experimental runs. The average molecular weight of the liquid product was 428 based on the method of Hill (15). 

By extrapolating the curves in Figure 1 to zero conversion, the molar ratios of formation of individual products at the initial stage of the reaction were approximated as listed in Table III, in which the amount of ethylene was taken as unity. From Table III and Figure 1, the radical chain mechanism of the thermal reaction of diallyl is proposed as follows. 

Thermal Reaction of Diallyl in Excess Ethylene. It was shown in the preceeding section that diallyl decomposed in nitrogen at... 

C forming allyl radicals as the initial step of the reaction. At the same time, it was reported previously ( ) that a thermal reaction of ethylene itself scarcely proceeded below 700 C. Experiments on pyrolysis of diallyl in excess ethylene were conducted at temperatures between 580 and 700 C, and at very low concentrations of diallyl, between 0.2 and 0.7 mol %, so as to cause exclusively the expected reaction of allyl radical with ethylene. 

Thermal Reaction of DAO in Excess Ethylene. To get better knowledge about the formation of cyclopentene and 1-pentene, DAO was employed as another source material for allyl radicals. In the case of the pyrolysis of DAO in excess ethylene, the reaction temperature was considerably lowered, and a large amount of diallyl was produced, accompanied with cyclopentene, 1-pentene, propylene, 1-butene, butadiene and cyclopentadiene. All of these except diallyl were the same main products as obtained in the pyrolysis of diallyl in excess ethylene. In other words, the same mechanism regulate both the reactions of DAO and those of diallyl in the presence of ethylene. 

A summary of rate data is given for the systematic study of the formation of cyclic compounds during thermal reactions of olefins or of olefins with butadiene. As a next step in order to investigate cyclization at pyrolysis conditions, the reactions of allyl radicals with olefins were studied kinetically. 1,5-Hexa-diene (diallyl) and diallyl oxalate (DAO) were employed as source... 

An important property of metal-bound phosphole ligands is their ability to undergo additional reactions not possible in the noncomplexed form. This is nicely illustrated by the thermally induced reactions of the palladium(ll) complex of 1-phenyl-3,4-dimethylphosphole 341 <1996IC1486>. Heating complex 341 at 145 °C in solution or at 140 °C in the solid state led to the formation of a mixed 7-phosphanorbornene-phosphole complex 343 (Scheme 114). These intramolecular [4-1-2] cycloaddition reactions are believed to proceed via the initial formation of a diallyl 1,4-biradical TS 342. Further examples of this type of reaction may be found in Section 3.15.12.1.1. 

The reactions of allyliron tricarbonyl halides with donor molecules were studied. Triphenylphosphine substituted only one carbonyl, that trans-oriented with respect to the halogen of the form (XIX) [432). The phosphine derivatives of (XX) were not isolated as pure compounds. The complexes were decomposed entirely by dimethyl sulfoxide, giving [(0113)280] jFeX2 [435). Thermal decomposition of C3H5Fe(CO)3X depended on the medium and gave either diallyl, or diallyl ketone, together with propene, allyl ether, Fe(CO)5, and FeX2 [436). 

Allylation of the 2,3-Wittig products (167) leads to diallylic ethers (171) in which one of the allylic double bonds is part of a 1,5-diene system. These ethers undergo 3,3-oxy-Cope rearrangement to afford vinyl allyl ethers (170), which rearrange in situ by a 3,3-Claisen process to yield the ( )-dienals (169). Some typical results are summarized in Table 14. The cyclopentanols (175) were shown to arise from aldehydes (169) by an intramolecular thermal ene reaction. ... 

As 4-atom fragments, allylamines are often used for the synthesis of 1,2-azaborolidines, 1,2-azoniaboratolidines, 1,2-azaboroles, and 1,2-azoniaboratoles. 1,2-Azaborolidines are generally formed if borane-amine adducts are thermally burdened in the presence of alkyl-, allyl-, and diallyl amines. These reactions can also be described as hydroborations of diallyl compounds (Equations (22) and (23)) <70ZOB1528,76IOC2803>. 

James and Troughton ( ) obtained ethylene and 1,3,5-hexatriene as the primary products in their study on the reaction of diallyl with the ethyl radical at 134- 175 C. Furthermore, they obtained 1,3-cyclohexadiene as a successive product. Recently Orchard and Thrush (19) reported the thermal isomerization of 1,3,5-hexatriene to 1,3-cyclohexadiene at ca. 400 C and the consecutive formation of benzene at ca. 550 C. In the present work, 1,3-cyclohexadiene (reaction 17) and benzene (reaction 18) were obtained as the secondary products. The hydrogen atom produced in reactions 12,... 

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