Ethyl peroxide, detection

Absolute diethyl ether. The chief impurities in commercial ether (sp. gr. 0- 720) are water, ethyl alcohol, and, in samples which have been exposed to the air and light for some time, ethyl peroxide. The presence of peroxides may be detected either by the liberation of iodine (brown colouration or blue colouration with starch solution) when a small sample is shaken with an equal volume of 2 per cent, potassium iodide solution and a few drops of dilute hydrochloric acid, or by carrying out the perchromio acid test of inorganic analysis with potassium dichromate solution acidified with dilute sulphuric acid. The peroxides may be removed by shaking with a concentrated solution of a ferrous salt, say, 6-10 g. of ferrous salt (s 10-20 ml. of the prepared concentrated solution) to 1 litre of ether. The concentrated solution of ferrous salt is prepared either from 60 g. of crystallised ferrous sulphate, 6 ml. of concentrated sulphuric acid and 110 ml. of water or from 100 g. of crystallised ferrous chloride, 42 ml. of concentrated hydiochloric acid and 85 ml. of water. Peroxides may also be removed by shaking with an aqueous solution of sodium sulphite (for the removal with stannous chloride, see Section VI,12). 

Ethyl ether [60-29-7] M 74.1, b 34.6 /760mm, d 0.714, n s 1.3555, n 1.35272. Usual impurities are water, EtOH, diethyl peroxide (which is explosive when concentrated), and aldehydes. Peroxides [detected by liberation of iodine from weakly acid (HCl) solutions of KI, or by the blue colour in the ether layer when Img of Na2Cr2O7 and 1 drop of dil H2SO4 in 1ml of water is shaken with 10ml of ether] can be removed in several different ways. The simplest method is to pass dry ether through a column of activated alumina (80g AbOa/VOOml of ether). More commonly, IL of ether is shaken repeatedly with 5-lOml of a soln comprising... 

Hydrocarbons, for use in explosives, 24 Hydrogen peroxide in ethyl ether, detection of, aS... 

Hydrogen peroxide has also been analy2ed by its chemiluminescent reaction with bis(2,4,6-trichlorophenyl) oxalate and perylene in a buffered (pH 4—10) aqueous ethyl acetate—methanol solution (284). Using a flow system, intensity was linear from the detection limit of 7 x 10 M to at least 10 M. 

Analytical Methods. Most of the analytical and testing methods used for ethyl ether are conventional laboratory methods. Ethyl ether that is to be used for anesthetic purposes or in processes that involve heating or distiHation must be peroxide-free, and should pass the USP standard test with potassium iodide. This test detects approximately 0.001% peroxide as hydrogen peroxide. 

Tamaoku and colleagues presented an efficient enzymatic photometric determination of hydrogen peroxide ffiat is essentially a color reaction resulting from the oxidative condensation of A/-ethyl-A/-(2-hydroxy-3-sulfopropyl)aniline derivatives wiffi 4-aminoantipyrine in the presence of hydrogen peroxide and peroxidase (82CPB2492). A similar calorimetric detection of hydrogen peroxide has been patented (83GEP3301470). 

Dan et al. found that Brij-35 also produces an enhancement of the CL intensity of the reaction of fti.v AL[2-(A, -rnclhyl-2 -pyridiniumyl)ethyl]-AL [(trifluoromethyl)sulfonyl]]oxamide with hydrogen peroxide in the presence of some fluorophors [40], To be precise, the CL intensity increased by a factor of 130 for 8-aniline-1-naphthalenesulfonic acid (ANS) and 5.6 forrhodamine B (RH B), compared to the CL intensity in the absence of surfactant. This leads to an increase of 2-3 orders of magnitude in the linear dynamic ranges and a more precise determination of these analytes. However, improvement of the detection... 

Burton et al. reported the assay of benzoic acid, ethyl benzoate, and benzoyl peroxide in dermatological gels and lotions [33]. These workers used a Waters p-Bondapak C g column and UV detection at 254-nm. A mixture of 50% aqueous acetonitrile was used as the mobile phase. 

The ozonide (4.3 grams) in ethyl acetate (25 ml.) was shaken with reduced platinum oxide (approximately 50 mg.) in a Burgess-Parr apparatus containing oxygen at 50 p.s.i.g. for 24 hours. The solution was aldehyde-free and gave a negative peroxide test. There was no detectable... 

These must be glycerol free. A solvent extraction procedure must be used prior to GC-MS [2, 5, 6]. If the sample is prepared with ion-exchange chromatography, the glycerol will remain in the neutral fraction and not be detected by GC-MS [2, 5]. Hydrochloric acid (5 N), pH paper, sodium sulfate (anhydrous), ethyl acetate (free of contaminants), diethyl ether (anhydrous, peroxide-free, and free of contaminants except 2,6-ditertbutylcresol, which is an antioxidant found in all ether), and malonic acid (26.25 mg/50 ml methanol). 

Benzyl alcohol [100-51-6] M 107.2, f.p. -15.3°, b 205.5 , 93°/10mm, d 0.981, n 1.54033. Usually purified by careful fractional distn at reduced pressure in the absence of air. Benzaldehyde, if present, can be detected by UV absorption at 283nm. Also purified by shaking with aq KOH and extracting with peroxide-free ethyl ether. After washing with water, the extract was treated with satd NaHS sol, filtered, washed and dried with CaO and distd under reduced pressure [Mathews JACS 48 562 7926]. Peroxy compounds can be removed by shaking with a soln of Fe(II) followed by washing the alcohol layer with distd water and fractionally distd. 

The authors devoted their investigations to the development of a peroxidase-biomimetic sensor for determining trace quantities of ethyl alcohol in various solutions. In all tests the reaction system represented a mixture of microamounts of hydrogen peroxide and ethyl alcohol in an aqueous medium. The task was to determine the effect of the H202 C2H50H ratio on the detection ability of the biomimetic electrode. 

This ketone is unique amongst those studied in that it apparently exhibits no region of negative temperature coefficient of the rate and no cool flames have been observed [45]. The pressure—time curves were similar to those of methyl iso-propyl ketone at 310 °C, the reaction accelerating smoothly and then stopping suddenly [46]. Analyses of the combustion products have been made at various stages of the reaction at 270, 310 and 350 °C. Carbon monoxide, carbon dioxide, hydrogen peroxide, iso-butene-1 2-oxide, methanol, methyl ethyl ketone and acetaldehyde were all detected, and towards the end of the reaction iso-butene and methane were also formed. 

Fig. 1. An immuno-slot blot fin the detection of 0 -hydro]Q thy]deoxygiianosine. Calf thymus DNA was hydrm ethylated in vitro with 6.6 mAf of hydroxyethyl-nitrosourea. Aliquots containing 300, 100, 33.3, 11.1, 3.7, 1.2, and 0 finol of O -hydroxyethyldeoxyguanosine in 3 (ig ofheat-denatured DNA (corresponding to 217-0 pmol/tnol of deoxyguanosine) were blotted onto nitrocellulose and incubated with a rabbit anti-O -hydroxyethyldeoiQ guanosine serum (NPZ-146-2,1 15,000 see ref. 4). Bound antibodies were reacted with a goat-antirabbit IgG horseradish peroxidase conjugate and detected with hydrogen peroxide and 4-chloro-l-naphth6l.

Solid benzenediazonium chloride 251 Aniline hydrochloride (5 g) is suspended in a mixture of glacial acetic acid (30 ml) and dry, peroxide-free dioxan (30 ml). The suspension is cooled in an ice-salt bath, and ethyl nitrite is led in until all the solid has dissolved (an excess is detected by coloration of starch-iodide paper). Dry dioxan (150 ml) is then added in one portion, whereupon the benzenediazonium chloride separates as fine, white crystals. They are filtered off and washed twice with dioxan (25-ml portions). 

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