master's thesis
Nucleofugality of ethyl-carbonates in aqueous acetonitrile solutions

Matija Katić (2015)
Sveučilište u Zagrebu
Farmaceutsko-biokemijski fakultet
Zavod za organsku kemiju
Metadata
TitleNukleofugalnost etil-karbonata u vodenim otopinama acetonitrila
AuthorMatija Katić
Mentor(s)Mirela Matić (thesis advisor)
Abstract
Izmjerene su brzine solvolize sintetiziranih spojeva: 4,4'-dimetoksibenzhidril-etil-karbonata, 4-metoksibenzhidril-etil-karbonata, 4-metoksi-4'-fenoksibenzhidril-etil-karbonata i 4-metoksi-4'-metilbenzhidril-etil-karbonata u 60%-tnoj i 80%-tnoj vodenoj otopini acetonitrila. Pomoću izračunatih brzina solvolize konstruiran je graf ovisnosti log k o Ef vrijednostima koji je pokazao izvrsnu linearnu korelaciju. Primjenom jednadžbe pravca, log k (25 °C) = sf (Nf + Ef), izračunati su parametri nukleofugalnosti etil-karbonata, i iznose: Nf = –2,85 i sf = 0,99 u 80%-tnom acetonitrilu, te Nf = –2,54 i sf = 0,90 u 60%-tnom acetonitrilu. Usporedbom vrijednosti izmjerenih u dvije vrste otapala uočeno je da se povećanjem udjela vode u otapalu, odnosno povećanje polarnosti otapala povećava reaktivnost izlazne skupine tj. nukleofugalnost, a smanjuje vrijednost sf, što je u skladu s prethodno dobivenim rezultatima za metil- i fenil-karbonate. Prema reaktivnosti u vodenim otopinama acetonitrila, etilkarbonat se smjestio među manje reaktivne izlazne skupine pri čemu je tosilatna najreaktivnija (Nf/sf =7,97/0,82 u 60% acetonitrilu), a 2,2-dimetilpropanoatna (Nf/sf = –5,32/1,02 u 60% acetonitrilu) najmanje reaktivna izlazna skupina.
Keywordscarbonates benzhydrylium substrates solvolysis kinetics electrofugality nucleofugality
Parallel title (English)Nucleofugality of ethyl-carbonates in aqueous acetonitrile solutions
Committee MembersMirela Matić
Bernard Denegri
Ivana Perković
GranterSveučilište u Zagrebu
Farmaceutsko-biokemijski fakultet
Lower level organizational unitsZavod za organsku kemiju
PlaceZagreb
StateCroatia
Scientific field, discipline, subdisciplineBIOMEDICINE AND HEALTHCARE
Pharmacy
Pharmacy
Study programme typeuniversity
Study levelintegrated undergraduate and graduate
Study programmePharmacy
Academic title abbreviationmag. pharm.
Genremaster's thesis
Language Croatian
Defense date2015-09-28
Parallel abstract (English)
The rate constants of solvolysis have been determined for synthesized compounds: 4,4'-dimethoxybenzhydryl ethyl carbonate, 4-methoxybenzhydryl ethyl carbonate, 4-methoxy-4'-phenoxybenzhydryl ethyl carbonate and 4-methoxy-4'-methylbenzhydryl ethyl carbonate in 80 % aqueous acetonitrile and 60 % aqueous acetonitrile. The observed and calculated rate constants of solvolysis have been used for plotting log k vs. Ef - value graph which shows great linear correlation. The equation log k (25 °C) = sf (Nf + Ef) was used to calculate Nf and sf values in 80 % aqueous acetonitrile and 60 % aqueous acetonitrile. Obtained values are Nf = –2,85 and sf = 0,99 in 80 % aqueous acetonitrile and Nf = –2,54 and sf = 0,90 in 60 % aqueous acetonitrile. By comparing this values it can be seen that Nf value decreases as the water content in the solution increases, ie. the more polar solvent is, leaving group is more reactive, while sf value decreases, which is in correspondence with previously known results for methyl and phenyl carbonates. According to reactivity in aqueous acetonitrile solutions, ethyl carbonate is less reactive leaving group, on the scale on which tosylate group is the most reactive, Nf/sf = 7,97/0,82 in 60 % aqueous acetonitrile and pivalate group is the least reactive Nf/sf = –5,32/1,02 in 60 % aqueous acetonitrile.
Parallel keywords (Croatian)karbonati benzhidrilni supstrati solvoliza kinetika nukleofugalnost elektrofugalnost
Resource typetext
Access conditionOpen access
Terms of usehttp://rightsstatements.org/vocab/InC/1.0/
URN:NBNhttps://urn.nsk.hr/urn:nbn:hr:163:694418
CommitterPetra Gašparac