T-Butyl nitrite

One of the two enthalpies of formation for the tertiary alkyl nitrites is most probably incorrect. As seen in Table 1, not only is the slope for the liquid-phase data less negative than that for the gas-phase data, but it is much less steep than all other liquid-phase data of which we know. Part of the discrepancy is due to the inverted order of the archival enthalpies of vaporization t-butyl nitrite = 34.4 kJmol-1 and t-pentyl nitrite = 33.5 kJ mol 1. 

Many alkyl nitrites are thermally imstable and may readily decompose or explode on heating [1]. Methyl nitrite explodes more violently than ethyl nitrite [2]. Lower alkyl nitrites have been known to decompose and burst the container, even in refrigerated storage [3]. Individually indexed compounds are t Butyl nitrite, 1658 t tert-Butyl nitrite, 1659... 

The Barton reaction is strongly inhibited by the addition of t-butyl nitrite, unpublished observations at the Institute. 

One of the drawbacks of the Sandmeyer reaction is the number of competing side reactions leading to the formation of biaryls, azo compounds and phenols. A recent procedure to maximise the yield of aryl halide involves treatment of the arylamine with t-butyl nitrite and anhydrous copper(n) halide (the chloride or the bromide) in acetonitrile at 65 °C.28 The method is illustrated by the preparation of p-chloronitrobenzene (Expt 6.73) the overall reaction may be represented as ... 

An effective reagent is aqueous hypophosphorus acid, and an example of its use has been described in detail for the synthesis of 3,3 -dimethylbiphenyl from 4,4 -diamino-3,3 -dimethylbiphenyl (o-tolidine).30 As the latter compound is carcinogenic its preparation is ill-advised. More recently the deamination of diazonium salts with t-butyl nitrite in dimethylformamide has been shown to have wide applicability.31 The reaction proceeds smoothly at 65 °C with the evolution of nitrogen gas, the volume of which may be measured and used to monitor the reaction. The mechanism of the reaction is thought to involve the following radical sequence in which the solvent (DMF = solH), is the hydrogen donor. 

Base-catalysed nitrosation of acetone by t-butyl nitrite to give l-hydroxyimino-2-oxopropane [H3C-C(=0)-CH=N0H] has been studied by ab initio methods.89 Using a sodium enolate route, the cation participates to give Z-isomer, whereas a naked enolate calculation results in the -product being favoured. 

The product from Step 3 (114 mmol) was dissolved in 100 ml dimethyl disulfide and added dropwise to t-butyl nitrite (170 mmol) containing copper powder (20 g) in 30 ml... 

Until relatively recently no kinetic studies on the nitrosation of alcohols had been reported, presumably since the reactions are very rapid and require special techniques. Some kinetic measurements on the reverse reaction, the hydrolysis of alkyl nitrites have been reported here conventional kinetic methods were used. Early workers examined the reactions of the series methyl, ethyl, i-propyl and t-butyl nitrites in an acetic acid-acetate buffer and found a small increase in rate constant along the series (Skrabal et a ., 1939). Later Allen measured the rate constants for the hydrolysis of a number of alkyl nitrites in aqueous dioxan solvent for both acid- and base-catalysed reactions (Allen, 1954). The rate constants for the O-nitrosation of alcohols were determined indirectly by measurement of the overall equilibrium constant for the process, by noting the change in the rate constant for the nitrosation of phenol in the presence of added alcohols. These, combined with the known data for the reverse hydrolysis reaction, enabled the rate constants for the forward reaction to be obtained (Schmid and Riedl, 1967). The reactivity sequence MeOH > EtOH > i-PrOH > t-BuOH was deduced, and attributed to a steric effect. 

Other leaving groups are effective in the oxidative addition with Pd , and can lead to efficient Heck reactions. An attractive possibihty is an aniline as starting material, with in situ generation of a diazonium salt. While the oxidation of the amino group can occur with Pd° alone at elevated temperatures, dehberate addition of t-butyl nitrite leads to... 

Scheme 206 Use of MODD/t-butyl nitrite as methyl isocyanate precursor.

In one of the most elegant applications of gas-phase inhibition by nitric oxide, Birss, Danby and Hinshelwood have studied the thermal dissociation of r-butyl peroxide. The low temperatures required for pyrolysis permitted mass spectro-metric determination of t-butyl nitrite, and a fairly complete kinetic analysis of the system was possible. The rate of decomposition of peroxide was related to the consumption of nitric oxide and to the appearance of butyl nitrite during the inhibition period, and curves were obtained which showed the acetone and ethane concentrations as a function of time during and after inhibition. 

Problem 13.51 Inorganic acids such as f SO H3P04, and HOC1 (hypochlorous acid) form esters. Write structural formulas for (a) dimethyl sulfate, (b) tribenzyl phosphate, (c) diphenyl hydrogen phosphate, (d) t-butyl nitrite, (e) lauryl hydrogen sulfate (lauryl alcohol is -CnII23CII2OII), (/) sodium lauryl sulfate. 

At this time, it was reported that the (CH3CN)2Pd(N02)Cl / CuCl2 catalyst in tBuOH was quite selective for making aldehydes from simple alpha olefins. We decided to examine this catalyst by IR spectroscopy to see if the nitro group was transferred from Pd to the olefin substrate as was the case for our catalyst. In fact we found a much simpler process when CuCl2 was added, the nitro group was immediately transferred from palladium to t-butanol to give t-butyl nitrite. 

We next tested our nitro-free formulation in tBuOH and found that it also gave high yields of aldehyde, along with the corresponding methyl ketone (Figure 2, Table 1). Catalyst lifetimes seem to be very good as we have never seen definite signs of deactivation. The addition of t-butyl nitrite tended to reduce olefin isomerization but it also reduced the aldehyde yield. 

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