The heck reactions of aryl bromides in ionic liquids medium of n-butyl-n-methylpyrrolidinium trifluoromethanesulfonate

The application of the ionic liquids in the palladium catalyzed Heck reactions have been reported extensively, however, without proper evidence addressing the role of ionic liquids in the catalytic process. In this thesis, a new series of N-alkyl-Nmethylpyrrolidinium trifluoromethanesulfonate salts...

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Main Author:	Ahmad Tajudin, Mohamad Hafiz
Format:	Thesis
Language:	English
Published:	2006
Subjects:	Q Science (General) QD Chemistry
Online Access:	http://eprints.utm.my/id/eprint/2077/1/MohamadHafizAhmadTajudinMFS2006.pdf
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spelling	my-utm-ep.20772018-06-13T07:05:19Z The heck reactions of aryl bromides in ionic liquids medium of n-butyl-n-methylpyrrolidinium trifluoromethanesulfonate 2006-02 Ahmad Tajudin, Mohamad Hafiz Q Science (General) QD Chemistry The application of the ionic liquids in the palladium catalyzed Heck reactions have been reported extensively, however, without proper evidence addressing the role of ionic liquids in the catalytic process. In this thesis, a new series of N-alkyl-Nmethylpyrrolidinium trifluoromethanesulfonate salts (46-52) have been synthesized to study their potential as the alternative solvents for the Heck reaction, instead of using conventional molecular solvents. These salts were synthesized through quaternization reaction between N-methylpyrrolidine (38) with several alkyl iodides, followed by metathesis reaction with silver trifluoromethanesulfonate, to give the desired products (46-52) (yield: 72-96%) with melting points ranging from room temperature to 300Â°C. All the salts obtained were characterized by using 1H and 13CNMR spectroscopies, CHN elemental analysis, melting point, density and molar conductivity. The effects of alkyl chains towards the melting points and molar conductivities of these salts (46-52) have been investigated. The N-butyl-Nmethylpyrrolidinium trifluoromethanesulfonate, [Bmplim]CF3SO3 (49), has been chosen as the solvent in the Heck reactions between methyl acrylate (61) and several types of aryl bromides (56-60) to give Heck adducts (62-66) with satisfactory yield between 37 to 97%. Parameters such as the types of bases, the amount of Pd catalyst loadings and the reaction temperatures were also studied in order to optimize the percentage conversion of respective Heck adducts (62-66). Results show that, the optimum condition to enhance the percentage conversion for this catalytic system is by using Et3N as base, Pd catalysts loading at 1.5mmol% and reaction temperature at 120Â°C, to achieve the calculated TONs of ~6667. With these conditions, the Heck adducts of reactive aryl bromides; 4-bromonitrobenzene (56), 4-bromoacetophenone (57) and bromobenzene (58) have achieved an extremely high percentage conversion (~100%). As for the unreactive aryl bromides; 4-bromoanisole (59) and 4- bromoaniline (60), the addition of PPh3 was proved to be useful; however, leads to contamination from the by-product which results to problematical separation of the desired products (62-66). The ionic liquid of [Bmplim]CF3SO3 (49), can be recycled up to three runs, without showing any distinct losses in its activities 2006-02 Thesis http://eprints.utm.my/id/eprint/2077/ http://eprints.utm.my/id/eprint/2077/1/MohamadHafizAhmadTajudinMFS2006.pdf application/pdf en public masters Universiti Teknologi Malaysia, Faculty of Science Faculty of Science
institution	Universiti Teknologi Malaysia
collection	UTM Institutional Repository
language	English
topic	Q Science (General) QD Chemistry
spellingShingle	Q Science (General) QD Chemistry Ahmad Tajudin, Mohamad Hafiz The heck reactions of aryl bromides in ionic liquids medium of n-butyl-n-methylpyrrolidinium trifluoromethanesulfonate
description	The application of the ionic liquids in the palladium catalyzed Heck reactions have been reported extensively, however, without proper evidence addressing the role of ionic liquids in the catalytic process. In this thesis, a new series of N-alkyl-Nmethylpyrrolidinium trifluoromethanesulfonate salts (46-52) have been synthesized to study their potential as the alternative solvents for the Heck reaction, instead of using conventional molecular solvents. These salts were synthesized through quaternization reaction between N-methylpyrrolidine (38) with several alkyl iodides, followed by metathesis reaction with silver trifluoromethanesulfonate, to give the desired products (46-52) (yield: 72-96%) with melting points ranging from room temperature to 300Â°C. All the salts obtained were characterized by using 1H and 13CNMR spectroscopies, CHN elemental analysis, melting point, density and molar conductivity. The effects of alkyl chains towards the melting points and molar conductivities of these salts (46-52) have been investigated. The N-butyl-Nmethylpyrrolidinium trifluoromethanesulfonate, [Bmplim]CF3SO3 (49), has been chosen as the solvent in the Heck reactions between methyl acrylate (61) and several types of aryl bromides (56-60) to give Heck adducts (62-66) with satisfactory yield between 37 to 97%. Parameters such as the types of bases, the amount of Pd catalyst loadings and the reaction temperatures were also studied in order to optimize the percentage conversion of respective Heck adducts (62-66). Results show that, the optimum condition to enhance the percentage conversion for this catalytic system is by using Et3N as base, Pd catalysts loading at 1.5mmol% and reaction temperature at 120Â°C, to achieve the calculated TONs of ~6667. With these conditions, the Heck adducts of reactive aryl bromides; 4-bromonitrobenzene (56), 4-bromoacetophenone (57) and bromobenzene (58) have achieved an extremely high percentage conversion (~100%). As for the unreactive aryl bromides; 4-bromoanisole (59) and 4- bromoaniline (60), the addition of PPh3 was proved to be useful; however, leads to contamination from the by-product which results to problematical separation of the desired products (62-66). The ionic liquid of [Bmplim]CF3SO3 (49), can be recycled up to three runs, without showing any distinct losses in its activities
format	Thesis
qualification_level	Master's degree
author	Ahmad Tajudin, Mohamad Hafiz
author_facet	Ahmad Tajudin, Mohamad Hafiz
author_sort	Ahmad Tajudin, Mohamad Hafiz
title	The heck reactions of aryl bromides in ionic liquids medium of n-butyl-n-methylpyrrolidinium trifluoromethanesulfonate
title_short	The heck reactions of aryl bromides in ionic liquids medium of n-butyl-n-methylpyrrolidinium trifluoromethanesulfonate
title_full	The heck reactions of aryl bromides in ionic liquids medium of n-butyl-n-methylpyrrolidinium trifluoromethanesulfonate
title_fullStr	The heck reactions of aryl bromides in ionic liquids medium of n-butyl-n-methylpyrrolidinium trifluoromethanesulfonate
title_full_unstemmed	The heck reactions of aryl bromides in ionic liquids medium of n-butyl-n-methylpyrrolidinium trifluoromethanesulfonate
title_sort	heck reactions of aryl bromides in ionic liquids medium of n-butyl-n-methylpyrrolidinium trifluoromethanesulfonate
granting_institution	Universiti Teknologi Malaysia, Faculty of Science
granting_department	Faculty of Science
publishDate	2006
url	http://eprints.utm.my/id/eprint/2077/1/MohamadHafizAhmadTajudinMFS2006.pdf
_version_	1747814396996878336

The heck reactions of aryl bromides in ionic liquids medium of n-butyl-n-methylpyrrolidinium trifluoromethanesulfonate

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