Formaldehyde from paraffin

Research on the production of formaldehyde from methane, propane, and the hydrocarbon mixtures encountered in natural gas have been described by Bibb. Studies involving ethane, propane, and higher paraffins are also reported by Wiezevich and Frolich, who used iron, nickel, aluminum, and other metals as catalysts and employed pressures up to 135 atmospheres. 

Some of the chemicals mentioned above and others, such as chlorinated mbber or paraffin, antimony trioxide, calcium carbonate, calcium borate, pentaerythrithol, alumina trihydrate, titanium dioxide, and urea—melamine—formaldehyde resin, may be used to formulate fire retardant coatings. Many of these coatings are formulated in such a way that the films intumesce (expand) when exposed to fire, thus insulating the wood surface from further thermal exposure. Fire retardant coatings are mostly used for existing constmction. 

Goelz SE, Hamilton SR, Vogelstein B. Purification of DNA from formaldehyde-fixed and paraffin-embedded tissue. Biochem. Biophys. Res. Commun. 1985 130 118-126. 

In most cases, fixation may be carried out at room temperature. Duration of formalin fixation depends on the nature and the size of the specimen, and may vary from 15 min to 24 h. Longer fixation may be associated with a partial loss of the antigenicity of the component of interest. After formalin fixation, tissue samples are washed in three changes of the buffered saline (PBS) from 15 min to 2 h, but not longer than 24 hours on the whole, since the formaldehyde fixation is partially reversible. After washing in PBS, specimens may be either snap-frozen in liquid nitrogen for subsequent cryosectioning, or dehydrated and embedded in paraffin or synthetic resin. 

The direct conversion deals with the straight hydrogenation of carbon monoxide to paraffins, olefins and heteroatom (oxygen, nitrogen) containing products. The indirect conversion invokes intermediates such as methanol, methyl formate and formaldehyde. The latter ones in a consecutive reaction can yield a variety of desired chemicals. For instance, acetic acid can be synthesized directly from CO/H2, but for reasons of selectivity the carbonylation of methanol is by far the best commercial process. 

Gastric tumor tissue is fixed with 4% neutral formaldehyde for 1 day and embedded in paraffin (Kitayama et al., 2000). Paraffin sections (6 xm thick) are deparaffinized with xylene and rehydrated with ethanol. Centromeric a-satellite DNA probes and locus-specific identifier probes (c-myc and p53) are available from Vyis Inc. (Downers Grove, IL). The probes are labeled with orange (Cy 3) or green (PITC) using digoxigenin-ll-dUTP and nick translation. The sections are placed in 0.01 M citrate buffer (pH 6.0) and heated in a microwave oven for 10 min. This is followed by treatment with 0.2% pepsin in 0.01N HC1 for 10 min at 37°C, and then exposure to 0.1% NP40/2 X SSC for 10 min at the same temperature. 

Hydrogenation of carbon oxides with iron, cobalt, or nickel catalysts (Fischer-Tropsch process). Hydrocarbons are the main products Recovery and separation of oxygenated products obtained from CO and H2 Partial oxidation of nonaromatic hydrocarbon mixtures, e.g., petroleum, paraffins, and natural gas, to produce a mixture of products, such as esters, acids, aldehydes, ketones, and alcohols. This also includes higher fatty acids from petroleum and patents on formaldehyde production... 

Numerous materials have been reported and patented as catalysts for the oxidation of the gaseous paraffin hydrocarbons. The majority of these, consisting mainly of metals or metal oxides, are far too active and too nonspecific in action to permit the recovery of more than small amounts of intermediate oxidation product. With such relatively mild catalysts as copper oxide and glass surfaces, some high yields of formaldehyde have been obtained from methane and ethane under experimental conditions. Under conditions where less than 10 per cent of the entering hydrocarbon is oxidized, conversions of over 50 per cent of reacting hydrocarbon to formaldehyde have been reported. The use of elevated pressures, as shown in Fig. 9-6, for the oxidation of methane and ethane has been found to enhance yields of useful products. 

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