Nitration Nitroalcohols

A very attractive method for the preparation of nitroalkenes, which is based on the reaction with NO, has been reported. Treatment of alkenes at ambient pressure of nitrogen monoxide (NO) at room temperature gives the corresponding nitroalkenes in fairly good yields along with P-nitroalcohols in a ratio of about 8 to 2. The nitroalcohol by-products are converted into the desired nitroalkenes by dehydration with acidic alumina in high total yield. This simple and convenient nitration procedure is applied successfully to the preparation of nitroalkenes derived from various terminal alkenes or styrenes (Eq. 2.27).53 This process is modified by the use of HY-zeolites instead of alumina. The lack of corrosiveness and the ability to regenerate and reuse the catalyst make this an attractive system (Eq. 2.28).54... 

Alkenes can react with nitric acid, either neat or in a chlorinated solvent, to give a mixture of compounds, including v/c-dinitroalkane, jS-nitro-nitrate ester, v/c-dinitrate ester, /3-nitroalcohol, and nitroalkeneproducts. Cyclohexene reacts with 70 % nitric acid to yield a mixture of 1,2-dinitrocyclohexane and 2-nitrocyclohexanol nitrate. Frankel and Klager investigated the reactions of several alkenes with 70 % nitric acid, but only in the case of 2-nitro-2-butene (1) was a product identified, namely, 2,2,3-trinitrobutane (2). 

The reaction of fuming nitric acid with 2-methyl-2-butene (3) is reported to yield 2-methyl-3-nitro-2-butene (4). The reaction of alkenes with fuming nitric acid, either neat or in chlorinated solvents, is an important route to unsaturated nitrosteroids, which assumedly arise from the dehydration of /3-nitroalcohols or the elimination of nitric acid from /3-nitro-nitrate esters. Temperature control in these reactions is important if an excess of oxidation by-products is to be avoided. 

Esters of nitroalcohol and unsaturated acids Industrial mcth(xls of nitrating alkanes German method tjf nitration of lower alkanes Method of Commercial Stdvcnis Corporation, Inc. 

Liquid-phase Nitration of Olefins. Although this reaction has been known for some time, it had never been of any preparative value until the work of Levy and Scaife, who showed that under the proper conditions the work could be carried out safely and products could be obtained in good yield. Nitrogen dioxide is the nitrating agent, and air is added to oxidize any nitric oxide to the dioxide. The initial products are the dinitroparaffin and a nitronitrite. The latter is unstable and is partially oxidized to the stable nitronitrate by the air. The remaining nitronitrite is converted to the nitroalcohol by treatment of the reaction product with water or ethanol before distillation. 

The preparation of nitroaUtane is very difficult, and it is more difficult to prepare nitro alcohols. In most of the early nitroalcohol preparation methods, oxidation nitration method was used to obtain the target products, DNPOH [37, 38] was also produced with oxidation nitration method and chlorination nitration method [39]. Disadvantages of these nitro alcohol preparation methods is The oxidized nitration... 

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