Reduction and Analysis Methods of Indigo

Throughout history indigo was derived from various plants for example Dyer’s Woad (Isatis tinctoria L.) in Europe. In the 19th century were the synthetic dyes developed and nowadays indigo is mainly synthesized from by-products of fossil fuels. Indigo is a so-called vat dye, which means that it needs to be reduced to its water soluble leucoform before dyeing. Nowadays, most of the industrial reduction is performed chemically by sodium dithionite. However, this is considered environmentally unfavourable because of waste waters contaminating degradation products. Therefore there has been interest to find new possibilities to reduce indigo. Possible alternatives for the application of dithionite as the reducing agent are biologically induced reduction and electrochemical reduction. Glucose and other reducing sugars have recently been suggested as possible environmentally friendly alternatives as reducing agents for sulphur dyes and there have also been interest in using glucose to reduce indigo. In spite of the development of several types of processes, very little is known about the mechanism and kinetics associated with the reduction of indigo. This study aims at investigating the reduction and electrochemical analysis methods of indigo and give insight on the reduction mechanism of indigo. Anthraquinone as well as it’s derivative 1,8-dihydroxyanthraquinone were discovered to act as catalysts for the glucose induced reduction of indigo. Anthraquinone introduces a strong catalytic effect which is explained by invoking a molecular “wedge effect” during co-intercalation of Na+ and anthraquinone into the layered indigo crystal. The study includes also research on the extraction of plant-derived indigo from woad and the examination of the effect of this method to the yield and purity of indigo. The purity has been conventionally studied spectrophotometrically and a new hydrodynamic electrode system is introduced in this study. A vibrating probe is used in following electrochemically the leuco-indigo formation with glucose as a reducing agent.Siirretty Doriast

Sininen on väri morsingon

Mitäpä olisi pukea taivaansininen, luonnonkuituinen ja ekologisesti valmistettu juhlapuku itsenäisyysjuhlaan? Tai sujauttaa kädet talvipakkasella sinisiin lampaan pökkimiin lapasiin? Kohta sinisiin ekoelämyksiin on mahdollisuus, sillä morsinkokasvista kehitetään ympäristömyönteistä indigovärin tuotantoa.vokKV

Control of potato late blight by caraway oil in organic farming

Caraway (Carum carvi) seeds contain biologically active essential oils, which have shown potential in controlling Phytophthora infestans (P.i.). An attempt is being made to develop a P.i. control strategy for organic farming based on caraway oil

Värimorsingosta indigon-sinistä väriä

Värimorsinko on yksi harvoista sinistä indigo-väriainetta muodostavista kasveista. MTT:ssä selvitetään sen viljelyä, siementuotantoa, väriaineen eristämistä, analysointia ja väriaineen käyttöä. Tavoitteena on luoda viljelyohjeistus sinistä väriainetta tuottavalle kasville.VokKV

Kasviperäisen indigon värinkesto-ominaisuudet

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Kasviperäisen indigon suora sähkökemiallinen pelkistys

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Galvanic exchange platinization reveals laser-inscribed pattern in 3D-LAM-printed steel

Galvanic exchange involving dissolution of iron and the simultaneous growth of platinum onto 316 L stainless steel was investigated for specimens manufactured by 3D-printing, and the behavior was compared to conventional stainless steel. Novel phenomena associated with the 3D-printed steel, but not conventional steel, reacting in three distinct phases were observed: first, with low platinum loading, a bright etching pattern linked to the laser-manufacturing process is revealed at the steel surface; second, a nanostructured pore pattern with platinum nano-deposits forms; and third, a darker platinum film coating of typically 500-nm thickness forms and then peels off the steel surface with further platinum growth underneath. Unlike the conventional steel (and mainly due to residual porosity), 3D-printed steel supports well-adhered platinum films for potential application in electrocatalysis, as demonstrated for alkaline methanol oxidation. [Figure not available: see fulltext.]</p

Residual porosity of 3D-LAM-printed stainless-steel electrodes allows galvanic exchange platinisation

Stainless-steel rods were manufactured by laser additive manufacturing (LAM or "3D-printing") from a stainless-steel (316L) powder precursor, and then investigated and compared to conventional stainless steel in electrochemical experiments. The LAM method used in this study was based on "powder bed fusion", in which particles with an average diameter of 20-40μm are fused to give stainless-steel rods of 3mm diameter. In contrast to conventional bulk stainless-steel (316L) electrodes, for 3D-printed electrodes, small crevices in the surface provide residual porosity. Voltammetric features observed for the 3D-printed electrodes immersed in aqueous phosphate buffer are consistent with those for conventional bulk stainless steel (316L). Two chemically reversible surface processes were observed and tentatively attributed to Fe(II/III) phosphate and Cr(II/III) phosphate. Galvanic exchange is shown to allow improved platinum growth/adhesion onto the slightly porous 3D-printed stainless-steel surface, resulting in a mechanically robust and highly active porous platinum deposit with good catalytic activity toward methanol oxidation.</p