Methyl/-butyl ether demand

High temperature steam reforming of natural gas accounts for 97% of the hydrogen used for ammonia synthesis in the United States. Hydrogen requirement for ammonia synthesis is about 336 m /t of ammonia produced for a typical 1000 t/d ammonia plant. The near-term demand for ammonia remains stagnant. Methanol production requires 560 m of hydrogen for each ton produced, based on a 2500-t/d methanol plant. Methanol demand is expected to increase in response to an increased use of the fuel—oxygenate methyl /-butyl ether (MTBE). 

U.S. methanol production in 1993 amounted to 4 8 Mt, but demand possibly exceeded 8 Mt, the difference being met by imports. The increased production of MTBE (methyl /-butyl ether, see section 12.9.3) appears to have consumed some 4Mt of methanol, compared with l 45Mt for formaldehyde (1-3 Mt, 100% bases) and possibly 0 7-0 8Mt for the carbonylation routes to acetic acid anhydride. (Amino-, phenolic- and polyacetal-resins accounted for 27%, 22% and 12% of formaldehyde use respectively, and C4 diols about 12%.)... 

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). 

The process gas of ethylene plants and methyl tertiary butyl ether plants is normally a hydrogen/ methane mixture. The molecular weight of the gas in such processes ranges from 3.5 to 14. The tliermodynamic behavior of hydrogen/methane mixtures has been and continues to be extensively researched. The gas dynamic design of turboexpanders, which are extensively used in such plants, depends on the equations of state of the process gas. Optimum performance of the turboexpander and associated equipment demands accurate thermodynamic properties for a wide range of process gas conditions. 

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. 

For the determination of vitamin E in seed oils by HPLC, the oils can simply be dissolved in hexane and analyzed directly. Solid-food samples demand a more rigorous method of solvent extraction. In a modified Rose-Gottlieb method to extract vitamin E from infant formulas (86), dipotassium oxalate solution (35% w/v) was substituted for ammonia to avoid alkalizing the medium, and methyl tert-butyl ether was substituted for diethyl ether because of its stability against the formation of peroxides. 

The /-butyl alcohol can be used to increase the octane number of unleaded gasoline or it can be made into methyl t-butyl ether (MTBE) for the same application. The alcohol can also be dehydrated to isobutylene, which in turn is used in alkylation to give highly branched dimers for addition to straight-run gasoline. An alternative reactant in this method is ethylbenzene hydroperoxide. This eventually forms phenylmethylcarbinol along with the propylene oxide, and the alcohol is dehydrated to styrene. Thus, the yield of the by-product can be varied depending on the demand for substances such as /-butyl alcohol or styrene. 

Conventional uses of methanol account for 90% of present consumption and include formaldehyde, dimethyl terephthalate, methyl methacrylate, methyl halides, methylamines and various solvent and other applications. Newer uses for methanol that have revitalized its growth and outlook include a new technology for acetic acid, single cell protein, methyl tertiary butyl ether-(MTBE), and water denitrification. Potential uses for methanol include its use as a carrier for coal in pipelines, as a source of hydrogen or synthesis gas used in direct reduction of iron ore, as a direct additive to or a feedstock for gasoline, peak power shaving and other fuel related possibilities. Table II lists the world methanol demand by end use in 1979. 

Methanol, also known as wood alcohol, is another widely discussed potential source (or carrier) of hydrogen.31 Chemically, methanol, ch oh, is a clear liquid, the simplest of the alcohols, with one carbon atom per molecule. Methanol is extensively used today— U.S. demand in 2002 exceeded 2 billion gallons. The largest U.S. methanol markets are for producing the gasoline additive mtbe (methyl tertiary butyl ether) as well as formaldehyde and acetic acid. 

In the isobutane process the f-butanol (TBA) co-product is converted to the gasoline additive, methyl t-butyl ether (MTBE), via dehydration to isobutene and reaction with methanol. The theoretical weight ratio of TBA/PO is 1.32 1 but commercial plants produce 2-3 kg TBA per kg, depending on demand. Because of the very large gasoline pool, marketing 2-3 kg of TBA per kg PO is not a problem. 

Traditional demand for methanol is fairly limited. Apart from its use as a solvent and as a feedstock for the production of formaldehyde and acetic acid, the use of methanol is not growing in demand significantly. Because of unrelated concerns with ground water contamination in the U.S.A. and a few other countries, MTBE (methyl tert-butyl ether), one of the fastest growing outlets for methanol in recent years, has slowed down to almost a halt. Currently, the principal momentum behind the renewed interest in methanol production resides in its application in non-traditional areas. These can be summarized as follows ... 

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. 

For the foreseeable future, methyl tertiary butyl ether is expected to provide for the greatest demand for methanol (unless the MTBE is banned from gasoline). Utilization of methanol directly as automotive fuel has not found strong support except in specialized uses such as racing vehicles. However, research is progressing to develop other uses for methanol. Potentially large new markets for methanol may be the following ... 

The environment in chemical tanks is amongst the severest to which marine coatings are subjected. Each tank may have to transport some 1500 bulk, liquid cargoes that include crude oil, refined gasoline, aviation spirit, diesel oil, solvents, vegetable oils, or wine. Inorganic cargoes are also carried in solution (e.g., alkalis and acids). New demands also appear such as methanol as a fuel and feedstock, and methyl rert-butyl ether as an additive for lead-free petrol. 

Over the last decade reactive distillation (RD) has become a key technology for meeting increased productivity demands. The best-known example in C4 chemistry is given by MTBE (methyl tert butyl ether) synthesis. Both the CD Tech process and the Ethermax process by UOP consist of fixed-bed reactors followed by an RD col-... 

Carbon monoxide and ozone levels are in excess of the National Ambient Air Quality Standards in the Northeastern states, which constitute a corridor from Virginia to New England. The principal source of carbon monoxide are emissions from automobiles. The coalition of Northeastern regulators have mandated cleaner burning fuels for the region however, demand is uncertain since the member states can opt into the plan until 1995. The use of methyl-tert-butyl-ether (MTBE) as an octane enhancer provides significant reductions in carbon monoxide emissions. 

With the notable exception of sulphuric acid, the most important chemical of all (and to a much smaller degree phosphoric acid and urea), which suffered a significant decrease, all the other chemicals achieved an increase in 1993 compared with 1988. The most spectacular increase goes to methyl r-butyl ether (MTBE) which was way down the list in 1988 but is now 9th and climbing. Demand for this is increasing enormously because it is used instead of tetraethyl lead to increase the octane rating of unleaded petrol. 

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