No abstract

Peroxycarboxylic acids are increasingly used as bleaching agents for the laundering process. These peroxy acids can be added as such to the wash liquor or may be generated in situ by reaction of a precursor component with hydrogen peroxide. Bleaching effectiveness appears to be determined by a delicate balance of chemical reactions of peroxy acid with the staining dyes and the rate of peroxy acid decomposition under the prevailing conditions. To improve our understanding of the chemistry involved we have carried out a systematic study using a range of aromatic and aliphatic mono‐ and diperoxycarboxylic acids with various carbon chain lengths and degrees of branching. We investigated peroxy acid decomposition, bleaching of stained fabric and bleaching of a water‐soluble dye, and showed that the alkyl chain length of the peroxy acids, the presence of detergent components and the pH of the medium are important factors. Combination of the kinetic data for decomposition and bleaching reactions allows the selection of structures and conditions for optimum performance.

Association numbers of magnesium compounds in tetrahydrofuran have been investigated. One Mg‐atom is incorporated in the molecules of the Grignard reagent, of MgBr2, and of Et2Mg.

In co-oxidations of aldehydes and olefins with molecular oxygen in the liquid phase, epoxides are formed via two different routes: (1) by reaction of intermediate acylperoxy radicals with the olefin, and (2) by a non-radical reaction of intermediate peracid with the olefin. For the systems benzaldehyde cis-l,2-D,-1 -octene and benzaldehyde cis-and trans-2-octene the ratio of radical to non-radical epoxidation has been calculated with the aid of the kinetic relationships derived for this type of reaction and has been determined experimentally from the stereo selectivity of the expoxidation and from the production of carbon dioxide. The results show that the ratio of radical to non-radical epoxidation increases with increasing reactivity of the olefm as well with increasing olefin/ aldehyde ratio.

Durch Assoziationsmessungen wird festgestellt, daB die aus 3.3'-Dibrom-di-n-propylather (3) erhaltliche Di-Grignard-Verbindung 1 in Tetrahydrofuran vollstandig zu monomerem I-Oxa-5-magnesiacyclooctan (2) und Magnesiumbromid disproportioniert. Die Bevorzugung von 2 wird auf intramolekulare Koordination zwischen Magnesium und Sauerstoff zuriickgefuhrt. Bei hoherer Temperatur zersetzt sich 2 zu Cyclopropan und trimerem 1 -0xa-2-magnesiacyclopentan (6a). Bifunctional and Cyclic Organomagnesium Compounds, II. -I-Oxa-5-magnesiacyclooctaneFrom association measurements it is concluded that the di-Grignard compound 1 formed from 3,3'-dibromodi-n-propyl ether (3) in tetrahydrofuran completely disproportionates to monomeric I-oxa-5-magnesiacyclooctane (2) and magnesium bromide. The preference for 2 is ascribed to intramolecular coordination between magnesium and oxygen. At higher temperatures 2 decomposes to cyclopropane and trimeric I-oxa-2-magnesiacyclopentane (6a).