Ethyl ether peroxide

This experiment was performed on XAD-4 quaternary resin in the OH- form, and desorption was by ethyl ether only (i.e., HC1 saturated ether not used). Calcium hypochlorite [Ca(OCl)2] was used to provide the required 2-ppm chlorine concentration. Millipore Super-Q water was salted according to the general procedure and passed over a 10-mL bed volume of resin (approximate dry weight = 6 g at 150 bed volumes/h. The resins were blown with nitrogen (3 lb/in2) for 10 s to remove residual water and eluted with 3 X 50-mL portions of ethyl ether. Peroxide formation was suppressed by the addition of 2% (v/v) ethanol. 

Ethyl ether, peroxide free Methanol containing 1% acetic acid Silica gel thin-layer plates (2.5 X 10 cm)... 

The decomposition products of ethyl ether (peroxides) are very reactive. Because of this reactivity, it should be remembered that the concentration of any percent level of mobile phase constituent is usually orders of magnitude larger than the concentration of the injected analyte. Therefore, even if only a small fioction of the solvent decomposes, the resulting concentration of decomposition product can rapidly reach and exceed the concentration of the analyte. When solvent/analyte reactions do occur, the observed chromatographic result ranges fit>m a shifted retention time and altered detector response factor, to tailed and/or split peaks, to total loss of anal e. 

Unpreserved THF poses the same set of stability problems as does unpreserved ethyl ether. Peroxides will form even with the presence of a preservative. ITie rate of formation is dependent upon storage conditions and the time between manufacture and use. One issue not noted above is that the ethers are typically packaged under nitroeen. The nitrogen is used to remove oxygen from the manufacturing and... 

Ethyl ether Eiquid air, chlorine, chromium(VI) oxide, lithium aluminum hydride, ozone, perchloric acid, peroxides... 

The nature of the initiation step, which may occur in a variety of ways, is not known in all cases. Commonly used ethers such as ethyl ether, isopropyl ether, tetrahydrofuran, and i)-dioxane are particulady prone to form explosive peroxides on prolonged storage and exposure to air and light (see Peroxides AND PEROXY COMPOUNDS, ORGANIC), and should contain antioxidants (qv) to prevent their build-up. One of the exceptions to the peroxide forming tendency of ethers is methyl fert-alkyl ethers such as methyl fert-butyl ether [1634-04-4] (MTBE) and fert-amyl methyl ether [994-05-8] (TAME). Both have shown htde tendency if any to form peroxides (2,8). 

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. 

Isopropyl Ether. Isopropyl ether is manufactured by the dehydration of isopropyl alcohol with sulfuric acid. It is obtained in large quantities as a by-product in the manufacture of isopropyl alcohol from propylene by the sulfuric acid process, very similar to the production of ethyl ether from ethylene. Isopropyl ether is of moderate importance as an industrial solvent, since its boiling point Hes between that of ethyl ether and acetone. Isopropyl ether very readily forms hazardous peroxides and hydroperoxides, much more so than other ethers. However, this tendency can be controlled with commercial antioxidant additives. Therefore, it is also being promoted as another possible ether to be used in gasoline (33). 

Peroxides. These are formed by aerial oxidation or by autoxidation of a wide range of organic compounds, including diethyl ether, allyl ethyl ether, allyl phenyl ether, dibenzyl ether, benzyl butyl ether, n-butyl ether, iso-butyl ether, r-butyl ether, dioxane, tetrahydrofuran, olefins, and aromatic and saturated aliphatic hydrocarbons. They accumulate during distillation and can detonate violently on evaporation or distillation when their concentration becomes high. If peroxides are likely to be present materials should be tested for peroxides before distillation (for tests see entry under "Ethers", in Chapter 2). Also, distillation should be discontinued when at least one quarter of the residue is left in the distilling flask. 

In opocinchenine the hydroxyl group must, therefore, be in the ortho-position relative to the point of attachment of the benzene ring to the quinoline nucleus. The relative positions of the two ethyl groups are determined by the fact that apocincheninic acid ethyl ether on oxidation with lead peroxide and sulphuric acid gives the lactone of hydroxyopo-cincheninic acid ethyl ether (I), which, on oxidation by sodium hypo-bromite, yields quinolylphenetoledicarboxylic acid (II). 

The assessors experienced an explosion while drying the oxide in ethyl ether. Rather drastic precautions are recommended in handling it [1], A preparation, allowed to stand for a week rather than the day specified, exploded during concentration [2], Amine oxides from the standard preparation are inclined to retain hydrogen peroxide of hydration unless it is destroyed during work-up. The perox-idate (or diperoxidate) of dimethylamine oxide would be expected to be far more dangerous than the oxide itself [3],... 

The triethylsilane reduction of the peroxy ethyl ether shown in Eq. 307 takes place at the C-0 bond of the methyl ether without reduction of either the iodide or the peroxide functionalities (Eq. 307).499In contrast, a bridged peroxy ether undergoes reduction of both C-0 bonds of the peroxide linkage rather than at the ether bridge (Eq. 308) 499... 

Korkisch and Koch [106,107] determined low concentrations of uranium in seawater by extraction and ion exchange in a solvent system containing trioctyl phosphine oxide. Uranium is extracted from the sample solution (adjusted to be 1 M in hydrochloric acid and to contain 0.5% of ascorbic acid) with 0.1 M trioctylphos-phine oxide in ethyl ether. The extract is treated with sufficient 2-methoxyethanol and 12 M hydrochloric acid to make the solvent composition 2-methoxyethanol-0.1 M ethereal trioctylphosphine acid-12 M hydrochloric acid (9 10 1) this solution is applied to a column of Dowex 1-X8 resin (Cl" form). Excess of trioctylphosphine oxide is removed by washing the column with the same solvent mixture. Molybdenum is removed by elution with 2-methoxyethanol-30% aqueous hydrogen peroxide-12 M hydrochloric... 

Methyl ethyl ether, 10 567 Methyl ethyl ketazine (MEK), 13 582, 583 Methyl ethyl ketone (MEK), 13 700 14 581 adipic acid solubility, l 555t azeotrope with methanol, 8 801 in MEK—MIPK—water system, 22 304-305, 306, 307 peroxide, 14 292... 

Note According to Sigma-Aldrich (2007), ethyl ether is stabilized with butylated hydroxytoluene (low ppm concentrations) or ethanol (1-2%) to prevent peroxide formation. 

Anhydrous Ethyl Ether. This is for those formulas calling for dry, pure, or anhydrous ether. The ether product from above is dried over thin slices of metallic sodium (metallic sodium wire works well also) for 24 hours. Then the ether is distilled on a water bath, over fresh (fresh means a different batch than what you used to dry with) metallic sodium. Note Ether develops explosive peroxides upon sitting for any length of time, even if just purchased from a supply house. Therefore, before handling ether, which has been stored, shake with ferrous sulphate or with lead peroxide. To keep peroxides from forming in fresh ether add several sections of copper or iron wire to the dark container and store in a cool place. 

Action of Aliphatic Amines on Slow Oxidation of Acetaldehyde and Ethyl Ether, and on Decomposition of Organic Peroxides in the Gas Phase... 

Aliphatic amines have much less effect on the later reactions of the gas-phase oxidation of acetaldehyde and ethyl ether than if added at the start of reaction. There is no evidence that they catalyze decomposition of peroxides, but they appear to retard decomposition of peracetic acid. Amines have no marked effect on the rate of decomposition of tert-butyl peroxide and ethyl tert-butyl peroxide. The nature of products formed from the peroxides is not altered by the amine, but product distribution is changed. Rate constants at 153°C. for the reaction between methyl radicals and amines are calculated for a number of primary, secondary, and tertiary amines and are compared with the effectiveness of the amine as an inhibitor of gas-phase oxidation reactions. 

Di ethyl ketene Peroxide (called Diathylketen Peroxyd in Ger), Q5H10O3 mw 130.14,-O 36.88% oil was prepd by treating an ethereal soln of diethylketene, (C2H5)2C C 0, with H202 at -20 an extremely expl compd decomp into CO2 diethylketoae if. allowed to stand in ether for several days (Refs 1 2)... 

Benzoyl peroxide [94-36-0J M 242.2, m 95 (dec). Dissolved in CHCI3 at room temperature and ppted by adding an equal volume of MeOH or pet ether. Similarly ppted from acetone by adding two volumes of distilled water. Has also been crystd from 50% MeOH, and from ethyl ether. Dried under vacuum at room temperature for 24h. Stored in a desiccator in the dark at 0°. When purifying in the absence of water it can be EXPLOSIVE and it should be done on a very small scale with adequate protection. Large amounts should be kept moist with water and stored in a refrigerator. [Kim et al. JOC 52 3691 1987]. 

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. 

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... 

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