Safety hydroperoxides

Recently (79MI50500) Sharpless and coworkers have shown that r-butyl hydroperoxide (TBHP) epoxidations, catalyzed by molybdenum or vanadium compounds, offer advantages over peroxy acids with regard to safety, cost and, sometimes, selectivity, e.g. Scheme 73, although this is not always the case (Scheme 74). The oxidation of propene by 1-phenylethyl hydroperoxide is an important industrial route to methyloxirane (propylene oxide) (79MI5501). 

Safety. Since organic peroxides can be initiated by heat, mechanical shock, friction or contamination, an enormous problem in safety presents itself. Numerous examples of this problem have already been shown in this article. Additional examples include the foilowing methyl and ethyl hydroperoxides expld violently on heating or jarring, and their Ba salts also are extremely expl the alkylidene peroxides derived from low mw aldehydes and ketones are very sensitive and expld with considerable force polymeric peroxides of dimethyl ketene, -K>-0-C(CH3)2C(0)j-n, expld in the dry state by rubbing even at —80° peroxy acids, especially those of low mw, and diacetyl, dimethyl, dipropkmyl and methyl ethyl peroxides, when pure, must be handled only in small amts and... 

Common alcohol oxidation methods employ stoichiometric amounts of toxic and reactive oxidants like Cr03, hypervalent iodine reagents (Dess-Martin) and peracids that pose severe safety and environmental hazards in large-scale industrial reactions. Therefore, a variety of catalytic methods for the oxidation of alcohols to aldehydes, ketones or carboxylic acids have been developed employing hydrogen peroxide or alkyl hydroperoxides as stoichiometric oxygen sources in the presence of catalytic amounts of a metal catalyst. The commonly used catalysts for alcohol oxidation are different MoAV(VI), Mn(II), Cr(VI), Re(Vn), Fe(II) and Ru complexes . A selection of published known alcohol oxidations with different catalysts will be presented here. 

Hartree-Fock calculations, peracid alkene epoxidation, 48-50 Hazardous materials commercial codes, 621 emergency response, 746-7 environmental hazards, 747, 751-3 labels, 751-3 NIOSH Pocket Guide, 749 occupational hazards, 747-9 safety issues, 744-9 HDL see High-density lipoprotein Heat of formation see Enthalpy of formation HEHP (1-hydroxyethyl hydroperoxide), 605, 638... 

Although no obvious advantages can be seen in replacing 3-chloroperoxybenzoic acid with the tot-butyl hydroperoxide/hexacarbonylmolybdenum method, this could change in the future since several commercial suppliers of 3-chloroperoxybenzoic acid have announced that they will stop the sale of this reagent for safety reasons. 

Hydroperoxides. These can be converted to their sodium salts by precipitation below 30° with aqueous 25% NaOH. The salt is then decomposed by addition of solid (powdered) carbon dioxide and extracted with low-boiling petroleum ether. The solvent should be removed under reduced pressure below 20°. The apparatus should be adequately shielded at all times for the safety of the operator from EXPLOSIONS. 

Tertiary hydroperoxides Are usually relatively stable. However, the reactions leading to their formation are treacherous, and all safety precautions must be used to prevent serious explosions (Ref 56)... 

It is important to prevent the oxidation of edible fats and oils and of foods that contain oils to maintain their quality and safety. Oxidation of fats and oils can be initiated by heat, light, and metals in the fats and oils. The oxidation products from oils, which include hydroperoxides and cyclic peroxides, decompose to produce a variety of volatile compounds, which result in undesirable flavors and odors in oils (131-134). Oils damaged by oxidation also have been reported to cause biological problems, such as diarrhea, growth depression, and tissue damage in living organisms. 

DOT CLASSIFICATION 8 Label Corrosive SAFETY PROFILE Poison by inhalation. A corrosive irritant to the eyes, skin, and mucous membranes. With the appropriate conditions it undergoes hazardous reactions with formic acid, hydrogen fluoride, inorganic bases, iodides, metals, methyl hydroperoxide, oxidants (e.g., bromine, pentafluoride, chlorine trifluoride, perchloric acid, oxygen difluoride, hydrogen peroxide), 3-propynol, water. When heated to decomposition it emits toxic fumes of POx. 

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