Search results
Results from the WOW.Com Content Network
Selenium dioxide is prepared by oxidation of selenium by burning in air or by reaction with nitric acid or hydrogen peroxide, but perhaps the most convenient preparation is by the dehydration of selenous acid. 2 H 2 O 2 + Se → SeO 2 + 2 H 2 O 3 Se + 4 HNO 3 + H 2 O → 3 H 2 SeO 3 + 4 NO H 2 SeO 3 ⇌ SeO 2 + H 2 O
The Riley oxidation is a selenium dioxide-mediated oxidation of methylene groups adjacent to carbonyls. It was first reported by Harry Lister Riley and co-workers in 1932. [ 1 ] In the decade that ensued, selenium -mediated oxidation rapidly expanded in use, and in 1939, Andre Guillemonat and co-workers disclosed the selenium dioxide-mediated ...
Selenium can exist with oxidation state −2, +2, +4, +6. Se(II) is the dominant form in organoselenium chemistry. Se(II) is the dominant form in organoselenium chemistry. Down the group 16 column, the bond strength becomes increasingly weaker (234 kJ / mol for the C−Se bond and 272 kJ/mol for the C−S bond) and the bond lengths longer ( C ...
Selenium forms two oxides: selenium dioxide (SeO 2) and selenium trioxide (SeO 3). Selenium dioxide is formed by the reaction of elemental selenium with oxygen: [5] + It is a polymeric solid that forms monomeric SeO 2 molecules in the gas phase. It dissolves in water to form selenous acid, H 2 SeO 3.
The conversion of valencene to nootkatone is an example of allylic oxidation. In the synthesis of some fine chemicals, selenium dioxide is used to convert alkenes to allylic alcohols: [15] R 2 C=CR'-CHR" 2 + [O] → R 2 C=CR'-C(OH)R" 2. where R, R', R" may be alkyl or aryl substituents.
Selenium dioxide, SeO 2; Selenium trioxide, SeO 3; Diselenium pentoxide, Se 2 O 5 This page was last edited on 28 August 2024, at 05:38 (UTC). Text is available under ...
Allyl alcohols in general are prepared by allylic oxidation of allyl compounds, using selenium dioxide or organic peroxides. Other methods include carbon-carbon bond-forming reactions such as the Prins reaction, the Morita-Baylis-Hillman reaction, or a variant of the Ramberg-Bäcklund reaction. Hydrogenation of enones is another route.
Date/Time Thumbnail Dimensions User Comment; current: 09:15, 25 April 2011: 2,470 × 1,503 (47 KB): DMacks: convert text to paths in Inkscape (avoids WMF svg rendering bug when displayed in articles)