1. Heptaldehyde is contained in rose oil as well as perilla oil. It was first manufactured by pyrolysis of castor oil in 1845. Castor oil includes ricinoleic acid glyceride, and also in the presence of solid caustic potassium, it is alcoholylated with methanol at area temperature to obtain ricinoleic acid methyl ester. The response item was acidified with sulfuric acid, the methanol was distilled off, the glycerin layer was divided and also washed with water to get methyl ricinoleic acid. Split it in a pyrolysis heater at 450-500 ° C and 0.05-0.07 MPa to obtain methyl undecylenate and also Heptaldehyde. Separate the pyrolysis item from the material, and carry out vacuum correction to get methyl undecylenate (the raw product of undecylenic acid, a vital intermediate of fragrances) and heptanal. Heptaldehyde was cleansed with sodium bisulfite and also sodium carbonate to obtain a pure product with a content ≥ 88%, and also regarding 5.5 t of castor oil was eaten per ton of Heptaldehyde.
2. Acquired by oxidation of heptanol or cracking of castor oil.
3. Prep work technique:
Include 500mL of anhydrous pyridine ① right into a completely dry reaction flask furnished with a stirrer, a thermostat, as well as a drying tube, cool in an ice-water bathroom to 15 ° C, include 68 g (0.56 mol) of anhydrous chromium trichloride ② in batches over 15 minutes while mixing, Keep in mind that the temperature level of the response solution does not go beyond 20 ° C when adding. A dark yellow flocculent precipitate sped up out during the addition, as well as the viscosity of the combination increased. After the addition, continue to mix and also rise to room temperature, the viscosity decreases within 1h, and the yellow product is dark red crystal. Let stand, pour off pyridine, as well as wash 3 times with anhydrous oil. Filtrate with suction, laundry with petroleum ether, and also dry in vacuo to acquire 150-160 g of chromium trioxide-pyridine, which is stored in a brownish bottle at 0 ° C. Heptaldehyde (1 ): In a reaction flask outfitted with a stirrer, add 650 mL of anhydrous dichloromethane, add 77.5 g (0.3 mol) of chromium trioxide-pyridine facility at space temperature level under stirring, and then include n-heptanol (2) each time 5.8 g (0.05 mol), after regarding 20min, pour out the supernatant from the insoluble brown jelly, and also wash the insoluble deposit three times with ether. The dichloromethane as well as ether layers were combined, cleaned successively with 5% salt hydroxide, 5% hydrochloric acid, saturated sodium carbonate, and also saturated brine, as well as dried out over anhydrous magnesium sulfate. After distilling off the solvent, distill under lowered stress, accumulate the fraction at 80-84 ° C/8.65 kPa, and also get 4-4.8 g of Heptaldehyde ③( 1 ), with a return of 70% -84%.
Note: ① Dry with solid potassium hydroxide as well as re-steam as soon as before usage. ② Dry chromium trioxide in a vacuum desiccator full of phosphorus pentoxide before usage. ③ This is just one of the techniques for preparing aldehydes from alcohols. The general approach for preparing aldehydes from alcohols using chromium trioxide-pyridine facilities as an oxidant is as adheres to: initial prepare 5% chromium trioxide-pyridine in anhydrous dichloromethane service (dark red), to ensure that the molar proportion of the complex to alcohol is 6:1. The excess of the oxidizing agent is to totally oxidize the alcohol to the aldehyde. Add the alcohol to the above dark red solution at once under stirring at area temperature level, and also the key or additional alcohol without steric limitation can be completely reacted within 5-15 mins at 25 ° C, as well as the brown-black chromium trioxide-pyridine decrease product is sped up at the same time. The supernatant was decanted, and also the precipitate was completely cleaned with dichloromethane. Incorporate the dichloromethane option, laundry with water down hydrochloric acid, sodium bicarbonate, water, etc in order to remove pyridine as well as chromium salts, or straight filter with filter aid, or separate with a chromatographic column, and distill off the solvent to obtain the corresponding item.
4. Prep work method:
In a reaction flask outfitted with a stirrer and also a thermometer, add a solution of 11g of silver p-toluenesulfonate ① liquified in 100mL of acetonitrile, trendy to 0-5 ° C, add 7.0 g (31mmol) of 1-iodoheptane (2 ), and stirred overnight at space temperature in the dark. The catalyst was poured into ice water and extracted with ether. The ether layer was dried as well as solvent gotten rid of to provide an oil. Include 20 g of sodium bicarbonate as well as 150 mL of DMSO into an additional reaction flask, and impact nitrogen into it to maintain bubbling. Include the above oil and also warmth to 150 ° C (often smoking cigarettes). After 3 minutes, it was quickly cooled down to space temperature. The resulting aldehyde was reacted with 2,4-dinitrophenylhydrazine to generate the matching phenylhydrazone, and also 6.9 g of phenylhydrazone was gotten, with a yield of 70%, mp106 ～ 107 ℃. The typical samples are mixed, and also the melting point of the combination continues to be unchanged.
Keep in mind: ① Its preparation approach is: include equimolar silver oxide and p-toluenesulfonic acid monohydrate right into acetonitrile, mix for half an hour at night, and also filter. Acetonitrile was vaporized, dried at 65 ° C and also set aside.
