Johanna Kärkkäinen

Dissolution and depolymerization of barley starch in selected ionic liquids

Polysaccharides like starch are poorly soluble in common solvents. However, certain ionic liquids (ILs) have been found to dissolve them, although some depolymerization happens during the dissolution. Dissolution and depolymerization of barley starch in ten ionic liquids have been studied with p-TsOH as a catalyst under controlled microwave heating. Dissolution time and the extent of the depolymerization of starch, determined by using HPLC-ELSD, were specific to each IL. Dialkylimidazolium halide ILs dissolved starch fast and depolymerized it substantially producing 79-100% water-soluble starch oligomers with the average molecular weight of 1000-2000Da. 1-Ethyl-3-methylimidazolium phosphate ([EMIM][Me2PO4]) and 2-hydroxyethylammonium formate ([NH3CH2CH2OH][HCOO]) dissolved starch slowly and depolymerized it least among the tested ILs. For the slow depolymerization of starch these ILs can be considered as suitable solvents for starch modifications where its depolymerization should be avoided.

Synthesis And Structural Characterization Of 1-Butyl-2,3-Dimethylimidazolium Bromide And Iodide

1-Butyl-2,3-dimethylimidazolium bromide {(bdmim)Br} (1) and iodide {(bdmim)I} (2) were prepared conveniently by the reaction of 1,2-dimethylimidazole and the corresponding 1-halobutane. The compounds were characterized by 1H and 13C{1H} NMR spectroscopy as well as by X-ray single crystal crystallography. 1 crystallizes in the monoclinic crystal system, space group P21/n, with Z = 4, and unit cell dimensions a = 8.588(2), b = 11.789(1), c = 10.737(2) Å, β = 91.62(3)°. Compound 2 crystallizes in the monoclinic crystal system, space group P21/c, with Z = 8, and unit cell dimensions a = 10.821(2), b = 14.221(3), c = 15.079(2) Å , β = 90.01(3)°. The lattices of the salts are built up of 1-butyl-2,3- dimethylimidazolium cations and halide anions. The cations of 1 form a double layer with the imidazolium rings stacked together due to π interactions. The Br− anions lie approximately in the plane of the imidazolium ring, and the closest interionic Br···H contacts span a range of 2.733(1) - 2.903(1) Å. Compound 2 shows no π stacking interactions. The closest interionic I···H contacts are 2.914(1) - 3.196(1) Å

Effect of temperature on the purity of product in the preparation of 1-butyl-3-methylimidazolium-based ionic liquids

The preparation of room-temperature ionic liquids 1-butyl-3-methylimidazolium chloride, hexafluorophosphate, and dicyanamide by microwave-assisted reaction in non-solvent and solvent conditions has been studied in this contribution. A special emphasis is put on the effect of the reaction temperature on the purity of ionic liquids that was monitored by electrospray ionisation mass spectrometry and 1H NMR. The X-ray structure of 1-butyl-3-methylimidazolium chloride is presented.

Modification of potato peel waste with base hydrolysis and subsequent cationization.

Potato peel waste (PW) is a starch containing biomaterial produced in large amounts by food processing industry. In this work, the treatment of PW by alkaline hydrolysis and cationization in the water phase is reported. In order to improve the cationization of starch, PW was hydrolyzed by heating with alkaline (NaOH) ethanol solution (80%) in a water bath. The impact of variable molar ratios of anhydroglucose unit (AGU):NaOH, heating temperatures and times was studied on the degradation of starch and the molecular size distribution of the product. The hydrolyzed PW was cationized subsequently in water by using glycidyltrimethylammonium chloride and catalyzed by NaOH under microwave irradiation or in an oil bath. The impact of the various reaction conditions on the cationization and degree of substitution of starch was studied. The degree of substitution of the cationized starch varied in the range of 0-0.35.

(1)H NMR-based DS determination of barley starch sulfates prepared in 1-allyl-3-methylimidazolium chloride.

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.

Preparation of cationized starch from food industry waste biomass and its utilization in sulfate removal from aqueous solution

In this work, untreated starch-rich potato peel waste was used as a starting material in preparation of cationized starch (CS)1 in water solution with 2-chloro-3-hydroxypropyltrimethylammonium chloride (CHPTAC) as the cationization reagent. The impact of various factors (activation time, temperature, reaction time, the amount of CHPTAC and NaOH) on the degree of substitution (DS) of CS was studied by using experimental design. The DS values were determined by 1H NMR. The highest DS (0.40) was obtained when the reaction time was 8h, temperature 30°C, the molar ratio of CHPTAC and NaOH to AGU 3 and 3.75, respectively. The prepared CS was successfully used to remove sulfate ions from an aqueous solution with ultrafiltration technique. Sulfate is a major pollutant of water bodies so development of efficient techniques for its removal is detrimental. The removal of sulfate in study was 74% at best.