Sinteze i mehanizmi nukleofilne supstitucije benzilnih bromida u 50%-tnom acetonu

master's thesis

• Title (english): Syntheses and mechanisms of nucleophilic supstitution of benzyl bromides in 50% acetone
• Author: Luka Bare
• Mentor: Bernard Denegri (mentor)
• Mentor: Mirela Matić (komentor)
• Committee member: Bernard Denegri (predsjednik povjerenstva)
• Committee member: Mirela Matić (član povjerenstva)
• Committee member: Jasna Jablan (član povjerenstva)
• Granter: University of Zagreb; Faculty of Pharmacy and Biochemistry; (Department of organic chemistry); Zagreb
• Defense date and country: 2021-10-01, Croatia
• Scientific / art field, discipline and subdiscipline: NATURAL SCIENCES; Chemistry; Organic Chemistry

Abstract

Ovaj rad proučava sinteze i kinetike solvolize različito supstituiranih benzilnih bromida. Sintetizirani su 4-metilbenzil-bromid, 4-metoksibenzil-bromid, 4-(metiltio)benzil bromid, 4-tert-butilbenzil-bromid, 4-fenoksibenzil-bromid, 3,4-dimetilbenzil-bromid, 4-fenilbenzil-bromid i benzil-bromid. Identitet i čistoća spojeva potvrđena je nuklearnom magnetskom rezonancijom i tankoslojnom kromatografijom. Kinetike solvolize nije bilo moguće pratiti kod 4-metoksibenzil-bromida i benzil-bromida. Kinetička mjerenja solvolitičkih reakcija provođena su konduktometrijski u 50 %-tnoj vodenoj otopini acetona. Konstante brzina reakcija ekstrapolirane su na 25°C. Logaritmi konstanti brzina korelirani su sa σ+ vrijednostima kako bi se prikazala Hammett-Brownova korelacija. Na korelacijskom grafu dobivena su dva pravca različitih nagiba, tj. različitih reakcijskih konstanti (ρ+). Različiti nagibi pravaca ukazuju na promjenu reakcijskog mehanizma solvolize u seriji benzilnih bromida. Zaključeno je da 4-metilbenzil-bromid, 3,4-dimetilbenzil-bromid, 4-tert-butilbenzil-bromid i 4-fenilbenzil-bromid solvoliziraju putem SN2 reakcijskog mehanizma, a 4-fenoksibenzil-bromid i 4-(metiltio)benzil-bromid solvoliziraju putem SN1 reakcijskog mehanizma.

Abstract (english)

This thesis investigates syntheses and kinetics of solvolysis of differently substitued benzyl bromides. 4-methylbenzyl bromide, 4-methoxybenzyl bromide, 4-(methylthio)benzyl bromide, 4-tert-butylbenzyl-bromide, 4-phenoxybenzyl bromide, 3,4-dimethylbenzyl bromide, 4-phenylbenzyl bromide and benzyl bromide have been synthesized. Their identity and purity have been confirmed by both nuclear magnetic resonance and thin layer chromatography. The kinetics of solvolysis of 4-methoxybenzyl bromide and benzyl bromide were not measurable. The kinetics of solvolysis in 50 % aqueous acetone were studied using conductometry. Rate constants were extrapolated to 25 °C. The logarithms of rate constants were correlated with σ+ values in order to obtain Hammet-Brown's correlation. The correlation gave two lines of different slopes. The different slopes indicate a change in the reaction mechanism of solvolysis in the series of solvolyses. It has been concluded that the solvolyses 4-methylbenzyl bromide, 3,4-dimethylbenzyl bromide, 4-phenylbenzyl bromide and 4-tert-butylbenzyl bromide proceed through the SN2 reaction mechanism whereas the solvolyses of 4-phenoxybenzyl bromide and 4-(methyltio)benzyl bromide proceed through the SN1 mechanism.

• Keywords: Hammett-Brownova korelacija; solvoliza
• Keywords (english): Hammett-Brown correlation; solvolysis
• Language: croatian
• URN:NBN: urn:nbn:hr:163:052437
• Study programme: Title: Pharmacy; Study programme type: university; Study level: integrated undergraduate and graduate; Academic / professional title: magistar/magistra farmacije (magistar/magistra farmacije)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2022-02-09 13:27:15