Telomerization Of Propylene Research Articles

Theoretical investigation of the 1,3-migration of hydrogen in the telomerization of ethylene and propylene with methanol

Semiempirical quantum-chemical calculations by the MINDO/3 method have been carried out with complete optimization of the geometry of all the radicals in the molecules which take part in the telomerization of ethylene and propylene with methanol. For each of the telomerization processes the transition states have been determined for three competing reactions: 1,3-H-migration, chain transfer, and chain growth. It is concluded by a comparison of the heat effects and the potential barriers that 1,3-H-migration is possible for the telomerization of propylene, but improbable for the telomerization of ethylene.

Chain termination in the telomerization of propylene with CCl4 initiated by tert-butyl peroxide and the W(CO)6-PPh3 system

1. The use of PPh3 as a coinitiator in the telomerization of propylene with CCl4 leads to a significant increase in the yield of allylic termination products relative to initiation with TBP or W(CO)6. 2. Independently of the course of the telomerization, PPh3 reacts with propylene and CCI4, with the formation of CHCl3, i-PrCl, and n-PrCl.

Quantum chemical aspects of the 1,3-hydrogen migration in radical telomerization

1. The MINDO/3 method was used to study three model competing reactions of the radicals formed upon the telomerization of ethylene and propylene: 1,3-hydrogen migration, chain propagation, and chain transfer. 2. 1,3-Hydrogen migration is more likely in the telomerization of propylene than in the telomerization of ethylene, in which the activation energy is twice that of the two competing reactions.

Stereodirectivity in the radical telomerization of propylene with CCl4, initiated by metal carbonyl systems

1. 13C NMR and capillary GLC have been used to show that in the telomerization of propylene with CCl4, initiated by TBP, Cr(CO)6, Fe(CO)5+DMF, or W(CO)6+PPh3, the racemic diastereoisomeric forms of the telomers CCl3[CH2CH(CH3)]n Cl (n=2,3) are formed in approximately equal amounts. 2. The similarity in the stereodirectivity of the telomerization, whether initiated by TBP or by Cr(CO)6, Fe(CO)5+DMF, or W(CO)6+PPh3, indicates that in the last three cases the reaction proceeds by a stepwise free-radical mechanism.

Chromatographic-mass spectrometric study of the products of radical telomerization of propylene with CCl4

1. In the radical telomerization of propylene with CCl4, isomeric telomers with abnormal insertion of the monomeric units are formed in small quantities together with telomers with a normal structure. 2. The relative concentration of the abnormal telomers increases with an increase in the length of the chain of the telomer.

Step-by-step telomerization of propylene and 1-hexene by carbon tetrabromide

1. The reaction of CBr4 with propylene and 1-hexene can be carried out depending on the method of initiation, as an addition reaction with tne formation of CBr3CH2CHBrCH3 and CBr3CH2-CHBr(CH2)3Cu3 or as a step-by-step telomerization with the formation of CBr2(CH2CHBrCH3)2 and CBr2(CH2CHBrCH2CH2CH2CH3)2. 2. The addition of compounds containing a Cur3 group to unsaturated compounds proceeded by cleavage of tne C-Br bond during initiation by Fe(CO)5+DMFA.

Telomerization of propylene by bromoform

1. The telomerization of propylene by bromoform leads to the formation of telomer homologs with the general formula CHBr2(CH2CHCH3)nBr. Telomers with n=1 and 2 were isolated. The first individual chain transfer constant (C1) in this telomerization is about 150. 2. In addition of bromoform to propylene proceeds largely at theα-carbon atom (>90%) and to a slight extent at theβ-carbon atom of the double bond. This leads to the formation of adducts CHBr2CH2CHBrCH3 and CHBr2CH(CH3)CH2Br.

Relative kinetics for the telomerization of propylene by the methyl esters of chloroacetic and trichloroacetic acids and CCl4 induced by Mn2(CO)10 systems

Individual chain transfer constants found for the telomerization of propylene with methyl chloroacetate, methyl trichloroacetate, and CC14 initiated by Mn2(CO)10 are similar to the values obtained in the case of peroxide initiation.

Partial chain-transfer constants in telomerization of propylene with CCl4, initiated by molybdenum and tungsten hexacarbonyls

1. The first and second chain-transfer constants in the telomerization of propylene with CCl4, initiated by Mo (CO)6 at 120° and by W(CO)6 at 140°, were determined. 2. A coinciding of the partial chain-transfer constants and a retention of the same stereodirectivity of the reaction when it is initiated by either peroxides or the molybdenum and tungsten hexacarbonyls indicate the free-radical mechanism of the telomerization in the presence of Mo(CO)6 and W(CO)6.

Relative kinetics in the telomerization of propylene with CCl4 initiated by coordination initiators based on Cr(CO)6

1. The first and second chain-transfer constants have been determined in the telomerization of propylene with CCl4 initiated by Cr(CO)6 in the presence of HMPA, DMFA, CH3CN, and CH3OH at 120‡C. 2. The partial chain-transfer constants for telomerization initiated by benzoyl peroxide, Cr(CO)6, and Cr(CO)6 in combination with nucleophilic additives coincide, from which itfollows that the additives studied do not affect chain growth and transfer stages.

1,5- and 1,9-migration of hydrogen during telomerization of propylene with dimethyl acetal

1. The telomerization of propylene with dimethyl acetal leads to the formation of two series of telomers, and specifically acetals and acetates. 2. The formation of the acetates is due to rearrangement of the growing radicals with a 1,5- and 1,9-migration of hydrogen. The transition from ethylene to propylene leads to a substantial increase in the degree of 1,9-migration of hydrogen.

Effect of temperature variation on course of telomerization of propylene with methyl chloroacetate

1. A decrease in the telomerization temperature of propylene with methyl chloroacetate from 150 to 25° leads to a decrease in the degree of rearrangement of the.(CH(CH3)nCHClCO2CH3 radicals with a 1,3-(n=1) and 1,5-(n=2) migration of hydrogen. 2. The rearrangement of the radicals with a 1,3-migration of hydrogen during telomerization is much more sensitive to variation in the reaction temperature than in the case of the 1,5-transition of hydrogen.

Telomerization of propylene with methyl acetate

1. The telomerization of propylene with methyl acetate is accompanied by rearrangement of the first and second growing radicals, with the 1,3- and 1,5-migration of hydrogen. 2. In the telogen series RCH2CO2CH3 (R= CH3, Cl, H), when reaction is with propylene, rearrangement with the 1,3-migration of hydrogen is least in the case of methyl acetate (R =H), which indicates that the R substituent has an important effect on the course of the rearrangement.

Telomerization of propylene with methyl dichloroacetate

Telomerization of propylene with methyl dichloroacetate

Telomerization of propylene with methyl trichloroacetate

1. The telomerization of propylene with methyl trichloroacetate leads to the formation of the telomers where n = 1–3. 2. The partial chain transfer constants in the system propylene-methyl trichloroacetate are one order of magnitude higher than in the reaction of methyl trichloroacetate with ethylene.

Telomerization of propylene with ethyl formate

Telomerization of propylene with ethyl formate

Telomerization of propylene with carboxylic acids

1. The telomerization of propylene with isobutyric and propionic acids were studied. 2. The partial chain transfer constants in the telomerization of propylene with isobutyric acid are substantially higher than in the reaction of carboxylic acids with ethylene. 3. The telomerization of propylene with propionic acid goes with rearrangement of the radicals, which includes a 1,3-migration of the H atom.

Telomerization of propylene with methyl propionate

Rearrangement of the radicals, with a 1,3-migration of the H atom, occurs during the telomerization of propylene with methyl propionate.

Rearrangement of radicals in telomerization of propylene with methyl chloroacetate

1. The telomerization of propylene with methyl chloroacetate is accompanied by rearrangement of the radicals. Data are given that testify to the fact that, along with 1,3-migration of the H atom, rearrangement of the radicals with a 1,5-migration of the H atom takes place. 2. It was postulated that rearrangement of the radicals with a 1,6-migration of the H atom is present in the given system.

Some characteristics of alkylation of toluene with propylene in presence of Ziegler catalyst

1. The alkylation of toluene in the presence of the complex organometallic catalyst: TiCl4 + Al (i-C4H9)2Cl+CH3OH is the consequence of the cationic telomerization of propylene. 2. A method was proposed for determining the mean degree of alkylation and the structure of the reaction products was studied.