Periodic Acid reaction

Gas chromatography liquid chromatography periodic acid reaction and titration Extraction Titration... 

Ozone is formed in certain chemical reactions, including the action of fluorine on water (p. 323) and the thermal decomposition ofiodic(VII) (periodic) acid. It is also formed when dilute (about 1 M) sulphuric acid is electrolysed at high current density at low temperatures the oxygen evolved at the anode can contain as much as 30% ozone. 

The "periodic acids and periodates are powerful oxidising agents and they will oxidise manganese to manganate(VlI). a reaction used to determine small quantities of manganese in steel. 

An alternative procedure for the above test is as follows. Mix 2-3 ml. of 2 per cent, aqueous paraperiodic acid solution with 1 drop of dilute sulphuric acid (ca. 2 5N) and add 20-30 mg. of the compound. Shake the mixture for 5 minutes, and then pass sulphur dioxide through the solution until it acquires a pale yellow colour (to remove the excess of periodic acid and also iodic acid formed in the reaction). Add 1-2 ml. of Schiff s reagent (Section 111,70) the production of a violet colour constitutes a positive test. 

The polyhydric alcohols of Solubility Group II are liquids of relatively high boiling point and may be detected inter alia by the reactions already described for Alcohols (see 6). Compounds containing two hydroxyl groups attached to adjacent carbon atoms (1 2-glyeols), a-hydroxy aldehydes and ketones, and 1 2-diketones may be identified by the periodic acid test, given in reaction 9. 

Periodic acid has a selective oxidising action upon compounds having two hydroxyl groups or a hydroxyl and an amino group attached to adjacent carbon atoms and is characterised by the cleavage of the carbon - carbon bond (Malaprade reaction) ... 

A reaction characteristic of vicinal diols is their oxidative cleavage on treatment with periodic acid (HIO4) The carbon-carbon bond of the vicinal diol unit is broken and two carbonyl groups result Periodic acid is reduced to iodic acid (HIO3)... 

Cyclic diols give dicarbonyl compounds The reactions are faster when the hydroxyl groups are cis than when they are trans but both stereoisomers are oxidized by periodic acid... 

Periodic acid oxidation (Section 15 12) finds extensive use as an analytical method m carbohydrate chemistry Structural information is obtained by measuring the number of equivalents of periodic acid that react with a given compound and by identifying the reaction products A vicinal diol consumes one equivalent of penodate and is cleaved to two carbonyl compounds... 

Oxidation. Monochloroacetic acid [79-11-8] may be synthesized by the reaction of ethylene chlorohydrin with nitric acid [7697-37-2]. Yields of greater than 90% are reported (41). >Beta-chlorolactic acid (3-chloro-2-hydroxypropanoic acid) [1713-85-5] is produced by the reaction of nitric acid with glycerol monochlorohydrin (42). Periodic acid [10450-60-9] and glycerol monochlorohydfin gives chloroacetaldehyde [107-20-0] ia 50% yield (43). 

Perchloric acid (79% HCIO4/CH2CI2, 0°, 1 h 25°, 3 h, 87% yield) and periodic acid (aq. dioxane, 3 h, quant, yield) cleave 1,3-dioxolanes the latter drives the reaction to completion by oxidation of the ethylene glycol that forms. Yields are substantially higher from cleavage with perchloric acid (3 AHCIO4/THF, 25°, 3 h, 80% yield) than with hydrochloric acid (HCl/HOAc, 65% yield)... 

To the epoxide dissolved in a minimal amount of chloroform or ether is added a corresponding solution of freshly prepared thiocyanic acid (20 fold excess) as described above (acetic acid has also been used as solvent). The resulting solution is allowed to stand at least 70 hr at room temperature. (Some workers have protected the reaction mixture from light during this period). The reaction mixture is worked up by washing first with a 10% solution of sodium carbonate, sodium bicarbonate or potassium bicarbonate, and then water. The remaining ether extract is dried (Na2S04) and evaporated under vacuum. The crude thiocyanatohydrin is crystallized from an appropriate solvent or treated with methanesulfonyl chloride s (see below). 

Can you remember what reaction of an alkene would give the same products as the periodic acid cleavage shown here ... 

The use of periodic acid oxidation in structure determination can be illustrated by a case in which a previously unknown methyl glycoside was obtained by the reaction of D-arabinose with methanol and hydrogen chloride. The size of the ring was identified as five-membered because only one mole of periodic acid was consumed per mole of glycoside and no formic acid was produced. Were the ring six-membered, two moles of periodic acid would be required per mole of glycoside and one mole of formic acid would be produced. 

The oxidative cleavage of the central carbon-carbon bond in a vicinal diol 1, by reaction with lead tetraacetate or periodic acid, yields two carbonyl compounds 2 and 3 as products. 

The cleavage of 1,2-diols 1 by periodic acid is associated with the name of the French chemist Malaprade. The reaction mechanism is related to that outlined above, and is likely to involve a five-membered ring periodate ester intermediate 7 ... 

Somewhat milder oxidative conditions lead to loss of but one carbon. Periodic acid cleavage of the side chain in 65, leads to the so-called etio acid (66). Reaction with propionic anhydride leads to acylation of the 17-hydroxyl group (67). Possibilities for neighboring group participation severely limit the methods available for activating the acid for esterification. Best results seemed to have been obtained by use of a mixed anhydride from treatment with diphenyl chloro-... 

About 20 grams of diamino diphenyl sulfone is dissolved in about 500 cc of ethyl alcohol (3A made up of 5 parts methyl alcohol and 100 parts of ethyl alcohol) by placing the ingredients in a flask provided with a reflux condenser and warming over a water bath. About 24 grams of pure grade, very finely powdered (40 to 60 mesh) sodium formaldehyde sulfoxylate Is then rapidly added to the alcohol solution of diamino diphenyl sulfone and the mixture refluxed in the usual manner. It was found that the mixture should be refluxed for a total of 5 hours and that a precipitate starts to form near the 3 hour period. The reaction mixture is then cooled to 15°C and kept at this temperature for about 1 hour. The precipitate formed in the filtrate is filtered off rapidly and drained as much as possible to remove mother liquor and then washed with small amounts of cold alcohol. The solid product is immediately placed in a desiccator and dried over sulfuric acid for about 20 hours. 

Redox (reduction-oxidation) titrimetry is used primarily for nitrate detns. Five systems are in current use ferrous sulfate—dichromate, io dome trie, periodic acid oxidation (NaOH titrant), K permanganate, and titanous chloride-ferric ammonium sulfate. The ferrous sulfate— dichromate system is used for MNT DNT detns (Vol 2, C162-Lff Vol 6, F17-Rff Ref 17). In the iodometric procedure, the sample (ie, NG) is treated in a C02 atm with a satd soln of Mn chloride in coned HC1, the vol reaction products are bubbled thru a K iodide soln, and the liberated iodine is titrated with standard thiosulfate soln (Refs 1 17). The periodic... 

A. 2-Mercaptopyrimidine hydrochloride. Thiourea (61 g., 0.80 mole) and 600 ml. of ethyl alcohol (Note 1) are placed in a 2-1. three-necked flask equipped with a sealed mechanical stirrer, a reflux condenser, and a stopper. The stirrer is started, and 200 ml. of concentrated hydrochloric acid is added in one portion through the open neck. After several minutes, when the warm mixture has become homogeneous, 176 g. (0.80 mole) of commercial-grade 1,1,3,3-tetraethyoxypropane (Note 2) is added rapidly, the open neck is stoppered, and the yellow solution is boiled for about 1 hour with continuous stirring. During this period the reaction mixture darkens in color and the product separates (Note 3). 

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