Resorcinol reactions

The qualitative SeliwanoflE test for fructose in the urine utilizes the resorcinol reaction (HI). 

CHO —coon. This oxidation can be effected with NaClO if a scavenger is also present to reduce the HOCI formed to HO and Oj. For this piiiposc either 3S% UtO or DNfSO is more useful than sulfamic acid, H-NSC),H. 2-methyl-2-buiene, or resorcinol. Reactions with NaCIOj-H Oj are canted out usually in aqueous acetuniiHle, those with DMSO, in aqueous DMiiO. Yields of >90% can be obtained with aliphatic and aromatic aldehydes as well as the a.fS-enalS- Only chlorinated products are obtained from aldehydes containing isolated double bonds. 

Resorcinol reaction for gangliosides, 281 Respiratory distress syndrome, 551 Response to injury hypothesis and smooth muscle proliferation, 539 Rhamnolipid, 40 Rheological behaviour, 332,361 Rhesus macaque milk, 168 Rhino mutant mouse, 143 Rhizophylyctis rosea, 153 Rhizopus, 151,152,154,478,479, 513 Rhodotorula, 151,152 Rice bran oil, 84,104-06,162 Rice lipoxygenase, 458 Ricin in castor bean, 57 Ricinelaidic acid, 11... 

Sucrose concentrations in the medium and In cal 11 were measured by a colorimetric method using the resorcinol reaction. The assays were performed after acid hydrollsis. 

The use of catechol combined with resorcinol, reaction 5, can be seen in Fig. 13.9. It was noticed that the joining of multiple flakes together as observed for reactions... 

The Hoesch Reaction is employed for the introduction of the - COR group into the aromatic ring of phenol or a phenolic ether, and usually proceeds particularly readily with polyhydric phenols. If an ethereal solution of resorcinol (I)... 

The Reaction has the following limitations (i) a compound that can liberate nitrous acid in acid solution is required (e.g., a metallic nitrite or a nitroso-amine, p. 204). (2) Nitrophenols and />-substituted phenols do not give the test. (3) Among the dihydroxyphenols. only resorcinol gives a satisfactory positive test. 

Fluorescein reaction. Repeat Test i, using however resorcinol instead of phenol. A reddish solution having an intense green fluorescence is produced. 

Fluorescein reaction. Fuse together in a dry test-tube o-i g. of succinimide, O l g. of resorcinol and 2 drops of cone. HjSOi, Cool, add water and then NaOH solution in excess. A green fluorescent solution is obtained. 

Fluorescein reaction. Repeat the above test, but use resorcinol instead of... 

The reaction is particularly facile with di- and tri-hydric phenols. Thus P-resorcyllc acid is readily obtained by passing carbon dioxide through a boiling aqueous solution of the potassium or sodium salt of resorcinol ... 

Paraformaldehyde is used by resin manufacturers seeking low water content or more favorable control of reaction rates. It is often used in making phenol—, urea—, resorcinol—, and melamine—formaldehyde resins. 

Alkali Fusion of /u-Benzenedisulfonic Acid. Even though this process like the previous one is a very ancient one, it is still the main route for the synthesis of resorcinol. It has been described in detail previously and does not seem to have drastically evolved since 1980. It involves the reaction of benzene with sulfuric acid to form y -benzenedisulfonic acid which is then converted to its disulfonate sodium salt by treatment with sodium sulfite. In a second step, this salt is heated to 350°C in the presence of sodium hydroxide yielding the sodium resorcinate and sodium sulfite. 

Resorcinol Derivatives. Aminophenols (qv) are important intermediates for the syntheses of dyes or active molecules for agrochemistry and pharmacy. Syntheses have been described involving resorcinol reacting with amines (91). For these reactions, a number of catalysts have been used / -toluene sulfonic acid (92), zinc chloride (93), zeoHtes and clays (94), and oxides supported on siUca (95). In particular, catalysts performing the condensation of ammonia with resorcinol have been described gadolinium oxide on siUca (96), nickel, or zinc phosphates (97), and iron phosphate (98). 

The synthesis of 2,4-dihydroxyacetophenone [89-84-9] (21) by acylation reactions of resorcinol has been extensively studied. The reaction is performed using acetic anhydride (104), acetyl chloride (105), or acetic acid (106). The esterification of resorcinol by acetic anhydride followed by the isomerization of the diacetate intermediate has also been described in the presence of zinc chloride (107). Alkylation of resorcinol can be carried out using ethers (108), olefins (109), or alcohols (110). The catalysts which are generally used include sulfuric acid, phosphoric and polyphosphoric acids, acidic resins, or aluminum and iron derivatives. 2-Chlororesorcinol [6201-65-1] (22) is obtained by a sulfonation—chloration—desulfonation technique (111). 1,2,4-Trihydroxybenzene [533-73-3] (23) is obtained by hydroxylation of resorcinol using hydrogen peroxide (112) or peracids (113). 

Hydroquinone [123-31 -9] represents a class of commercially important black-and-white chemical reducing agents (see Hydroquinone,RESORCINOL, AND catechol). The following scheme for silver haUde development with hydroquinone shows the quantitative importance of hydrogen ion and haUde ion concentrations on the two half-ceU reactions that describe the silver—hydroquinone redox system ... 

Analytical Methods. A method has been described for gas chromatographic analysis of trichloromethanesulfenyl chloride as well as of other volatile sulfur compounds (62). A method has been recommended for determining small amounts of trichloromethanesulfenyl chloride in air or water on the basis of a color-forming reaction with resorcinol (63). 

Various processes have been disclosed wherein moist soHd sodium pyrosulfite [7681-57-4] is stirred in a steam-heated vessel with sodium carbonate. The exothermic reaction at 80—110°C results in the drying of the product. A lower grade of sodium sulfite is produced commercially in the United States as a by-product of the sulfonation—caustic cleavage route to resorcinol (333). 

Nitro-l-diazo-2-naphthol-4-sulfonic acid prefers the 2-position in spite of the nitro group, and increasing alkalinity favors ortho coupling with diazophenols. 1-Naphthalenesulfamic acid [24344-19-2] (ArNHSO H) and N-nitro-1-naphthylamine [4323-69-7] (ArNHNO ) couple exclusively in the para position. The substitution of resorcinol [108-46-3] and y -phenylenediamine [108-45-2] is compHcated and has been discussed (29,30). The first azo dyes from aniline, eg. Aniline Yellow [60-09-3] (19) (Cl Solvent Yellow 1 Cl 11000) were manufactured in 1861 and Bismark Brown [10114-58-6] (20) (Cl Basic Brown 1 Cl 21000) appeared in 1863. The reaction is as follows ... 

Methylene chloride is one of the more stable of the chlorinated hydrocarbon solvents. Its initial thermal degradation temperature is 120°C in dry air (1). This temperature decreases as the moisture content increases. The reaction produces mainly HCl with trace amounts of phosgene. Decomposition under these conditions can be inhibited by the addition of small quantities (0.0001—1.0%) of phenoHc compounds, eg, phenol, hydroquinone, -cresol, resorcinol, thymol, and 1-naphthol (2). Stabilization may also be effected by the addition of small amounts of amines (3) or a mixture of nitromethane and 1,4-dioxane. The latter diminishes attack on aluminum and inhibits kon-catalyzed reactions of methylene chloride (4). The addition of small amounts of epoxides can also inhibit aluminum reactions catalyzed by iron (5). On prolonged contact with water, methylene chloride hydrolyzes very slowly, forming HCl as the primary product. On prolonged heating with water in a sealed vessel at 140—170°C, methylene chloride yields formaldehyde and hydrochloric acid as shown by the following equation (6). 

Nitrobenzotrichloride is also obtained in high yield with no significant hydrolysis when nitration with a mixture of nitric and sulfuric acids is carried out below 30°C (31). 2,4-Dihydroxybenzophenone [131 -56-6] is formed in 90% yield by the uncatalyzed reaction of benzotrichloride with resorcinol in hydroxyHc solvents (32) or in benzene containing methanol or ethanol (33). Benzophenone derivatives are formed from a variety of aromatic compounds by reaction with benzotrichloride in aqueous or alcohoHc hydrofluoric acid (34). 

Halogenated pyridazines are generally inert as arylating agents in Friedel-Crafts reactions. The only example is the reaction of 3,6-dichloropyridazine with resorcinol and hydroquinone to give 3-aryl-6-chloropyridazines. 

The differentiation of analytical signal in the photometry enables one to use non-specific reagents for the sensitive, selective and express determination of metals in the form of their intensively coloured complexes. The typical representative of such reagents is 4-(2-pyridylazo)-resorcinol (PAR). We have developed the methodics for the determination of some metals in the drinking water which employ the PAR as the photometric reagent and the differentiation of optical density of the mixture of coloured complexes by means of combined multiwave photometry and the specific destmction of the complexes caused by the change of the reaction medium. 

Bromoresorcinol has been prepared by the monobromination of resorcinol monobenzoate and subsequent hydrolysis, from 2-bromo-5-aminophenol by the diazo reaction, by treating resorcinol with dichlorourea and potassium bromide, and by the bromination of 2,4-dihydroxy benzoic acid followed by decarboxylation. The above procedure is based particularly upon the observations of Rice. ... 

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