N-Heptaldehyde

Dissolve 57 g. of dry malonic acid in 92 5 ml. of dry P3rridine contained in a 500 ml. round-bottomed flask, cool the solution in ice, and add 57 g. (70 ml.) of freshly distilled n-heptaldehyde (oenanthol) with stirring or vigorous shaking. After a part of the aldehyde has been added, the mixture rapidly seta to a mass of crystals. Insert a cotton wool (or calcium chloride) tube into the mouth of the flask and allow the mixture to stand at room temperature for 60 hours with frequent shaking. Finally, warm the mixture on a water bath until the evolution of carbon dioxide ceases (about 8 hours) and then pour into an equal volume of water. Separate the oily layer and shake it with 150 ml. of 25 per cent hydrochloric acid to remove pyridine. Dissolve the product in benzene, wash with water, dry with anhydrous magnesium sulphate, and distil under reduced pressure. Collect the ap-nonenoic acid at 130-13272 mm. The yield is 62 g. 

To a solution of 18.9 grams (0.166 mol) n-heptaldehyde in 25 ml of isopropanol is added, with stirring, a solution of 19,1 grams (0.166 mol) of 1-aminohydantoin in 110 ml water acidified with concentrated HCI. The heavy white precipitate formed is filtered and washed, until acid free, with small amounts of water and ether. The yield of N-(n-hBptylidenB)-1-aminohydantoin is 14 grams of MP 150°C (with decomposition). This may be recrystal-lized from dimethylformamide. 

Aldol condensation reactions have also been conducted. A good example is provided by Climent et al. (1998) for making a-n-amyl cinnamaldehyde (Jasmin aldehyde) by condensing benzaldehyde with n-heptaldehyde, in the presence of mesoporous MCM-41 aluminosilicates. Mesoporous silica-aluminas with a narrow range of pore diameter such as MCM-41 also... 

Polymers containing a benzyldiphenylphosphine complexing group are also effective. Capka et al. (109) studied the catalyst formed from this type of organic substrate and RhClv(C2H4) j. 1-Hexene was hydrofor-mylated with 40 atm of 3/4 H2/CO to produce 56% n-heptaldehyde and 24% 2-methylhexaldehyde. Significant isomerization to internal olefins also occurred. 

The chain unit in the thermal and photochemical oxidation of aldehydes by molecular dioxygen consists of two consecutive reactions addition of dioxygen to the acyl radical and abstraction reaction of the acylperoxyl radical with aldehyde. Experiments confirmed that the primary product of the oxidation of aldehyde is the corresponding peroxyacid. Thus, in the oxidation of n-heptaldehyde [10,16,17], acetaldehyde [4,18], benzaldehyde [13,14,18], p-tolualdehyde [19], and other aldehydes, up to 90-95% of the corresponding peroxyacid were detected in the initial stages. In the oxidation of acetaldehyde in acetic acid [20], chain propagation includes not only the reactions of RC (0) with 02 and RC(0)00 with RC(0)H, but also the exchange of radicals with solvent molecules (R = CH3). 

Recently, cross-aldol condensation of benzaldehyde with n-heptaldehyde to give jasminaldehyde (Scheme 13) has been reported a mesoporous molecular sieve Al-MCM-41 with supported MgO was the catalyst. The reactions were carried out in a stirred autoclave reactor with a molar benzaldehyde/heptanal ratio of 10 at 373-448 K (236). The results show that Al-MCM-41 is catalytically active, and its activity is significantly increased by the deposition of MgO (Table V). Increasing the amount of deposited MgO on Al-MCM-41 decreases the surface area but enhances the catalyst basicity. The basicity is well correlated with the catalytic activity, although the selectivity to jasminaldehyde is not the selectivity is essentially independent of temperature, pressure, time of the reaction, and conversion. 

Height equivalent per theoretical plate (H.E.T.P.), 95 n-Heptaldehyde, 251 n-Heptaldoxime, 348 n-Heptane, 238 1-Heptene, 240 n-Heptoic acid, 354, 356 n-Heptoic anhydride, 371, 374 n-Heptyl alcohol, 247, 251 n-Heptylamine, 413, 418 n-Heptyl chloride, 275 n-Heptyl iodide, 288 n-Hexacosane, 938, 941 Hexadecane-1 16-dicarboxylic acid, 938,940... 

The reaction mechanism was explained on the theory that the oxidative attack was through the methyl group, n-octane being converted to n-octaldehyde and this in turn to the next lower aldehyde, with the elimination of carbon monoxide. The degradative action was believed to be repeated step by step, through a nonstop run, to formaldehyde as the final product. n-Heptaldehyde and n-butvraldehyde gave essentially the same products. It was believed the luminescence was due to the chain reaction by which each aldehyde was converted to the next lower aldehyde with the elimination of carbon monoxide. 

In a preliminary consideration of the reaction mechanism, aldehydes and aldols seem to be logical intermediates. It was found that aldehydes undergo the same type of condensation, producing ketones in yields considerably superior to those obtained from the corresponding alcohol. When the aldols of n-butylaldehyde and n-heptaldehyde were subjected to the same reaction conditions, excellent yields of ketones were produced... 

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