Theoretical Study of Thermal Dehydrochlorination of Poly(vinyl chloride) Initiated by Tertiary Chlorine Groupings

1995 ◽  
Vol 60 (8) ◽  
pp. 1303-1309 ◽  
Author(s):  
Jaroslav Burda ◽  
Rudolf Lukáš

Thermal dehydrochlorination of syndiotactic poly(vinyl chloride) sequences initiated by structural defects possessing chlorine atoms bound on tertiary carbon atoms (branched structures) was theoretically studied on the low-molecular-weight models using the semiempirical quantum chemical methods MNDO and AM1. The results are compared with those obtained previously by studying the dehydrochlorination in syndiotactic sequences without defects. It was found that elimination of the first HCl molecule is much easier in the branched structure. However, this effect fast decreases with dehydrochlorination continuing along the chain due to its distinct localization in the closest vicinity of tertiary carbon atom. A detailed evaluation of possible radical and ionic intermediates revealed that for ionic mechanism of dehydrochlorination the effect of branching is perceptible slightly longer.

1992 ◽  
Vol 57 (1) ◽  
pp. 93-106 ◽  
Author(s):  
Jaroslav Burda ◽  
Rudolf Lukáš

The thermal dehydrochlorination of syndiotactic poly(vinyl chloride) sequences has been studied theoretically on low-molecular weight models ranging from vinyl chloride dimer to pentamer using the semiempirical quantum chemical MNDO method. Parameters obtained with saturated systems and their change caused by the proceeding elimination of hydrogen chloride accompanied by the formation of the corresponding unsaturated structures are discussed with respect to the repeated chloroallyl or α-chloropolyene activation of the dehydrochlorination process. The study of the assumed radical and ionic intermediates is used in discussing the reaction mechanism of dehydrochlorination, and the radical or ionic mechanism is supposed to be operative depending on the reaction conditions.


2014 ◽  
Vol 20 (2) ◽  
pp. 65-71 ◽  
Author(s):  
Oscar Yesid Suárez Palacios ◽  
Paulo César Narváez Rincón ◽  
Jean-Pierre Corriou ◽  
Mauricio Camargo Pardo ◽  
Christian Fonteix

2007 ◽  
Vol 16 (1) ◽  
pp. 495-501 ◽  
Author(s):  
A. Caraculacu ◽  
O. Wichterle ◽  
B. Schneider

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