AZOIMIDE

azoimide, or hydrazoic acid, n_3h, a compound of nitrogen and hydrogen, first isolated in 1890 by th. curtius (_berichte_, 1890, 23, p. 3023). it is the hydrogen compound corresponding to p. greiss' diazoimino benzene, c_6h_5n_3, which is prepared by the addition of ammonia to diazobenzene perbromide. curtius found that benzoyl glycollic acid gave benzoyl hydrazine with hydrazine hydrate: c_6h_5oco.ch_2cooh + 2n_2h_4.h_2o = h_2o + c_6h_5conh.nh_2 + nh_2.nh.ch_2.cooh. [v.03 p.0083] (ethyl benzoate may be employed instead of benzoyl glycollic acid for this reaction.) this compound gave a nitroso compound with nitrous acid, which changed spontaneously into benzoylazoimide by loss of water: c_6h_5co.nh.nh_2 + hono = h_2o + c_6h_5co.n(no).nh_2. c_6h_5co.n(no).nh_2 = h_2o + c_6h_5co.n_3. the resulting benzoylazoimide is easily hydrolysed by boiling with alcoholic solutions of caustic alkalis, a benzoate of the alkali metal and an alkali salt of the new acid being obtained; the latter is precipitated in crystalline condition on standing. an improved method of preparation was found in the use of hippuric acid, which reacts with hydrazine hydrate to form hippuryl hydrazine, c_6h_5conh.ch_2conh.nh_2, and this substance is converted by nitrous acid into diazo-hippuramide, c_6h_5conh.ch_2.co.nh.n_2.oh, which is hydrolysed by the action of caustic alkalis with the production of salts of hydrazoic acid. to obtain the free acid it is best to dissolve the diazo-hippuramide in dilute soda, warm the solution to ensure the formation of the sodium salt, and distil the resulting liquid with dilute sulphuric acid. the pure acid may be obtained by fractional distillation as a colourless liquid of very unpleasant smell, boiling at 30deg c., and extremely explosive. it is soluble in water, and the solution dissolves many metals (zinc, iron, &c.) with liberation of hydrogen and formation of salts (azoimides, azides or hydrazoates). all the salts are explosive and readily interact with the alkyl iodides. in its properties it shows some analogy to the halogen acids, since it forms difficultly soluble lead, silver and mercurous salts. the metallic salts all crystallize in the anhydrous condition and decompose on heating, leaving a residue of the pure metal. the acid is a "weak" acid, being ionized only to a very slight extent in dilute aqueous solution. e. noelting and e. grandmougin (_berichte_, 1891, 24, p. 2546) obtained azoimide from dinitraniline, c_6h_3(no_2)_2.nh_2, by diazotization and conversion of the diazo compound into the perbromide, (no_2)_2c_6h_3.n_2.br_3. this compound is then decomposed by ammonia, dinitrophenylhydrazoate being formed, which on hydrolysis with alcoholic potash gives potassium hydrazoate (azide) and dinitrophenol. the solution is then acidified and distilled, when azoimide passes over. somewhat later, they found that it could be prepared from diazobenzene imide, provided a nitro group were present in the ortho or para position to the diazo group. the para-nitro compound is dropped slowly into a cold solution of one part of caustic potash in ten parts of absolute alcohol; the solution becomes dark red in colour and is then warmed for two days on the water bath. after the greater portion of the alcohol has distilled off, the solution is acidified with sulphuric acid and the azoimide distilled over. the yield obtained is only about 40% of that required by theory, on account of secondary reactions taking place. ortho-nitro-diazobenzene imide only yields 30%. w. wislicenus (_berichte_, 1892, 25, p. 2084) has prepared the sodium salt by passing nitrous oxide over sodamide at high temperatures. the acid can also be obtained by the action of nitrous acid on hydrazine sulphate; by the oxidation of hydrazine by hydrogen peroxide and sulphuric acid (a. w. browne, _j. amer. chem. soc._, 1905, 25, p. 251), or by ammonium metavanadate (a. w. browne and f. f. shetterly, _abst. j.c.s._, 1907, ii. p. 863). _ammonium azoimide_, n_3.nh_4, may be prepared by boiling diazohippuramide with alcoholic ammonia, until no more ammonia escapes, the following reaction taking place: c_6h_5co.nhch_2conh.n_2.oh + 2nh_3 = n_3.nh_4 + h_2o + c_6h_5co.nh.ch_2.co.nh_2. the liquid is then allowed to stand for twelve hours, and the clear alcoholic solution is decanted from the precipitated hippuramide. to the alcoholic solution, four times its volume of ether is added, when the ammonium salt is precipitated. it is then filtered, washed with ether, and air-dried. the salt is readily soluble in water, and is only feebly alkaline. it is extremely explosive. _hydrazine azoimide_, n_5h_5, is also known. _chloroazoimide_, cl.n_3, the chloride corresponding to azoimide, was obtained by f. raschig (_ber._, 1908, 41, p. 4194) as a highly explosive colourless gas on acidifying a mixture of sodium azide and hypochlorite with acetic or boric acid. azores (_acores_), or western islands, an archipelago in the atlantic ocean, belonging to the kingdom of portugal. pop. (1900) 256,291; area, 922 sq. m. the azores extend in an oblique line from n.w. to s.e., between 36deg 55' and 39deg 55' n., and between 25deg and 31deg 16' w. they are divided into three widely severed groups, rising from a depth of more than 2-1/2 m. the south-eastern group consists of st michael's (sao miguel) and st mary (santa maria), with formigas; the central, of fayal (faial), pico, st george (sao jorge), terceira and graciosa; the north-western, of flores and corvo. [illustration] the nearest continental land is cape da roca on the portuguese coast, which lies 830 m. e. of st michael's; while cape cantin, the nearest point on the african mainland, is more than 900 m. distant, and cape race in newfoundland, the nearest american headland, is more than 1000 m. thus the azores are the farthest from any continent of all the island groups in the atlantic; but they are usually regarded as belonging to europe, as their climate and flora are european in character. _physical description._--the aspect of all the islands is very similar in general characteristics, presenting an elevated and [v.03 p.0084] undulating outline, with little or no tableland, and rising into peaks, of which the lowest, that of corvo, is 350 ft., and the highest that of pico, 7612 ft. above sea-level. the lines of sea-coast are, with few exceptions, high and precipitous, with bases of accumulated masses of fallen rock, in which open bays, or scarcely more enclosed inlets, form the harbours of the trading towns. the volcanic character of the whole archipelago is obvious, and has been abundantly confirmed by the numerous earthquakes and eruptions which have taken place since its discovery. basalt and scoria are the chief erupted materials. hitherto flores, corvo and graciosa have been quite exempt, and fayal has only suffered from one eruption (1672). the centre of activity has for the most part been st michael's, while the neighbouring island of st mary has altogether escaped. in 1444-1445 there was a great eruption at st michael's, of which, however, the accounts that have been preserved exaggerate the importance. in 1522 the town of villa franca, at that time the capital of the island, was buried, with all its 6000 inhabitants, during a violent convulsion. in 1572 an eruption took place in pico; in 1580 st george was the scene of numerous outbursts; and in 1614 a little town in terceira was destroyed. in 1630, 1652, 1656, 1755, 1852, &c., st michael's was visited with successive eruptions and earthquakes, several of them of great violence. on various occasions, as in 1638, 1720, 1811 and 1867, subterranean eruptions have taken place, which have sometimes been accompanied by the appearance of temporary islands. of these the most remarkable was thrown up in june 1811, about half a league from the western extremity of st michael's. it was called sabrina by the commander of the british man-of-war of that name, who witnessed the phenomenon. _climate._--the climate is particularly temperate, but the extremes of sensible heat and cold are increased by the humidity. the range of the thermometer is from 45deg fahr., the lowest known extreme, or 48deg, the ordinary lowest extreme of january, to 82deg, the ordinary, or 86deg, the highest known extreme of july, near the level of the sea. between these two points (both taken in the shade) there is from month to month a pretty regular gradation of increase or decrease, amounting to somewhat less than four degrees. in winter the prevailing winds are from the north-west, west and south; in summer the most frequent are the north, north-east and east. the weather is often extremely stormy, and the winds from the west and south-west render the navigation of the coasts very dangerous. _fauna._--the mammalia of the azores are limited to the rabbit, weasel, ferret, rat (brown and black), mouse and bat, in addition to domestic animals. the game includes the woodcock, red partridge (introduced in the 16th century), quail and snipe. owing to the damage inflicted on the crops by the multitude of blackbirds, bullfinches, chaffinches and green canaries, a reward was formerly paid for the destruction of birds in st michael's, and it is said that over 400,000 were destroyed in several successive years between 1875 and 1885. there are valuable fisheries of tunny, mullet and bonito. the porpoise, dolphin and whale are also common. whale-fishing is a profitable industry, with its headquarters at fayal, whence the sperm-oil is exported. eels are found in the rivers. the only indigenous reptile is the lizard. fresh-water molluscs are unknown, and near the coast the marine fauna is not rich; but terrestrial molluscs abound, several species being peculiar to the azores. _flora._--the general character of the flora is decidedly european, no fewer than 400 out of the 478 species generally considered as indigenous belonging likewise to that continent, while only four are found in america, and forty are peculiar to the archipelago. vegetation in most of the islands is remarkably rich, especially in grasses, mosses, and ferns, heath, juniper, and a variety of shrubs. of tall-growing trees there was, till the 19th century, an almost total lack; but the bordeaux pine, european poplar, african palm-tree, australian eucalyptus, chestnut, tulip-tree, elm, oak, and many others, were then successfully introduced. the orange, apricot, banana, lemon, citron, japanese medlar, and pomegranate are the common fruits, and various other varieties are more or less cultivated. at one time much attention was given to the growing of sugar-cane, but it has now for the most part been abandoned. the culture of indigo, introduced in the 16th century, also belongs to the past. a kind of fern (_dicksonia culcita_), called by the natives _cabellinho_, furnishes a silky material for the stuffing of mattresses and is exported to brazil and portugal. _population._--the inhabitants of the islands are mostly of portuguese origin, with a well-marked strain of moorish and flemish blood. there is a high birth-rate and a low average of infant mortality. a large proportion of the poorer classes, especially among the older men and women, are totally illiterate, but education tends to spread more rapidly than in portugal itself, owing to the custom of sending children to the united states, where they are taught in the state schools. negroes, mulattoes, english, scottish and irish immigrants are present in considerable numbers, especially in fayal and st michael's. the total number of resident foreigners in 1900 was 1490. _government._--the azores are subdivided into three administrative districts named after their chief towns, _i.e._ ponta delgada, the capital of st michael's; angra, or angra do heroismo, the capital of terceira; and horta, the capital of fayal. st michael's and st mary are included in the district of ponta delgada; terceira, st george and graciosa, in that of angra; pico, fayal, flores and corvo, in that of horta. four members are returned by ponta delgada to the parliament in lisbon, while each of the other districts returns two members. roman catholicism is the creed of the majority, and angra is an episcopal see. for purposes of military administration the islands form two commands, with their respective headquarters at angra and ponta delgada. besides the frequent and regular services of mails which connect the azores with portugal and other countries, there is a cable from lisbon to villa franca do campo, in st michael's, and thence to pico, fayal, st george and graciosa. fayal is connected with waterville, in ireland, by a cable laid in 1901. at angra and ponta delgada there are meteorological stations. the principal seaports are angra (pop. 1900, 10,788), ponta delgada (17,620), and horta (6574). _trade._--the trade of the azores, long a portuguese monopoly, is now to a great extent shared by the united kingdom and germany, and is chiefly carried in british vessels. textiles are imported from portugal; coal from great britain; sugar from germany, madeira and the united states; stationery, hardware, chemicals, paints, oils, &c., from the united kingdom and germany. the exports consist chiefly of fruit, wine, natural mineral waters and provisions. the trade in pineapples is especially important. no fewer than 940,000 pineapples were exported in 1902 and 1903, going in almost equal quantities to london and hamburg. the fruit is raised under glass. pottery, cotton fabrics, spirits, straw hats and tea are produced in the district of ponta delgada; linen and woollen goods, cheese, butter, soap, bricks and tiles, in that of angra; baskets, mats, and various ornamental articles made from straw, osier, and the pith of dried fig-wood, in that of horta. the largest and most populous of the azores is st michael's, which has an area of 297 sq. m., and in 1900 had 121,340 inhabitants. graciosa (pop. 8385; area, 17 sq. m.) and st george (16,177; 40 sq. m.) form part of the central group. graciosa is noteworthy for the beauty of its scenery. its chief towns are santa cruz de graciosa (2185) and guadalupe (2717). the chief towns of st george are ribeira seca (2817) and velas (2009). _history._--it does not appear that the ancient greeks and romans had any knowledge of the azores, but from the number of carthaginian coins discovered in corvo it has been supposed that the islands must have been visited by that adventurous people. the arabian geographers, edrisi in the 12th century, and ibn-al-wardi in the 14th, describe, after the canaries, nine other islands in the western ocean, which are in all probability the azores. this identification is supported by various considerations. the number of islands is the same; the climate under which they are placed by the arabians makes them north of the canaries; and special mention is made of the hawks or buzzards, which were sufficiently numerous at a later period to [v.03 p.0085] give rise to the present name (port. _acor_, a hawk). the arabian writers represent them as having been populous, and as having contained cities of some magnitude; but they state that the inhabitants had been greatly reduced by intestine warfare. the azores are first found distinctly marked in a map of 1351, the southern group being named the goat islands (_cabreras_); the middle group, the wind or dove islands (_de ventura sive de columbis_); and the western, the brazil island (_de brazi_)--the word brazil at that time being employed for any red dye-stuff. in a catalan map of the year 1375 corvo is found as _corvi marini_, and flores as _li conigi_; while st george is already designated _san zorze_. it has been conjectured that the discoverers were genoese, but of this there is not sufficient evidence. it is plain, however, that the so-called flemish discovery by van der berg is only worthy of the name in a very secondary sense. according to the usual account, he was driven on the islands in 1432, and the news excited considerable interest at the court of lisbon. the navigator, gonzalo velho cabral--not to be confounded with his greater namesake, pedro alvarez cabral--was sent to prosecute the discovery. another version relates that prince henry the navigator of portugal had in his possession a map in which the islands were laid down, and that he sent out cabral through confidence in its accuracy. the map had been presented to him by his brother, dom pedro, who had travelled as far as babylon. be this as it may, cabral reached the island, which he named _santa maria_, in 1432, and in 1444 took possession of st michael's. the other islands were all discovered by 1457. colonization had meanwhile been going on prosperously; and in 1466 fayal was presented by alphonso v. to his aunt, isabella, the duchess of burgundy. an influx of flemish settlers followed, and the islands became known for a time as the flemish islands. from 1580 to 1640 they were subject, like the rest of the portuguese kingdom, to spain. at that time the azores were the grand rendezvous for the fleets on their voyage home from the indies; and hence they became a theatre of that maritime warfare which was carried on by the english under queen elizabeth against the peninsular powers. one such expedition, which took place in 1591, led to the famous sea-fight off flores, between the english ship "revenge," commanded by sir richard grenville, and a spanish fleet of fifty-three vessels. under the active administration of the marquis de pombal (1690-1782), considerable efforts were made for the improvement of the azores, but the stupid and bigoted government which followed rather tended to destroy these benefits. towards the beginning of the 19th century, the possession of the islands, was contested by the claimants for the crown of portugal. the adherents of the constitution, who supported against miguel the rights of maria (ii.) da gloria, obtained possession of terceira in 1829, where they succeeded in maintaining themselves, and after various struggles, queen maria's authority was established over all the islands. she resided at angra from 1830 to 1833. for a general account of the islands, see _the azores_, by w. f. walker (london, 1886), and _madeira and the canary islands, with the azores_, by a. s. brown (london, 1901). on the fauna and flora of the islands, the following books by h. drouet are useful:--_elements de la faune acoreenne_ (paris, 1861); _mollusques marins des iles acores_ (1858), _lettres acoreennes_ (1862), and _catalogue de la flore des iles acores, precede de l'itineraire d'une voyage dans cet archipel_ (1866). the progress of azorian commerce is best shown in the british and american consular reports. for history, see _la conquista de las azores en 1583_, by c. fernandez duro (madrid, 1886), and _histoire de la decouverte des iles azores et de l'origine de leur denomination d'iles flamandes_, by j. mees (ghent, 1901).