title: (1)H NMR-based DS determination of barley starch sulfates prepared in 1-allyl-3-methylimidazolium chloride.
abstract: The use of natural resources in a development of products and materials is currently increasing. Starch is one of the investigated resources due to its bioavailability, biodegradability, safety and affordability. In this study, native barley starch was sulfated using a SO3-pyridine complex. The reaction was carried out for the first time using 1-allyl-3-methylimidazolium chloride ionic liquid, an excellent solvent for the starch modification. Reaction conditions (temperature, time and amount of the reagent) were studied using an experimental design. Starch sulfates with the degree of substitution (DS) 1.37 were obtained when the reaction was carried out at 40 °C for 75 min with 4:1 molar ratio of SO3-pyridine complex:anhydroglucose unit. The determination of DS was based on (1)H NMR instead of elemental analysis, which showed overestimated DS values in this study. Starch sulfates were analyzed with FTIR and HPLC, which showed that products contained small and large sulfated molecules.
authors.affiliation: Research Unit of Sustainable Chemistry, University of Oulu, P.O. Box 3000, FIN-90014 University of Oulu, Finland. Electronic address: Johanna.Karkkainen@oulu.fi.
authors.forename: Johanna
authors.initials: J
authors.lastname: Kärkkäinen
authors.affiliation: Research Unit of Sustainable Chemistry, University of Oulu, P.O. Box 3000, FIN-90014 University of Oulu, Finland. Electronic address: Tiia-Riikka.Wik@student.oulu.fi.
authors.forename: Tiia-Riikka
authors.initials: TR
authors.lastname: Wik
authors.affiliation: Research Unit of Sustainable Chemistry, University of Oulu, P.O. Box 3000, FIN-90014 University of Oulu, Finland. Electronic address: Matti.Niemela@oulu.fi.
authors.forename: Matti
authors.initials: M
authors.lastname: Niemelä
authors.affiliation: Research Unit of Sustainable Chemistry, University of Oulu, P.O. Box 3000, FIN-90014 University of Oulu, Finland. Electronic address: Katja.Lappalainen@oulu.fi.
authors.forename: Katja
authors.initials: K
authors.lastname: Lappalainen
authors.affiliation: Research Unit of Sustainable Chemistry, University of Oulu, P.O. Box 3000, FIN-90014 University of Oulu, Finland. Electronic address: Paivi.Joensuu@oulu.fi.
authors.forename: Päivi
authors.initials: P
authors.lastname: Joensuu
authors.affiliation: Research Unit of Sustainable Chemistry, University of Oulu, P.O. Box 3000, FIN-90014 University of Oulu, Finland. Electronic address: Marja.Lajunen@oulu.fi.
authors.forename: Marja
authors.initials: M
authors.lastname: Lajunen
mesh_terms: D000498:Allyl Compounds / Q000737:chemistry*; D001467:Hordeum / Q000737:chemistry; D007093:Imidazoles / Q000737:chemistry*; D052578:Ionic Liquids / Q000737:chemistry; D013213:Starch / Q000031:analogs & derivatives / Q000737:chemistry*; D013431:Sulfates / Q000737:chemistry
chemical_list: C544334:1-allyl-3-methylimidazolium; D000498:Allyl Compounds; D007093:Imidazoles; D052578:Ionic Liquids; D013431:Sulfates; D013213:Starch
keywords: (1)H NMR; Barley starch; Experimental design; Ionic liquids; Sulfation