Polymerization Of Benzyl Alcohol Research Articles

New reactor in jet spouted bed regime for catalytic polymerizations

The hydrodynamic features, suitable for catalytic polymerization in the gaseous phase, of a new reactor in the jet spouting regime have been studied. This regime is reached by expansion of conical spouted beds. The application of the jet spouted bed as a reactor in catalytic polymerizations implies the treatment of sticky solids with a wide particle size distribution, even of catalyst particles of reduced size (less than 1 mm diameter), which are not habitually treated in conventional spouted beds. The jet spouted bed has a high stability and reduced segregation together with a great capacity for continuous operation of the solids. In a pilot-plant scale unit, the following original aspects of the gas-solid contact have been studied: the design factors for stable operation (contactor angle, ratio between the inlet diameter and the base diameter of the contactor, ratio between the inlet diameter and the particle diameter); the hydrodynamics (correlations for the calculation of the minimum velocity, of the stable operation pressure drop and of the maximum pressure drop); the proposal of a disperse plug flow model for the gas in the reactor, and the subsequent calculation of the dispersion coefficient. The behaviour of the jet spouted bed as a reactor in the polymerization of benzyl alcohol has been studied in an automated laboratory unit where the effect of the residence time of the catalyst and the alcohol concentration in the feed have been analysed.

New reactor in jet spouted bed regime for catalytic polymerizations

The hydrodynamic features, suitable for catalytic polymerization in the gaseous phase, of a new reactor in the jet spouting regime have been studied. This regime is reached by expansion of conical spouted beds. The application of the jet spouted bed as a reactor in catalytic polymerizations implies the treatment of sticky solids with a wide particle size distribution, even of catalyst particles of reduced size (less than 1 mm diameter), which are not habitually treated in conventional spouted beds. The jet spouted bed has a high stability and reduced segregation together with a great capacity for continuous operation of the solids. In a pilot-plant scale unit, the following original aspects of the gas-solid contact have been studied: the design factors for stable operation (contactor angle, ratio between the inlet diameter and the base diameter of the contactor, ratio between the inlet diameter and the particle diameter); the hydrodynamics (correlations for the calculation of the minimum velocity, of the stable operation pressure drop and of the maximum pressure drop); the proposal of a disperse plug flow model for the gas in the reactor, and the subsequent calculation of the dispersion coefficient. The behaviour of the jet spouted bed as a reactor in the polymerization of benzyl alcohol has been studied in an automated laboratory unit where the effect of the residence time of the catalyst and the alcohol concentration in the feed have been analysed.

Polymerization of benzyl alcohol in anhydrous hydrogen fluoride: an efficient synthesis of poly(phenylenemethylene)

It has been shown that benzyl alcohol is transformed rapidly and almost quantitatively into poly(phenylenemethylene) by adding it to anhydrous hydrogen fluoride at 16°C; the product is the so-called ‘soluble poly(phenylenemethylene)’ with a degree of polymerization of ≈20. p-Methylbenzyl alcohol has also been oligomerized by a similar procedure. The potential for adaption to industrial-scale use is highlighted.

Catalysis by heteropolyacid—VI. Asymmetric polycondensation of benzyl alcohol to optically active polybenzyl initiated by brucine-induced chiral diphosphooctadecamolybdic acid

Diphosphooctadecamolybdic acid, the so-called Dawson-type heteropolyacid with a formula of H 6[P 2Mo 18O 62], shows a Pfeiffer effect due to the equilibrium shift to one enantiomer in the presence of l-brucine sulphate in benzyl alcohol solution. Heating the homogeneous system caused polymerization of non-chiral benzyl alcohol to chiral polybenzyl. This reveals that the structure of the heteropolyanion-moiety plays an important role in the polymerization of benzyl alcohol.

Polymerization of benzyl alcohol and its derived compounds with an ion exchange resin

Benzyl alcohol, benzyl chloride and dibenzyl ether polymerize in certain conditions in the presence of ion exchange resins in the H+ form to give a polymer of the general formula (C6H4CH2)n. Independently of the reactant, this result allows to establish reaction mechanism based solely on the acid-base equilibrium in the Bronsted or Lewis meaning and independently of the catalyst type: sulfuric acid, stannic chloride or ion exchange resin.