Ozonide

Ozonides. Ozonolysis is a powerful method for cleaving alkenes to carbonyl products (sec. 3.7.B). Ozonolysis of alkenes initially generates an ozonide that can be reduced by a variety of reagents. Dimethyl sulfide or zinc in acetic acid are the most common reagents for the reduction of an ozonide to an aldehyde or ketone. Reduction of the ozonide with the more powerful lithium aluminum hydride, however, gives direct conversion to the alcohol. 

Some studies have also been made on the action of ozone on elastomers such as natural rubber, neoprene, etc. [8]. In these cases, however, there is no suggestion of the detection of any ozonides, but only of decomposition products characterised by OH and carbonyl absorptions. 

Lecomte, Traite de Chimie Organique (ed. Grignard et Baud, Masson et Cie, 

Barnes, Gore, Liddel and Van Zandt Williams, Infra-red Spectroscopy 

Randall, Fowler, Fuson and Dangl, Infra-red Determination of Organic 

Herzberg, Infra-red and Raman Spectra of Polyatomic Molecules (Van 

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Addition compounds called ozonides are produced when alkenes react with ozone and reductive cleavage of these compounds is used extensively in preparative and diagnostic organic chemistry. 

How would you obtain a sample of pure ozone Account for the conditions used in your method of preparation. What is the arrangement of oxygen atoms in an ozonide and what evidence would you cite in support of the structure you suggest ... 

Excess of ozone should be avoided since further oxidation may occur to oxozonides or perozonides. ) The ozonides are usually not isolated since they are generally viscid oils or glasses, sometimes with violently explosive properties particularly on warming. They can, however, be completely... 

Organic peroxides are highly explosive, hence it is best to carry out the ozonisation in a solvent which dissolves both the original compound and the ozonide. 

Ozonides undergo hydrolysis in water giving carbonyl compounds... 

Aldehydes are easily oxidized to carboxylic acids under conditions of ozonide hydroly SIS When one wishes to isolate the aldehyde itself a reducing agent such as zinc is included during the hydrolysis step Zinc reduces the ozonide and reacts with any oxi dants present (excess ozone and hydrogen peroxide) to prevent them from oxidizing any aldehyde formed An alternative more modem technique follows ozone treatment of the alkene m methanol with reduction by dimethyl sulfide (CH3SCH3)... 

This cleavage reaction is more often seen in structural analysis than in synthesis The substitution pattern around a dou ble bond is revealed by identifying the carbonyl containing compounds that make up the product Hydrolysis of the ozonide intermediate in the presence of zinc (reductive workup) permits aide hyde products to be isolated without further oxidation... 

Palladium Arsenic, carbon, ozonides, sulfur, sodium tetrahydridoborate... 

A 38.63-mg sample of potassium ozonide, KO3, was heated to 70 °C for 1 h, undergoing a weight loss of 7.10 mg. Write a balanced chemical reaction describing this decomposition reaction. A 29.6-mg sample of impure KO3 experiences a 4.86-mg weight loss when treated under similar condition. What is the %w/w KO3 in the sample ... 

Secondary ozonide Secondary plasticizer Secondary recycling Secondary structures Secosteroid... 

The relevant properties of peroxide and superoxide salts are given in Table 4 (see Peroxides and peroxide compounds, inorganic). Potassium peroxide is difficult to prepare and lithium superoxide is very unstable. The ozonides, MO3, of the alkah metals contain a very high percentage of oxygen, but are only stable below room temperature (see Ozone). 

Oxygen Compounds. Although hydrogen peroxide is unreactive toward ozone at room temperature, hydroperoxyl ion reacts rapidly (39). The ozonide ion, after protonation, decomposes to hydroxyl radicals and oxygen. Hydroxyl ions react at a moderate rate with ozone (k = 70). 

Formation of Ozonides. Although the patent compound, HO3, is too unstable to be isolated, metal and nonmetal ozonides have been... 

The stability of the alkali metal ozonides increases from Li to Cs alkaline-earth ozonides exhibit a similar stability pattern. Reaction of metal ozonides with water proceeds through the intermediate formation of hydroxyl radicals. 

The unstable ammonium ozonide [12161 -20-5] NH O, prepared at low temperatures by reaction of ozone withHquid ammonia, decomposes rapidly at room temperature to NH NO, oxygen, and water (51). Tetrametbylammonium ozonide [78657-29-1] also has been prepared. 

Ozonation ofAlkenes. The most common ozone reaction involves the cleavage of olefinic carbon—carbon double bonds. Electrophilic attack by ozone on carbon—carbon double bonds is concerted and stereospecific (54). The modified three-step Criegee mechanism involves a 1,3-dipolar cycloaddition of ozone to an olefinic double bond via a transitory TT-complex (3) to form an initial unstable ozonide, a 1,2,3-trioxolane or molozonide (4), where R is hydrogen or alkyl. The molozonide rearranges via a 1,3-cycloreversion to a carbonyl fragment (5) and a peroxidic dipolar ion or zwitterion (6). 

The dipolar ion can react in several ways according to the solvent and the stmcture of the olefin. In inert solvents, if the carbonyl compound is highly reactive (eg, an aldehyde), the dipolar ion can be added to the carbonyl fragment to give the normal ozonide or 1,2,4-trioxolane (7) for example, 1,1-and 1,2-dialkylethylenes react in this manner. Tri- or tetraalkyl-substituted olefins produce a smaH, if any, yield of an ozonide when the ozonolysis is... 

Commercially, pure ozonides generally are not isolated or handled because of the explosive nature of lower molecular weight species. Ozonides can be hydrolyzed or reduced (eg, by Zn/CH COOH) to aldehydes and/or ketones. Hydrolysis of the cycHc bisperoxide (8) gives similar products. Catalytic (Pt/excess H2) or hydride (eg, LiAlH reduction of (7) provides alcohols. Oxidation (O2, H2O2, peracids) leads to ketones and/or carboxyUc acids. Ozonides also can be catalyticaHy converted to amines by NH and H2. Reaction with an alcohol and anhydrous HCl gives carboxyUc esters. 

AH of the commercial inorganic peroxo compounds except hydrogen peroxide are described herein, as are those commercial organic oxidation reactions that are beheved to proceed via inorganic peroxo intermediates. Ozonides and superoxides are also included, but not the dioxygen complexes of the transition metals. 

The ozonides are characterized by the presence of the ozonide ion, O - They are generally produced by the reaction of the inorganic oxide and ozone (qv). Two reviews of ozonide chemistry are available (1,117). Sodium ozonide [12058-54-7] NaO potassium ozonide [12030-89-6] 35 rubidium ozonide [12060-04-7] RbO and cesium ozonide [12053-67-7] CsO, have all been reported (1). Ammonium ozonide [12161 -20-5] NH O, and tetramethylammonium ozonide [78657-29-1/, (CH ) NO, have been prepared at low temperatures (118). 

Organic peroxides can be classified according to peroxide stmcture. There are seven principal classes hydroperoxides dialkyl peroxides a-oxygen substitued alkyl hydroperoxides and dialkyl peroxides primary and secondary ozonides peroxyacids diacyl peroxides (acyl and organosulfonyl peroxides) and alkyl peroxyesters (peroxycarboxylates, peroxysulfonates, and peroxyphosphates). 

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