Butanes aromatization

Product distribution in butane aromatization over alkaline earth cation exchanged Ga-Sil at 823K and 20 g-h-mof of W/ F. ... 

Catalytic properties of both Ga-silicate and Pt/Ga-silicate In n-C4Hio aromatization have been Investigated in a wide range of reaction conditions (at temperatures of 573-773 K, space velocities of 300-10000 h, total pressures of 0.1-0.5 MPa, partial pressures of butane and hydrogen of 5-100 kPa and 5-400 kPa, respectively. The introduction of platinum into the Ga-silicate was shown to result in dramatic effects on butane aromatization a decrease of the reaction temperature, an increase in the reaction rate and a drastic change in the product distribution. Platinum was found to accelerate both the initial paraffin and alicyclic intermediate dehydrogenation and suppressed the cracking process. 

To elucidate the Pt promoting effect in more detail we have investigated various catalytic features of n-butane aromatization with Ga- and Pt/Ga-silicates. XPS and TEM characterization of the catalysts studied was also performed. 

The n-butane aromatization was performed, using an automatic flow unit, in a quartz microreactor (the charge was 0.5g). The reaction conditions were varied in a wide range temperatures of 573-773 K, space velocities of 300-10000 h, total pressure of 0.1-0.5 MPa, butane partial pressure in He stream of 0.5-100 kPa. Some runs were made in hydrogen atmosphere, the hydrogen partial pressure was varied from 5 to 400 kPa. To avoid the flow gradient caused by butane condensation the feed was injected as a liquid at 1.5 MPa into a mixer heated to 673 K. The use of separate flow lines for catalyst activation and for the feedstock make it possible to measure the conversion and product distribution immediately after feedstock injection. The probes for analysis were taken automatically every 3-5 min. Normally, stable activity was reached after 5-10 min and remained practically constant over 4 hours. 

Oxidation of aldehydes. In the presence of butanal, aromatic aldehydes undergo oxidative coupling at room temperature to give benzils (8 examples, 62-75%). The same oxidation can be diverted to the carboxylic acid on addition of AC2O to the reaction medium. 

It was also shown by ESR that Ti3+ can substitute for Al3+ in ZSM-5 sample (26) leading specific acidic properties. In the case of Ga the appearance of an hydroxyl group at 3670cm l is a good criterion for a successful substitution of Ga3+ for Si + (17). This sample was observed to exhibit interesting catalytic properties for propane and butane aromatization in the famous Cyclar process particularly if you have both substituted Ga + (acidic feature) and Ga203 tiny particles (dehydrogenating feature). 

In industry, the elimination of asphaltenes from oil involves using propane or butane. The utilization of a lighter paraffin results in the heavier paraffins precipitating along with the asphaltenes thereby diminishing their aromatic character. The oil removed from its asphaltene fraction is known as deasphalted oil or DAO. The precipitated portion is called asphalt. 

Thermal Cracking. / -Butane is used in steam crackers as a part of the mainly ethane—propane feedstream. Roughly 0.333—0.4 kg ethylene is produced per kilogram / -butane. Primary bv-pioducts include propylene (50 57 kg/100 kg ethylene), butadiene (7-8.5 kg/100 kg), butylenes (5-20 kg/WO kg) and aromatics (6 kg/ToO kg). 

Petrochemicals are those chemicals produced from petroleum or natural gas and can be generally divided into three groups (/) aliphatics, such as butane and butene (2) cycloaliphatics, such as cyclohexane, cyclohexane derivatives, and aromatics (eg, ben2ene, toluene, xylene, and naphthalene) and (J) inorganics, such as sulfur, ammonia, ammonium sulfate, ammonium nitrate, and nitric acid. 

Thermoplastic copolyester elastomers are generally block copolymers produced from short-chain aUphatic diols, aromatic diacids, and polyalkjlene ether-diols. They are often called polyesterether or polyester elastomers. The most significant commercial product is the copolymer from butane-l,4-diol, dimethyl terephthalate, and polytetramethylene ether glycol [25190-06-1J, which produces a segmented block copolyesterether with the following stmcture. 

Manufacture of thiophene on the commercial scale involves reactions of the two component method type wherein a 4-carbon chain molecule reacts with a source of sulfur over a catalyst which also effects cyclization and aromatization. A range of suitable feedstocks has included butane, / -butanol, -butyraldehyde, crotonaldehyde, and furan the source of sulfur has included sulfur itself, hydrogen sulfide, and carbon disulfide (29—32). 

Evaporative emissions from vehicle fuel systems have been found to be a complex mixture of aliphatic, olefinic, and aromatic hydrocarbons [20,24,33]. However, the fuel vapor has been shown to consist primarily of five light paraffins with normal boiling points below 50 °C propane, isobutane, n-butane, isopentane, and n-pentane [33]. These five hydrocarbons represent the more volatile components of gasoline, and they constitute from 70 to 80 per cent mass of the total fuel vapor [24,33]. 

H2Sil2, CDCI3, —42°, 1-10 min, 100% yield. Aromatic ketals are cleaved faster than the corresponding aliphatic derivatives, and cyclic ketals are cleaved more slowly than the acyclic analogues, such as dimethyl ketals. Substituted ketals such as those derived from butane-2,3-diol, which react only slowly with Mc3SiI, can also be cleaved with H2Sil2. If the reaction is run at 22°, ketals and acetals are reduced to iodides in excellent yield. 

Butadiene is obtained mainly as a coproduct with other light olefins from steam cracking units for ethylene production. Other sources of butadiene are the catalytic dehydrogenation of butanes and butenes, and dehydration of 1,4-butanediol. Butadiene is a colorless gas with a mild aromatic odor. Its specific gravity is 0.6211 at 20°C and its boiling temperature is -4.4°C. The U.S. production of butadiene reached 4.1 billion pounds in 1997 and it was the 36th highest-volume chemical. ... 

Liquefied petroleum gas (LPG), a mixture of propane and butanes, is catalytically reacted to produce an aromatic-rich product. The first step is... 

Volatile solvents are fluids or gases contained in a wide variety of products (e.g., gasoline, paint thinner, butane gas) that have significant concentrations of aliphatic, aromatic, or halogenated hydrocarbons, which vaporize at room temperature. Because of their rapid absorption in the lungs, volatile solvents exert a rapid intoxicating effect. 

Pd2(dba)3/l,4-bis(diphenylphosphino)butane (DPPB) in the presence of 2-mercaptobenzoic acid <95TL1267>. The Af-allylindolines can be easily oxidized to the corresponding indoles at room temperature with o-chloranil. Additionally, Al-allylanilines were also found to undergo aromatic 3-aza-Cope rearrangements in the presence of Zeolite catalysts to give indoline derivatives as the major product <96TL5281>. 

The proline-catalyzed reaction has been extend to the reaction of propanal, butanal, and pentanal with a number of aromatic aldehydes and proceeds with high syn selectivity.197 The reaction can also be carried out under conditions in which the imine is formed in situ. Under these conditions, the conjugative stabilization of the aryl imines leads to the preference for the aryl imine to act as the electrophile. A good yield of the expected P-aminoalcohol was obtained with propanal serving as both the nucleophilic and the electrophilic component. The product was isolated as a 7-amino alcohol after reduction with NaBH4. 

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