Hydrogenation, apparatus for high

Fig. 3 Apparatus for high pressure hydrogenation. A, autoclave B, hydrogen inlet valve C, pressure release valve D, pressure gauge E, heating mantle F rocking device.

A solution of 24 g. (0.6 mole) of sodium hydroxide, 100 ml. of water, and 55 g. (0.5 mole) of resorcinol is placed in an apparatus for high-pressure hydrogenation together with 10 g. of reduced... 

A solution of 108 g. (0.5 inole) of diethyl ethoxymethylene-malonate (Note 1) in 100 ml. of commercial absolute alcohol is placed in an apparatus for high-pressure hydrogenation together with 10 g. of Raney nickel catalyst (Note 2). The pressure in the bomb is raised to 1000-1500 lb. with hydrogen, and the temperature is adjusted to 45° (Note 3). The bomb is shaken, and the reaction is allowed to proceed for 12-20 hours, during which time 0.5 mole of hydrogen is absorbed. 

Apparatus for hydrogenation at atmospheric pressure, 470-473 for high pressure hydrogenation, 868-870... 

One hundred and six grams (i mole) of benzaldehyde (Note i) and 107 g. (1 mole) of m-toluidine are mixed in a suitable flask the temperature rises to about 6o° (Notes 2 and 3). The mixture is cooled below 35° in cold water, 200 cc. of ether is added, and the solution is placed in the steel reaction vessel of a high-pressure hydrogenation apparatus.1,2 Eight to ten grams of Raney nickel catalyst (p. 15) is added, the bomb is closed, and hydrogen is admitted up to 1000 lb. pressure (Note 4). The bomb is shaken continuously at room temperature for fifteen minutes (Note 5). The contents are removed, and the bomb is washed out with two 200-cc. portions of ether. After the catalyst has been separated by filtration (Note 6), the ether is removed by distillation and the product is distilled from a modified Claisen flask (Note 7). After a small fore-run the A-benzyl-m-toluidine boils at i53-i57°/4 mm. 3iS-3i7°/76o mm. The yield is 175-185 g. (89-94 per cent of the theoretical amount) (Notes 8 and 9). 

A solution of 3,4-dihydro-6,7-dimethoxy-l-methylisoquinoline hydrochloride (58.4 g, 0.24 m) in 1 liter of methanol and 5% Pd/C (5 g) were combined under nitrogen in a pressure bottle and the mixture hydrogenated at 40 psi and ambient temperature on a Parr apparatus for 18 hr. The catalyst was removed by filtration and the solvent evaporated. The residue was dissolved in H20 (1 liter), basified to pH 11 with 50% NaOH and extracted with CHCI3, (3x300 ml). The extracts were dried over MgS04 and evaporated to dryness (aspirator, then high vacuum) to give l,2,3,4-tetrahydro-6,7-dimethoxy-l-methylisoquinoline, 35.2 g (70% yield). 

Zhirov, A.S., Solovey, V.V., Plichko, V.S., Makarov A.A. An apparatus for the production of high-pressure hydrogen and oxygen // Patent 29853F, Ukraine, 1998... 

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