Amineborane: a unique reductive bleaching agent that protects cystine disulphide bonds in keratins

Abstract

This paper reports a new application for amineboranes in the bleaching of wool, a typical example of keratin fibre. It has been found in this investigation that amineboranes are unique reductive bleaching agents that do not attack cystine disulphide bonds in wool keratin and do not impart permanent set to the fibre during bleaching. Selected amineborane compounds can be used in conjunction with oxidative agents such as hydrogen peroxide in aqueous media to further enhance the whitening effect and prevent disulphide bond disruption in keratins. The results of this study have suggested that the researched technology outperforms existing bleaching methods on a number of levels and may be an important step towards a new commercial bleaching technology.

Application of Micro-Suspended System in Bleaching Process of Natural Pigmented Animal Fiber

“…Divalent ferrous iron ion has a strong bond with conjugated link of chromophoric groups, but not reacting with keratin. When it complexes with conjugated link, HO 2will be released from hydrogen peroxide, and active oxygen will directly reacting with conjugated link to destroy the chromophoric groups for the purpose of bleaching [1]. This, oxidation bleach, can't make the fiber meet the requirements of subsequent processing, so the follow-up reductive bleach has to be conducted to enhance the whiteness of the fiber.…”

“…Either in the wool or in the special animal fibers, there contains a great deal of pigmented fiber, such as the brown cashmere which accounts for 60% of total production of cashmere [1], the fox cashmere which has a hollow structure and good performance in thermal insulation, and the camel hair etc. As the motley wool and the special animal fibers have their own inherent color, it leads to a big problem in the colorful and high-grade clothing manufacturing, which is known as Natural Color [1]. Before this sort of fiber is being dyed light color, it must be bleached in the first place.…”

One-Pot Synthesis of Ammonia–Borane and Trialkylamine–Boranes from Trimethyl Borate

“…Amine–boranes, with their wide range of reactivity, have found numerous applications in organic synthesis. , Apart from their traditional use as reagents for the reduction of carbonyls, reductive amination, hydroboration of alkenes, and transfer hydrogenation, amine–boranes have also been employed as curing agents or accelerators for the preparation of epoxy resins, as reductive bleaching agents, and in electroless plating applications . More recently, the synthesis of nanoparticles using amine–boranes has attracted substantial attention from materials chemists .…”

“…Utilization of either LAH or LiH/AlCl 3 under mild conditions, in contrast to the relatively expensive NaH and energy-intensive reaction (high temperature) conditions used in the industrial protocol, makes this scalable process more economical. We believe that this synthesis will find applications in organic synthesis − and the efficient synthesis of ammonia–borane will aid in hydrogen storage research.…”