Pretvorbe halogeniranih in halkogeniranih organskih spojin po načelih zelene kemije

Zupanc, Anže (author), Jereb, Marjan (mentor)

V doktorskem delu smo predstavili nekatere nove sintezne metode, spojine, reagente v okviru organske kemije halogenov in halkogenov s poudarkom na načelih zelene kemije in trajnostnem razvoju. Zaradi netrajnostne rabe naravnih virov in onesnaževanja okolja se je razvilo področje, imenovano zelena kemija, ki temelji na okolju prijaznih principih. Med hal(k)ogeniranimi organskimi spojinami najdemo mnoge materiale, topila, reagente, sintone in naravne spojine ter medicinsko, industrijsko in agrokemijsko pomembne spojine. Kljub hitremu napredku na področju, se pojavljajo potrebe po sintezi obstoječih in novih motivov pod alternativnimi pogoji, ki sledijo načelom trajnostnega razvoja. Organske sulfokside smo do sulfidov reducirali na vodnem mediju 37% HCl s cenenim reagentom NaSH, ki po koncu reakcije tvori okolju nenevarne odpadne produkte. Produkt reakcije v večjem merilu smo izolirali z neposredno destilacijo. Razvili smo novo, hitro in priročno metodo oksidacije organskih sulfidov, ki pri zelenih pogojih slelektivno poteka s t-BuOCl. Pretvorbe so odvisne od temperature in topila, sulfokside in sulfone pa smo izolirali z odstranitvijo topila in hlapnih primesi. Metodo smo prenesli na večje merilo in na polimerne substrate ter raziskovali mehanizem. Prej neznane N-jodo sulfoksimine smo pripravili neposredno iz sulfidov z eno-lončnim sintetskim pristopom v zelenem topilu metanolu. Metodo smo izvedli v večjem merilu in predstavili nekatere nadaljnje pretvorbe. Organske selenide smo do selenoksidov oksidirali s 30% vodno raztopino zelenega oksidanta H2O2. Pripravili smo dva reagenta za elektrofilno selenocianiranje in -SeCN uvedli pod trajsnotnimi pogoji. 2-Amino-4H-pirane smo pod reakcijskimi pogoji brez topil s t-BuOCl regioselektivno klorofukcionalizirali do α,N-dikloroiminov in produkte izolirali z odstranjevanjem hlapnih primesi. Zlato smo raztopili v etanolu s katalitsko količino joda, 33% vodne raztopine H2O2 ter cenenim in nenevarnim ligandom. Doktorska naloga predstavlja pomemben doprinos k zeleni kemiji redoks reakcij žveplovih in selenovih organskih spojin, elektrofilnega prenosa halogenov in halkogenov ter njihovih funkcionalnih skupin, sintezi in reaktivnosti haloiminskega stukturnega motiva in recikliranja dragocenih kovin.

• Language: Slovenian
• Keywords: zelena kemija, organska kemija, halogen, halkogen, oksidacija, redukcija, sulfid, sulfoksid, sulfon, sulfoksimin, selenid, selenoksid, haloimin, klorofunkcionalizacija, selenocianat, elektrofilni prenos, žveplo, selen, jod, klor, zlato, recikliranje, kataliza
• Work type: Doctoral dissertation
• Typology: 2.08 - Doctoral Dissertation
• Organization: FKKT - Faculty of Chemistry and Chemical Technology
• Year: 2022
• PID: 20.500.12556/RUL-141447
• COBISS.SI-ID: 126027523
• Publication date in RUL: 29.09.2022

Secondary language

• Language: English
• Title: Transformations of halogenated and chalcogenated organic compounds following the principles of green chemistry

Abstract

Herein we present some novel synthetic methods, compounds and reagents in the context of halogen and chalcogen organic chemistry with emphasis on green chemistry principles and sustainable development. Due to unsustainable exploitation of natural resources and environmental pollution, green chemistry was established on environmentally friendly principles. Halogenated and chalcogenated organic compounds are important materials, solvents, reagents, synthons and natural compounds, that are used in medicine, industry, and agrochemistry. Despite quick development of this field, there is still a great need for preparation of existing and novel motifs under alternative conditions that follow sustainable development. Organic sulfoxides were deoxygenated to sulfides using 37% aqueous HCl and affordable reagent NaSH, that produce environmentally benign waste. Product of scaled-up reaction was isolated by direct distillation. New, rapid, and convenient method for oxidation of organic sulfides that selectively proceeds with t-BuOCl under green reaction conditions. Reaction was temperature- and solvent-dependent and product sulfoxides and sulfones were isolated by removal of solvent. The method was easily scalable and tested on polymeric substrate. The mechanism was explored. Previously unknown N-iodo sulfoximines were prepared from sulfides via one-pot approach in green solvent methanol. The method was scaled-up and further transformations were explored. We developed new sustainable method for oxidation of organic selenides using 30% aqueous H2O2 solution. Two reagents for electrophilic selenocyanation were prepared and -SeCN motif was introduced under sustainable conditions. 2-Amino-4H-pyrans were regioselectively chloro-functionalised with t-BuOCl under neat reaction conditions to afford α,N-dichloroimines that were isolated by removal of volatiles. Gold was dissolved in ethanol with catalytic amount of iodine, 33% aqueous H2O2 and inexpensive and non-toxic ligand. Doctoral thesis presents an important contribution to green chemistry topics of sulfur and selenium organic compound redox reactions, halogen and chalcogen functional group electrophilic transfer and synthesis, reactivity of haloimine structural motif and noble metal recycling.

• Keywords: green chemistry, organic chemistry, halogen, chalcogen, oxidation, reduction, sulfide, sulfoxide, sulfone, sulfoximine, selenide, selenoxide, haloimine, chlorofunctionalisation, selenocyanate, electrophilic transfer, sulphur, selenium, iodine, chlorine, gold, recycling, catalysis