Naphtha presence

Butane-Naphtha Catalytic Liquid-Phase Oxidation. Direct Hquid-phase oxidation ofbutane and/or naphtha [8030-30-6] was once the most favored worldwide route to acetic acid because of the low cost of these hydrocarbons. Butane [106-97-8] in the presence of metallic ions, eg, cobalt, chromium, or manganese, undergoes simple air oxidation in acetic acid solvent (48). The peroxidic intermediates are decomposed by high temperature, by mechanical agitation, and by action of the metallic catalysts, to form acetic acid and a comparatively small suite of other compounds (49). Ethyl acetate and butanone are produced, and the process can be altered to provide larger quantities of these valuable materials. Ethanol is thought to be an important intermediate (50) acetone forms through a minor pathway from isobutane present in the hydrocarbon feed. Formic acid, propionic acid, and minor quantities of butyric acid are also formed. 

Olefins are produced primarily by thermal cracking of a hydrocarbon feedstock which takes place at low residence time in the presence of steam in the tubes of a furnace. In the United States, natural gas Hquids derived from natural gas processing, primarily ethane [74-84-0] and propane [74-98-6] have been the dominant feedstock for olefins plants, accounting for about 50 to 70% of ethylene production. Most of the remainder has been based on cracking naphtha or gas oil hydrocarbon streams which are derived from cmde oil. Naphtha is a hydrocarbon fraction boiling between 40 and 170°C, whereas the gas oil fraction bods between about 310 and 490°C. These feedstocks, which have been used primarily by producers with refinery affiliations, account for most of the remainder of olefins production. In addition a substantial amount of propylene and a small amount of ethylene ate recovered from waste gases produced in petroleum refineries. 

The principal route for production of isoprene monomer outside of the CIS is recovery from ethylene by-product C streams. This route is most viable where ethylene is produced from naphtha or gas oil and where several ethylene plants are located in relatively close proximity to the isoprene plant. Although the yield of isoprene per mass of ethylene is quite low, there is enough ethylene produced to provide a large portion of demand. Because of the presence of / -pentane in these streams which a2eotropes with isoprene, extractive distillation must be used to recover pure isoprene. Acetonitrile is the most common solvent, but dimethylformamide is also used commercially. 

Steam Reforming Processes. In the steam reforming process, light hydrocarbon feedstocks (qv), such as natural gas, Hquefied petroleum gas, and naphtha, or in some cases heavier distillate oils are purified of sulfur compounds (see Sulfurremoval and recovery). These then react with steam in the presence of a nickel-containing catalyst to produce a mixture of hydrogen, methane, and carbon oxides. Essentially total decomposition of compounds containing more than one carbon atom per molecule is obtained (see Ammonia Hydrogen Petroleum). 

Acetic acid (qv) can be produced synthetically (methanol carbonylation, acetaldehyde oxidation, butane/naphtha oxidation) or from natural sources (5). Oxygen is added to propylene to make acrolein, which is further oxidized to acryHc acid (see Acrylic acid and derivatives). An alternative method adds carbon monoxide and/or water to acetylene (6). Benzoic acid (qv) is made by oxidizing toluene in the presence of a cobalt catalyst (7). 

A broad range of solvents can be used in solvent-borne BR and PIB adhesives. Hydrocarbon (hexane, heptane, naphtha) and chlorinated solvents (perchloroethy-lene) can be used they provide higher viscosities. The presence of small amounts of stabilizer may cause cloudy solutions and settling is rarely produced. There is a logarithmic relationship between viscosity and solids content. In fact, a small... 

By 1950 a reforming process was introduced using a catalyst to improve the yield loline components while minimizing the formation of unwanted material. In catalytic as in thermal reforming, a naphtha-type material serves as the feedstock, but the reactions are carried out in the presence of... 

Naphthas obtained from cracking units generally contain variable amounts of olefins, higher ratios of aromatics, and branched paraffins. Due to presence of unsaturated compounds, they are less stable than straight-mn naphthas. On the other hand, the absence of olefins increases the stability of naphthas produced by hydrocracking units. In refining operations, however, it is customary to blend one type of naphtha with another to obtain a required product or feedstock. 

Kerosine, a distillate fraction heavier than naphtha, is normally a product from distilling crude oils under atmospheric pressures. It may also he obtained as a product from thermal and catalytic cracking or hydrocracking units. Kerosines from cracking units are usually less stable than those produced from atmospheric distillation and hydrocracking units due to presence of variable amounts of olefinic constituents. 

Light naphtha containing hydrocarbons in the C5-C7 range is the preferred feedstock in Europe for producing acetic acid by oxidation. Similar to the catalytic oxidation of n-butane, the oxidation of light naphtha is performed at approximately the same temperature and pressure ranges (170-200°C and =50 atmospheres) in the presence of manganese acetate catalyst. The yield of acetic acid is approximately 40 wt%. 

Manufacture Made by thermal (high-temperature) cracking in the presence of steam of any available low-cost hydrocarbon such as ethane and propane, naphthas (C5-C10), and so-called gas oils (C10-C30). Many other organic compounds are produced during the cracking step, depending on the starting material fed to the reactor (cracker). CH3 CH3 CH2=CH2-PH2... 

A considerable amount of the strain in l,8-bis(dimethylamino)naphtha-lene is relieved by protonation and the N—H N bond length (260 pm) in the protonated amine shows that the molecule is able to adopt a conformation [55] with an intramolecular hydrogen bond (Truter and Vickery, 1972). The infra-red spectrum of protonated l,8-bis(dimethylamino)naphthalene and the chemical shift (5 19.5) of the acidic proton in the nmr spectrum confirm the presence of an intramolecular hydrogen bond (Alder et al., 1968). The magnitude of the isotope effect on the chemical shift (Altman et al., 1978) and the appearance of two Nls peaks in the photoelectron spectrum... 

Alkenes (also called olefins). These constituents are characterized by the presence of branched or unbranched chains of carbon atoms. Alkenes are not generally found in crude oil but are common in refined products, such as naphtha (a precursor to gasoline). Common gaseous alkenes include ethylene (CH2=CH2) and propene (also called propylene, CH3CH=CH2). 

Liquid fuels such as distillate, naphtha, diesel oils, and heavy fuel oil can be reformed in partial oxidation reformers. All commercial POX reactors employ noncatalytic POX of the feed stream by oxygen in the presence of steam with reaction temperatures of approximately 1,300 to 1,500°C (2,370 to 2,730°F) (18). For illustration, the overall POX reaction for pentane is... 

Jang and McDow (1997) studied the photodegradation of benzo[a]anthracene in the presence of three common constituents of atmospheric aerosols reported to accelerate benzo [a] anthracene, namely 9,10-anthroquinone, 9-xanthone, and vanillin. The photo-degradation experiments were conducted using a photochemical reactor equipped with a 450-W medium pressure mercury arc lamp and a water bath to maintain the solution temperature at 16 °C. The concentration of benzo [a] anthracene and co-solutes was 10" M. Irradiation experiments were conducted in toluene, benzene, and benzene-c/e- Products identified by GC/MS, FTIR, and NMR included benzo[a]an-thracene-7,12-dione, phthalic acid, phthalic anhydride, 1,2-benzenedicarboxaldehyde, naphtha-lene-2,3-dicarboxylic acid/anhydride, 7,12-dihydrobenzo[a]anthracene, 10-benzyl-10-hydroan-thracen-9-one, benzyl alcohol, and 1,2-diphenylethanol. 

The oldest cresol production method used in the United States is through the recovery of fractional distillates from coal tars. Most domestic cresols are formed via catalytic and thermal cracking of naphtha fractions during petroleum distillation. Since 1965, quantities of coal tar and petroleum isolates have been insufficient to meet the rising demand. Consequently, several processes for the manufacture of the various isomers have been developed. One General Electric facility produces o-cresol at an annual capacity of 10,000 tons by the methylation of phenol in the presence of catalysts. The Sherman-Williams Company uses the toluene sulfonation process and maintains an annual capacity for p-cresol of 15,000 tons. The Hercules Powder Company produced p-cresol until 1972 by the cymene- cresol process. 

Low fuel viscosity can be due to the presence of low-boiling-point, low-molecular-weight compounds in the fuel. Contamination with low-boiling-point compounds such as solvents, gasoline, and petroleum naphtha can dramatically reduce the viscosity of distillate fuel and residual fuel oil. 

The 1 1 1 complex [54] is obtained by reaction of the cryptand 15 with 2,3-naphtha-lenediol in the presence of water. The water molecule is bound by bifurcated hydrogen bonds to four oxygen atoms of the cryptand, one binds symmetrically (HO = 2.33 and 2,56 A) while the other bind assymmetrically (2.03 and 2.56 A). The 2,3-naph-thalenediol forms one intramolecular hydrogen bond while the second diol is coordinated to the water molecule (H- O = 1.79 A). 

There was some indication that the presence of nontoxic oil in the emulsion caused a tendency toward selectivity. For example, a 10% emulsion of either methylnaphthalene or dimethylnaphthalene killed the greenhouse test plants with no selectivity. The addition of 20% nontoxic oil, however, greatly reduced the carrot injury without an apparent reduction in toxicity to the other species. Tests were conducted with water emulsions of highly phytotoxic naphthas which contained 75 to 85% aromatics and had boiling ranges of to 550 F. Excellent selectivity was obtained in some tests, but in other tests the emulsion gave severe injury to carrots. The results with emulsions of high aromatic naphthas were inconclusive. 

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