| 摘要 |
<p>The organic substances, e.g. aldehydes, ketones, nitro and nitroso cpds. azo and azoxy cpds. and esp. azines, phenazines, dioxazines and quinoid cpds. such as indigo and anthraquinone cpds. forming vat dyes, are reduced with formaldehyde sulphoxylates, sulphoxylic acid or a salt thereof, the reduced substance then being isolated or converted into a stable prepn. Reduction may also be effected with alkali(ne earth) boronates in the presence of oxygenated and hydrated cpds. of tri- or tetravalent S which are less alkaline than sodium sulphite or in the presence of oxygenated cpds. of bivalent S or of substances which are convertible into thio-derivs. of this type under the reaction conditions prevailing, suitably thiourea dioxide. The reduced substance is then isolated or converted into a stable prepn.</p> |
