Yellow substances

Mcrcuryill) iodide, HgL. Scarlet (to 126 C) or yellow substance (HgC L solution plus KI or Hg plus I2)- Forms complex iodides with excess iodide (Nessler s reagent). 

Diversine, C2oH2,05N Pamsinomenine). This base was obtained by Kondo, Ochiai and Nakajima as an amorphous, yellow substance, m.p. 80-93°, [a]n ° + 6-98°. It reduces solutions of gold or silver salts. The hydrochloride is amorphous, m.p. 135-140° (dec.), as is also the methio-dide. The alkaloid contains two methoxyl groups and one methylimino-group, and with benzoic anhydride yields a mixture of mono- and dibenzoyl derivatives. For another diversine, see p. 350. 

Aristolochic Acid. Rosenmund and Reichstein prepared their material from roots and rhizomes of A. Sipho. It has the formula Cj HjiO N, m.p. 275° (dec.), and forms a methyl ester, m.p. 280° (dec.), [a]n 0°, which is difficult to saponify and on. hydrogenation gives a bright yellow substance, m.p. 312°, which forms a diacetyl... 

Riboflavin was first isolated from whey in 1879 by Blyth, and the structure was determined by Kuhn and coworkers in 1933. For the structure determination, this group isolated 30 mg of pure riboflavin from the whites of about 10,000 eggs. The discovery of the actions of riboflavin in biological systems arose from the work of Otto Warburg in Germany and Hugo Theorell in Sweden, both of whom identified yellow substances bound to a yeast enzyme involved in the oxidation of pyridine nucleotides. Theorell showed that riboflavin 5 -phosphate was the source of the yellow color in this old yellow enzyme. By 1938, Warburg had identified FAD, the second common form of riboflavin, as the coenzyme in D-amino acid oxidase, another yellow protein. Riboflavin deficiencies are not at all common. Humans require only about 2 mg per day, and the vitamin is prevalent in many foods. This vitamin... 

With sodium nitrate, pure sodium (or in liquid ammonia) gives rise to an explosive yellow substance, which may be the same hyponitrite as the one above. 

The yellow substance was studied under deep space conditions. After being subjected to UV-irradiation for about four months, it changed colour to brown, possibly due to enrichment in carbon or carbon-containing compounds. IR analysis showed that the new brown substance showed the same absorption lines as those observed in interstellar dust. A special IR study carried out at Stanford University indicated that the brown substance contained many PAHs. 

Under this heading are discussed both the naturally occurring fluorescent material and the yellow substances which give coastal waters their generally greenish colour. It is usually considered that these two categories are the same, or at least overlap almost entirely. 

Yellow Rain A lethal yellow substance thought to have been dispersed aerially as a warfare agent in Southeast Asia and Afghanistan the lethal component is though to have been a trichothecene mycotoxin that was reported to produce severe nausea and vomiting, disturbances in the central nervous system. Fever, chills, and abnormally low blood pressure with a case mortality of approximately 50 percent. 

One of these reactions, namely the oxidation of the cuprous complexes of 2-thienyl and 2- and 3-substituted thienylacetylenes, was studied in this laboratory (80). It has been found that this reaction proceeds in an analogous manner to that in other aromatic series. The yields of the corresponding diacetylenic compounds were high and depended on the oxidizing agent applied. The cuprous complexes of 2-thienylacetylene and 2- and 3-substituted thienylacetylenes are bright yellow substances, stable at room temperature. They could be readily utilized for the determination of thienylacetylenes as well as for cuprous ions. 

Initial ring-opening reactions of thiazetidines can directly lead to polymeric material (Eq. 71). The polymer lAl is a yellow substance with a net formula of (H2S2C2N2) . 

In 1803 Klaproth and independently Berzelius found at an abandoned iron ore mine at Bcustnas, likewise in Sweden, a mineral v ch received the name B2istnasite. In this mineral the researchers found new eeurths v ch they named "ochroite ecu hs" because upon heating of the mineral a yellow substance resulted. They gave the assumed metal the name cerium after the small planet Ceres. 

The young assistant concluded that there were only two possible explanations The yellow substance must either be a compound of chlorine with some constituent of the lye, or it must be a new element just liberated from one of its compounds by the chlorine, which had replaced it. Balard at first favored the first hypothesis and thought that he had an iodide of chlorine, but, when all attempts to decompose the new substance failed, he concluded that his second explanation must be the correct one and that the new element must be similar to iodine and chlorine (28). 

Ksilil (Russ, Xylitej in Fr, Ksylit in Polish, TNX). A term given to commercial Trinitro-xylene (TNX) which consists chiefly of the trinitro derivatives, of meta-, with some ortho-and para-xylenes. It is a greyish-yellow substance prepd by the nitration of commercial xylene by mixed nitric-sulfuric acid. It is insol in w. Ksilil is slightly more, sensitive to initiation, and about as sensitive to impact and bullet test as TNT. It was used in composite expls as a partial substitute for TNT Refs 1) PATR 2145 (1955), p Rus 10-L 2) Gorst (1957), 100 3) Urbanski 1 (1964),... 

Ammino-ferrous Sulphate.—When hydrated ferrous sulphate is heated to 115° C. it loses six molecules of water, leaving a pale yellow substance, the monohydrate, FeS04.H20. This salt readily absorbs ammonia gas, becoming reddish brown in colour with formation of pentammino-ferrous sulphate, [Fe(NH3)5]S04.H20. In vacuo the pent-ammine loses two molecules of ammonia and is converted into the diammine, [Fe(NH3)2]S04.H20. The diammine, on exposure to more ammonia, gives a triammino-derivative, [Fe(NH3)3]S04.H20, but no further absorption of ammonia takes place.2... 

More complex salts are also known belonging to the series. For instance, if a solution of nitro-pentammino-cobaltic chloride be treated with an aqueous solution of sodium cobaltic nitrite, Na3Co(N02)6, a yellowish-brown crystalline precipitate of nitro-pentammino-cobaltic cobalti-nitrite, [Co(NH3)5(N02)]3[Co(N02)6]2, is formed. Also the corresponding ferrocyanicle may be prepared by treating nitro-pentammino-salts with potassium ferrocyanide. The compound obtained is a reddish-yellow substance of composition [Co(NH3)5(NO,)], [Fe(CN )6].6H20. 

Di-iodo-diammino-palladium, [Pd(NH3)2I2].—Two compounds are known having the same composition, one yellow, the other red. Both these substances have been described as the di-iodo-eompound. It is probable that the yellow substance is the true iodo-derivative, and the other the iodo-palladite of the tetrammino-compound. 

Emmens Acid. A yellow substance prepd in 1888 in the USA and in England by Dr S. 

When an alkali thiocyanate is warmed with moderately concentrated sulphuric or hydrochloric acid, a yellow solid separates and carbonyl sulphide gas is evolved, which burns with a pale sulphurous flame. The yellow substance contains isoperthiocyanic acid, formed, together with hydrocyanic acid, according to the reaction ... 

Phosphorus Chloroselenide, PSeCl3.—By treating phosphorus pentachloride with selenium tetrachloride, phosphorus chloroselenide has been obtained as a yellow substance which becomes red on heating.7... 

Vanadyl Difluoride, VOF2, is prepared by the action of anhydrous hydrogen fluoride on vanadyl dibromide, VOBr2. It is a yellow substance. Density at 19° C., 3-3956.s A hydrated vanadyl difluoride, V0F2.a, H20, is obtained as microscopic blue crystals when hypovanadic oxide, V02, is dissolved in excess of hydrofluoric acid and the solution concentrated slowly over sulphuric acid.1 The following double salts have been prepared, all of which are crystalline and fairly stable —5... 

When a solution containing sodium orthovanadate and stannous chloride is carefully neutralised with caustic soda, an amorphous yellow substance is obtained which has the composition... 

Indium Metavanadate, In(V03)3.2H20, is a yellow substance produced by the action of sodium metavanadate on indium chloride solution.12... 

The yellow substance produced with more concentrated solutions is silver nitrato-arsenide,3 Ag3As.3AgN03, which is formed thus ... 

The crystals dissolve in carbon disulphide and ebullioscopic measurements indicate1 that the molecular formula is As2I4 they also dissolve in ether, alcohol and chloroform. When exposed to air, these solutions darken in colour owing to the formation of the triiodide, and the diiodide cannot be recovered bv evaporation owing to complete decomposition. Boiling acetic anhydride also dissolves the crystals but, on cooling, a yellow substance which appears to contain a derivative of the triiodide separates. The diiodide is also decomposed by pyridine with separation of arsenic, the triiodide being found in solution. 

Ammonia is slowly absorbed by the triiodide and a voluminous yellow substance is produced8 which, if kept over sulphuric acid, loses ammonia until the composition corresponds with the tetrammino-triiodide, AsIg.ANHg. At 0° C. more ammonia can be absorbed to yield the dodecammino-compound, AsI3.12NH3. If ammonia is passed into a solution of the triiodide in benzene or ether, a voluminous white precipitate, of composition 2AsI3.9NH3, is formed.8 The existence of these ammines as definite compounds has not been established.10 With phosphine, arsenic phosphide is produced ... 

Ferric Pyroarsenite, FCj(As205)3.7HoO, has been described 7 as a yellow substance obtained by adding ferric hydroxide to a hot saturated solution of arsenious oxide in concentrated sodium hydroxide. On cooling, excess of arsenious oxide separates, and after keeping for 24 hours a yellow precipitate of the above composition is formed. The existence of the pyroarsenite has not been confirmed, however. 

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