Butane Butyl ethers

There are other commercial processes available for the production of butylenes. However, these are site or manufacturer specific, eg, the Oxirane process for the production of propylene oxide the disproportionation of higher olefins and the oligomerisation of ethylene. Any of these processes can become an important source in the future. More recentiy, the Coastal Isobutane process began commercialisation to produce isobutylene from butanes for meeting the expected demand for methyl-/ rZ-butyl ether (40). 

Like propane, n-hutane is mainly obtained from natural gas liquids. It is also a hy-product from different refinery operations. Currently, the major use of n-hutane is to control the vapor pressure of product gasoline. Due to new regulations restricting the vapor pressure of gasolines, this use is expected to he substantially reduced. Surplus n-butane could be isomerized to isobutane, which is currently in high demand for producing isobutene. Isobutene is a precursor for methyl and ethyl tertiary butyl ethers, which are important octane number boosters. Another alternative outlet for surplus n-butane is its oxidation to maleic anhydride. Almost all new maleic anhydride processes are based on butane oxidation. 

BUTACRACKING A process for converting iso-butanes to iso-butene, which can then be converted to gasoline-blending components such as methyl /-butyl ether. Developed by Kinetics Technology International. 

Isobutylene is the most chemically reactive of the butylene isopiers. If the objective is just to get the isobutylene out of the C4 stream, it can be removed by reaction with methanol (CH3OH) to make MTBE (methyl tertiary butyl ether), by reaction with water to make TBA (tertiary butyl alcohol), by polymerization, or by solvent extraction. After that, butene-1 can be removed by selective adsorption or by distillation. That leaves the butene-2 components, together with iso- and normal butane, which are generally used as feed to an alkylation plant. 

Butane isomerization is usually carried out to have a source of isobutane which is often reacted with C3-C5 olefins to produce alkylate, a high octane blending gasoline [13]. An additional use for isobutane was to feed dehydrogenation units to make isobutene for methyl tert-butyl ether (MTBE) production, but since the phaseout of MTBE as an oxygenate additive for gasoline, this process has decHned in importance. Zeolitic catalysts have not yet been used industriaUy for this transformation though they have been heavily studied (Table 12.1). 

Isomerization. Isomerization is a catalytic process which converts normal paraffins to isoparaffins. The feed is usually light virgin naphtha and the catalyst platinum on an alumina or Zeolite base. Octanes may be increased by over 30 numbers when normal pentane and normal hexane are isomerized. Another beneficial reaction that occurs is that any benzene in the feed is converted to cyclohexane. Although isomerization produces high quality blendstocks, it is also used to produce feeds for alkylation and etherification processes. Normal butane, which is generally in excess in the refinery slate because of RVP concerns, can be isomerized and then converted to alkylate or to methyl tert-butyl ether (MTBE) with a small increase in octane and a large decrease in RVP. 

There are two major uses of /50-butane. One is dehydrogenation to isobutylene followed by conversion of the isobutylene to the gasoline additive methyl /-butyl ether (MTBE). However, current environmental issues may ban this gasoline additive. 

The reaction for making methyl-r-butyl ether proceeds quickly and highly selectively by reacting a mixed butene-butane fraction with methyl alcohol in the liquid phase on a fixed bed of an acidic ion-exchange resin catalyst (Fig. 1). 

Direct dehydroisomerisation (DHI) of n-butane into isobutene over bifunctional zeolite-based catalysts represents a potential new route for the generation of isobutene utilising cheap n-butane feedstock. Isobutene is used worldwide for production of methyl tert-butyl ether (MTBE) and polyisobutylene. It is currently obtained via extraction from refinery/cracker C4 streams or via conversions of isobutane (in one step) or n-butane (in two steps).1,2 Isobutene can also be produced via the isomerisation of n-butenes,3 although there is no evidence that this is practised commercially.2,3... 

SYNS l-BUTOXYBUTANE BUTYL ETHER pOT) DI-n-BUTYL ETHER pOTl DIBUTYL OXIDE ETHERBUTYLIQUE (FRENCH) l,l -OXYBIS(BUTANE)... 

SYNS BIS(2-BUTYL)ETHER BUTANE, 2,2 -OXYBIS-(9CI) DI-sec-BUTYL ETHER 2,2 -OXYBISBUTANE... 

SYNS BUTANE, l-METHOXY-(9CI) ETHER, BUTYL METHYL olMETHOXYBUTANE 1-METHOXYBUTANE METHYL BUTYL ETHER METHYL n-BLnTYL ETHER... 

SYNS BUTOXYETHENE BUTYL VINYL ETHER BUTYL VINYL ETHER (inhibited) l-(ETHENYLOXY) BUTANE VINYT-n-BUTYL ETHER... 

CyclopropanecarboxaUehytte. Dehydration of a mixture of cis- and froni-cyclo-butane-l,2-diol (I) with boron trifluoride n-butyl etherate at 230° yields cyclopropane-carboxaldehyde (2) in 65-80% yield. Dehydration of (I) with p-toluenesulfonic acid gives (2) in somewhat lower yields (66%)- ... 

The hydrogenation of carbon dioxide was studied using composite catalysts comprised of Fe-Zn-M (M= Cr, Al, Ga, Zr) catalysts and the HY zeolite, where the methanol synthesis and the methanol-to-gasoline(MTG) reaction are combined. The results show that light olefins are important intermediates for iso-butane formation. In all of the cases, the selectivity of isobutane, which can be used as a reactant in subsequent methyl-tert-butyl ether (MTBE) synthesis, was the highest in hydrocarbons. 

Iso-butane is a highly demanded chemical in the refinery industry for the production of alkylates (by alkylation with butenes), and methyl tert-butyl ether (MTBE) (from isobutene and methanol), both important additives for reformulated gasolines. n-Butane isomerization is performed over platinum supported on chlorinated alumina. The chlorine compound which is continuously supplied to the feed in order to maintain the activity [1] is harmful to the environment. 

Although the formula can vary by manufacturer, reformulated gasoline usually has polluting components like butane, olefins, and aromatics removed and an octane-enhancer like methyl tertiary butyl ether (MTBE) added. MTBE can reduce carbon monoxide by 9%, hydrocarbons by 4%, and nitrogen oxides by 5%, and improves combustion efficiency. It was widely used in California, Arizona, and Nevada, but is being phased out after it was found to contaminate water supplies. 

A representative profile for a column in which methanol and f-butene are reacted to form methyl tert-butyl ether (MTBE) is shown in Figure 12.22. Note that an inert n-butane, is not shown. The reactants are fed at different stages, and the desired product, MTBE, is removed from the bottom of the column in high purity. 

The cheapest source of n-l-butene is raffinate II , a C4 cut from which butadiene (by extraction) and isobutene (by conversion into methyl t-butyl ether) have been removed. The remaining mixture of C4 hydrocarbons contains about 50-65% of n-1-butene, the remainder consisting of cis/trans n-2-butene and saturated butanes. A high concentration of n-1-butene in the raffinate is desirable for obvious reasons. On the other hand, the price for raffinate II is directly proportional to its content of n-1-butene. Therefore it is an unconditional requirement for the process to be compatible with different concentrations of n-l-butene in the feedstock. 

Beilstein Handbook Reference) Bis(2-butyl)ether BRN 1733014 Butane, 2,2 -oxybis- sec-Butyl ether Di-sec-butyl ether EINECS 229-961-6, Liquid bp = 121° d S = 0,756. 

Beilstein Handbook Reference) AI3-00402 BRN 1732752 Butane, 1,1 -oxybis- Butyl ether Butyl oxide CCRIS 6010 Dibutyl ether Di-n-butyl ether EINECS 205-575-3 Ether butylique HSDB 306 NSC 8459. Uquid mp = -95.2 bp = 140.2° d = 0.7684 insoluble in H2O, slightly soluble in CCI4, very soluble in MeaCO, freely soluble in EtOH, EtaO. 

The determination of fluorine in various liquid and gaseous hydrocarbons is vital at many points in the refining process primarily in any blend component that has been sourced fiom the hydrogen fluoride (HF) Alkylation Unit. Fluorinated compounds poison process catalysts therefore, it is essential that process feeds be as free of fluorine as possible. As an example, butane is used to produce methyl tertiary-butyl ether (MTBE). The butane must be fluorine free prior to butane isomerization to prevent the poisoning of the process catalyst, fri addition, any HF acid or its combustion products may be extremely destructive in any environment. Therefore, any finished hydrocarbon product or synthesized material that is utilized in the presence of sufficient heat (i.e., car engine), such as frel and lubricating oils, must be free of fluoride. 

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