OAKIN Oxidation


V ariable Air oxidation Oxygen oxidation  [c.457]

The metallic catalysts for exliaust pollution control are designed to perform three functions. The air/fuel ratio employed in combustion engines creates exhaust products which are a mixture of hydrocarbons, carbon oxides, and niU ogen oxides. These must be rendered environmentally innocuous by reactions on the catalyst such as  [c.138]

The degradation of a plastic occurs due to a breakdown of its chemical structure. It should be recognised that this breakdown is not necessarily caused by concentrated acids or solvents. It can occur due to apparently innocuous mediums such as water (hydrolysis), or oxygen (oxidation). Degradation of plastics is also caused by heat, stress and radiation. During moulding the material is subjected to the first two of these and so it is necessary to incorporate stabilisers and antioxidants into the plastic to maintain the properties of the material. These additives also help to delay subsequent degradation for an acceptably long time.  [c.26]

Silica gel and aluminium oxide layers are highly active stationary phases with large surface areas which can, for example, — on heating — directly dehydrate, degrade and, in the presence of oxygen, oxidize substances in the layer This effect is brought about by acidic silanol groups [93] or is based on the adsorption forces (proton acceptor or donor effects, dipole interactions etc) The traces of iron in the adsorbent can also catalyze some reactions In the case of testosterone and other d -3-ketosteroids stable and quantifiable fluorescent products are formed on layers of basic aluminium oxide [176,195]  [c.88]

Oxygen (oxide ions) in crystal lattices can be progressively removed by systematically  [c.643]

The main route to produce acrolein is through the catalyzed air or oxygen oxidation of propylene.  [c.215]

There is a reaction between beryllium and nitrogen that starts at about 750°C and is appreciable at 850°C, beryllium nitride being formed". The reaction with oxygen is less sluggish and at 900°C in oxygen oxidation proceeds at about twice the rate of nitride formation. Thus when beryllium is heated in air, beryllium nitride forms only a small proportion of the total scale —about 0-75% after 1 h at 1 000°C.  [c.836]

Many processes are based on an oxidation step for which air would be the first obvious source of oxygen. A partial list would include acetic acid, acetylene, acrylic acid, acrylonitrile, carbon black, ethylene oxide, formaldehyde, maleic anhydride, nitric acid, phenol, phthalic anhydride, sulfuric acid, titanium dioxide, vinyl acetate, and vinyl chloride. Clearly, because the nitrogen in the air is not required by the reaction, it must be separated at some point. Because gaseous separations are difiicult, the nitrogen is normally separated using a purge, or alternatively, the reactor is forced to as high a conversion as possible to avoid recycling. If a purge is used, the nitrogen will carry with it process materials, both feeds and products, and will probably require treatment before final discharge. If the air for the oxidation is substituted by pure oxygen, then, at worst, the purge will be very much smaller. At best, it can be eliminated altogether. Of course, this requires an air separation plant upstream of the process to provide the pure oxygen. However, despite this disadvantage, very significant benefits can be obtained, as the following example shows.  [c.283]

Incineration of toxic materials such as halogenated hydrocarbons, pesticides, herbicides, etc. requires a sustained temperature of 1100 to 1300°C in an excess of oxygen. The incinerator stack gases will contain acid gases such as hydrogen chloride, oxides of sulfur, and oxides of nitrogen depending on the waste being incinerated. These acid gases require scrubbers to treat the gaseous waste stream. This scrubbing, in turn, produces an aqueous effluent.  [c.299]

This equation indicates that every molecule of urea requires 9/2 molecules of oxygen for complete oxidation. The oxygen required for the reactions depletes the receiving water of oxygen, causing the death of aquatic life.  [c.308]

While the BOD test gives a good indication of the effect the effluent will have on the environment, it requires 5 days to carry out. The chemical oxygen demand (COD) test has been developed to give a more rapid result. In the COD test, acidic oxidation with potassium dichromate is used. COD results are generally higher than BOD results because the COD test oxidizes materials that are only slowly biodegradable. Although the COD test provides a very strong oxidizing environment, certain compounds are not oxidized.  [c.308]

Another test is the total oxygen demand (TOD) test, which oxidizes the waste in the presence of a catalyst at 900°C in a stream of air. Under these harsh conditions, all the carbon is oxidized to CO2. The oxygen demand is calculated from the difference in oxygen content of the air before and after oxidation. The resulting value of TOD  [c.308]

Solution First, calculate the theoretical oxygen demand from the equation that represents the overall oxidation of the acetone  [c.309]

There are many ionic Co(II) compounds, e.g. halides and a great range of largely octahedral Co(IIl) complexes. Other oxidation states for Co are ], e.g. [Co(CO)4]" 0, Co2(CO)s -Hl,CoBr(PR3)3 and [Co(NCR)j]% -f-4,(CoFe) ". Cobalt complexes are oxygen-carriers. It can be present in enzymes and may be of great importance in their action.  [c.104]

Bina Selenides. Most biaary selenides are formed by beating selenium ia the presence of the element, reduction of selenites or selenates with carbon or hydrogen, and double decomposition of heavy-metal salts ia aqueous solution or suspension with a soluble selenide salt, eg, Na2Se or (NH 2S [66455-76-3]. Atmospheric oxygen oxidizes the selenides more rapidly than the corresponding sulfides and more slowly than the teUurides. Selenides of the alkah, alkaline-earth metals, and lanthanum elements are water soluble and readily hydrolyzed. Heavy-metal selenides are iasoluble ia water. Polyselenides form when selenium reacts with alkah metals dissolved ia hquid ammonia. Metal (M) hydrogen selenides of the M HSe type are known. Some heavy-metal selenides show important and useful electric, photoelectric, photo-optical, and semiconductor properties. Ferroselenium and nickel selenide are made by sintering a mixture of selenium and metal powder.  [c.332]

There is no evidence for the existence of thallic hydroxide addition of hydroxide to an aqueous solution of a T1(III) salt gives TI2O2 instead. ThaHous hydroxide can be isolated as yellow needles by the hydrolysis of thaHous ethoxide [20398-06-5] which is conveniendy prepared as a heavy oH by the oxygen oxidation of thallium metal in ethanol vapor. ThaHous hydroxide darkens at room temperature and decomposes to TI2O and H2O on warming.  [c.469]

The compound undergoes the usual chemical reactions of alcohols or aromatic compounds. The hydroxyl group can be replaced by halogens and can be readily esterified with practically any organic acid in the presence of sulfuric acid as a catalyst. It combines with anhydrous calcium chloride to give a sohd addition compound formerly used in purifying the alcohol. It forms acetals with many aldehydes. Phenethyl alcohol dehydrates in the presence of acids to bis(phenethyl)ether [93-96-9], whereas with alkaU, it gives styrene. With other alcohols, it forms mixed ethers. Dehydrogenation to phenylacetaldehyde can be effected with finely divided metallic catalysts, such as copper and silver or zinc oxide in the presence of oxygen. Oxidation with dichromate or permanganate yields phenylacetic acid [103-82-2], and finally benzoic acid. With nitric oxide the primary product of oxidation is phenylacetic acid with similar amounts of phenylacetaldehyde (60). Since it contains an aromatic ring, PEA can be nitrated, sulfonated, and chlorinated it can be hydrogenated to 2-cyclohexylethanol [4442-79-9] (61—64), which is not only a natural product (65,66), but also a perfume chemical. It has also been found in fresh tearose leaves (67).  [c.61]

Photooxidafions are also iudustriaHy significant. A widely used treatment for removal of thiols from petroleum distillates is air iu the presence of sulfonated phthalocyanines (cobalt or vanadium complexes). Studies of this photoreaction (53) with the analogous ziuc phthalocyanine show a facile photooxidation of thiols, and the rate is enhanced further by cationic surfactants. For the perfume iudustry, rose oxide is produced iu low toimage quantifies by singlet oxygen oxidation of citroneUol (54). Rose bengal is the photosensitizer.  [c.435]

Unbumed hydrocarbons in the exhaust originate primarily from crevices in the combustion chamber, such as gaps between the piston and cylinder wall, where the combustion flame caimot bum. The composition of unbumed hydrocarbons is dictated primarily by the composition of the fuel (12). Carbon monoxide results from areas of insufficient oxygen. Oxides of nitrogen are produced in the high temperature 2ones during combustion by the reaction of nitrogen molecules and oxygen atoms thermally produced from oxygen and oxygen-containing species, according to the Zeldovich mechanism  [c.483]

Peracrd oxidation of thiophene yields the non-aromatic sulfoxide or sulfone. These react further by way of Diels-Alder addition to give (102). Trapping experiments in the presence of p-benzoquinone have also demonstrated the formation of 2-hydroxythiophene S-oxide (103) (76ACS(B)353). Stable sulfones have been obtained from oxidation of 2,5-dimethyl-thiophene and benzo[6]thiophene. Singlet oxygen oxidation of 2,5-dimethylthiophene results in the formation of a cyclic peroxide which subsequently ring opens. Very vigorous oxidation of the thiophene ring results in breakdown to maleic and oxalic acids and ring sulfur is oxidized to sulfuric acid.  [c.58]

Another reflection of the coupling between these reactions lies in their values of AGunder cellular conditions (Table 19.1). In spite of its strongly negative AG°, the phosphoglycerate kinase reaction operates at equilibrium in the erythrocyte (AG = 0.1 kj/mol). In essence, the free energy available in the phosphoglycerate kinase reaction is used to bring the three previous reactions closer to equilibrium. Viewed in this context, it is clear that ADP has been phos-phorylated to form ATP at the expense of a substrate, namely, glyceraldehyde-3-phosphate. This is an example of substrate-level phosphorylation, a concept that will be encountered again. (The other kind of phosphorylation, oxidative phosphorylation, is driven energetically by the transport of electrons from appropriate coenzymes and substrates to oxygen. Oxidative phosphorylation will be covered in detail in Chapter 21). Even though the coupled reactions exhibit a very favorable AG°, there are conditions (i.e., high ATP and 3-phosphoglyc-erate levels) under which Equation 19.9 can be reversed, so that 3-phospho-glycerate is phosphorylated from ATP.  [c.626]

Arsenic lII) oxide, AS2O3 (white arsenic). Formed by burning As in air, contains AS4O6 molecules or AsOa units joined by oxygen bridges. AS2O3 is used in glass manufacture and as arsenates(III) in insecticides, weedkillers and defoliants. It is used as a standard reducing agent (with I2 solution). It gives arsenates(III) with alkalis.  [c.42]

Chromium trioxide. CrOj. Red precipitate from [Cr04p plus cone. H2SO4, m.p. 198 C, loses oxygen at 420" C. CrOa is a powerful oxidizing agent and is used as such. Acidic, gives [Cr04] - with water.  [c.99]


See pages that mention the term OAKIN Oxidation : [c.27]    [c.290]    [c.291]    [c.700]    [c.233]    [c.543]    [c.192]    [c.162]    [c.138]    [c.587]    [c.183]    [c.329]    [c.449]    [c.309]    [c.311]    [c.10]    [c.18]    [c.30]    [c.38]    [c.47]    [c.51]    [c.52]    [c.75]    [c.76]    [c.93]    [c.96]    [c.111]    [c.112]   
Organic syntheses based on name reactions and unnamed reactions (1994) -- [ c.84 ]