الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
Most drugs consist of two optical isomers, and pharmaceutical companies face two main problems. First, if one of the two isomers is active to treat the disease and the other is inactive, so it will be a waste. Second, if both of the two isomers are active so one of them will treat the disease, however the other will cause side effects resulting in health problems for the patient, so scientists focus on solution of this problem to purify the drug and improve its industry.
In this study, a novel polymer had been synthesized to be used as a catalyst for the production of optically active polymer which can be used in the separation of enantiomers thus purification of medicines.
A novel chiral phenylacetylene monomer with chiral phenylethylamine residue ((R)-PEAPA) was synthesized. Using a rhodium initiator this monomer was polymerized at room temperature to give an optically-active helical homopolymer (poly(PEAPA)) with molecular weight (Mw) of around 2.4 x106. Poly(PEAPA) was used as a polymeric catalyst for the helix-sense-selective polymerization of achiral monomer (4-dodecyloxy-3,5-bis(hydroxymethyl) phenylacetylene), DHPA. The polymeric catalyst could be recycled with nearly no loss of its activity.
The kinetics and mechanism of polymerization of the achiral monomer DHPA was investigated, using the novel polymeric catalyst. The results showed that using this polymeric catalyst, an optically-active helical polymer had been produced. However, in case of the non-catalytic polymerization, the polymer obtained was produced without helical structure which in turn had no optical activity. The reaction was followed within a temperature range of 5 to 25oC. The kinetic data obtained were correlated well with a second order kinetic approach.
Using the Arrhenius and Eyring equations, the thermodynamic parameters were calculated. The values of the activation energy (Ea), the change in enthalpy (∆H), and the change in entropy (∆S), for catalytic and non-catalytic polymerizations were found to be (-29.08 kJ/mol), (-31.51 kJ/mol), and (-0.28 kJ/mol), and (+36.77 kJ/mol), (+34.38 kJ/mol), and (-0.27 kJ/mol), respectively. Additionally, the change in the free energy of activation (∆G) has its lowest value (46.33 kJ/mol) for the catalytic polymerization at 5°C. This indicated the lowest energy barrier and corresponded to the highest reaction rate, (k = 0.15 L/(mol.s)) compared with the highest free energy (115.44 kJ/mol) and the lowest reaction rate (k = 0.02 L/(mol.s)) for the non-catalytic polymerization. The values of the thermodynamic parameters indicated that the reaction mechanism could be considered as a chain reaction stabilized through a catalytic route with diffusion controlled and associative mechanism.
The new monomer ((R)-PEAPA) was copolymerized with different ratios of an achiral trimethylsilylphenylacetylene (SPA) at room temperature to give an optically-active helical copolymers with molecular weights (Mw) of around 2-5x105. It was found that copoly((R)-PEAPA/SPA) had a one-handed helical structure; a fact indicating that ((R)-PEAPA) was suitable for asymmetric-induced copolymerization of SPA.
A comparison between the prepared copolymer (copoly ((R)-PEAPA/SPA)) with the homopolymer (poly(PEAPA)) to determine their effectiveness as catalysts for the helix-sense-selective polymerization of DHPA. It had been proved that the homopolymer had a better efficiency and was easier in the separation than the copolymer.
The design procedures of batch polymerization reactor have been investigated and the design data were based on kinetic data.