BENUE, a river of West Africa, the largest and most important affluent of the Niger (q.v.), which it joins after a course of over 800 m. in a general east to west direction from its source in the mountains of Adamawa. Through the Tuburi marshes there is a water connexion between the Benue (Niger) and Shari (Lake Chad) systems.
BEN VENUE, a mountain in south-west Perthshire, Scotland, 10 m. W. of Callander. Its principal peaks are 2393 and 2386 ft. high, and, owing to its position near the south-eastern shore of Loch Katrine, its imposing contour is one of the most familiar features in the scenery of the Trossachs, the mountain itself figuring prominently in The Lady of the Lake. On its northern base, close to the lake, Sir Walter Scott placed the Coir-nan-Uriskin, or “Goblin’s Cave.” Immediately to the south of the cave is the dell called Beal(ach)-nam-Bo, or “Cattle Pass,” through which were driven to the refuge of the Trossachs the herds lifted by the Highland marauders in their excursions to the lands south of Loch Lomond. The pass, though comparatively unvisited, offers the grandest scenery in the district.
BENZALDEHYDE (oil of bitter almonds), C6H5CHO, the simplest representative of the aromatic aldehydes. It was first isolated in 1803 and was the subject of an important investigation by J. v. Liebigin 1837 (Annalen, 1837, 22, p. 1). It occurs naturally in the form of the glucoside amygdalin (C20H27NO11), which is present in bitter almonds, cherries, peaches and the leaves of the cherry laurel; and is obtained from this substance by hydrolysis with dilute acids:
C20H27NO11 + 2H2O = HCN + 2C6H12O6 + C6H5CHO.
It occurs free in bitter almonds, being formed by an enzyme decomposition of amygdalin (q.v.). It may also be prepared by oxidizing benzyl alcohol with concentrated nitric acid; by distilling a mixture of calcium benzoate and calcium formate; by the condensation of chlor-oxalic ester with benzene in the presence of aluminium chloride, the ester of the ketonic acid formed being then hydrolysed and the resulting acid distilled:
C6H6 + Cl·CO·COOC2H5 = C6H5CO·COOC2H5 + HCl,
C6H5CO·COOH = C6H5CHO + CO2;
by the action of anhydrous hydrocyanic acid and hydrochloric acid on benzene, an aldime being formed as an intermediate product:
| C6H6 + HCN + HCl = | C6H5CH : NH·HCl, |
| Benzaldine hydrochloride | |
| C6H5CH : NH·HCl + H2O = NH4Cl + C6H5CHO; | |