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Propylene oxide is an organic compound with the molecular formula CH3CHCH2O. This colourless volatile liquid is produced on a large scale industrially, its major application being its use for the production of polyether polyols for use in making polyurethane plastics. It is chiral epoxide, although it commonly used as a racemic mixture.

This compound is sometimes called 1,2-propylene oxide to distinguish it from its isomer 1,3-propylene oxide, better known as oxetane.

Co-oxidation of propylene

The other general route to propylene oxide involves co-oxidation of the organic chemicals isobutane or ethylbenzene. In the present of catalyst, air oxidation occurs as follows:

CH3CH=CH2 + Ph-CH2CH3 + O2 → CH3CHCH2O + Ph-CH=CH2 + H2O

The coproducts of these reactions, t-butyl alcohol or styrene, are useful feedstock for other products. For example, t-butyl alcohol reacts with methanol to give MTBE, an additive for gasoline. Before the current ban of MTBE, propylene/isobutane was one of the most important production process.

Oxidation of propylene

In April 2003, Sumitomo Chemical commercialized the first PO-only plant in Japan, which produces propylene oxide from oxidation of cumene without significant production of other products.[2] This method is a variant of the POSM process (co-oxidation) that uses cumene hydroperoxide instead of ethylbenzene hydroperoxide and recycles the coproduct (alpha-hydroxycumene) via dehydration and hydrogenation back to cumene.

In March 2009, BASF and Dow Chemical started up their new HPPO plant in Antwerp.[3] In the HPPO-Process, propylene is oxidized with hydrogen peroxide:

CH3CH=CH2 + H2O2 → CH3CHCH2O + H2O

In this process no side products other than water are generated.[4]

METHANOL

Carbon monoxide and hydrogen react over a catalyst to produce methanol. Today, the most widely used catalyst is a mixture of copper, zinc oxide, and alumina first used by ICI in 1966. At 5–10 MPa (50–100 atm) and 250 °C, it can catalyze the production of methanol from carbon monoxide and hydrogen with high selectivity (>99.8%):

CO + 2 H2 → CH3OH

It is worth noting that the production of synthesis gas from methane produces three moles of hydrogen gas for every mole of carbon monoxide, while the methanol synthesis consumes only two moles of hydrogen gas per mole of carbon monoxide. One way of dealing with the excess hydrogen is to inject carbon dioxide into the methanol synthesis reactor, where it, too, reacts to form methanol according to the equation:

CO2 + 3 H2 → CH3OH + H2O

Some chemists believe that the certain catalysts synthesize methanol using CO2 as an intermediary, and consuming CO only indirectly.

CO2 + 3 H2 → CH3OH + H2O

where the H2O byproduct is recycled via the water-gas shift reaction

CO + H2O → CO2 + H2,

This gives an overall reaction, which is the same as listed above.

CO + 2 H2 → CH3OHButadiene

1,3-Butadiene is a simple conjugated diene with the formula C4H6. It is an important industrial chemical used as a monomer in the production of synthetic rubber. When the word butadiene is used, most of the time it refers to 1,3-butadiene.

The name butadiene can also refer to the isomer, 1,2-butadiene, which is a cumulated diene. However, this allene is difficult to prepare and has no industrial significance. This diene is also not expected to act as a diene in a Diels–Alder reaction due to its structure. To effect a Diels-Alder reaction only a conjugated diene will suffice.

Butadiene can also be produced by the catalytic dehydrogenation of normal butane (n-butane). The first such post-war commercial plant, producing 65,000 tons per year of butadiene, began operations in 1957 in Houston, Texas.[4] Prior to that, in the 1940s the U. S. War Department constructed several plants in Borger, TX, Toledo, OH, and El Segundo, CA to produce synthetic rubber for the war effort as part of the United States Synthetic Rubber Program.[5] Total capacity was 68 KMTA (Kilo Metric Tons per Annum).

Today, butadiene from n-butane is commercially practiced using the Houdry catadiene process, which was developed during WWII.

Odefins

This reaction was first used in petroleum reformation for the synthesis of higher olefins (Shell higher olefin process - SHOP), with nickel catalysts under high pressure and high temperatures. Nowadays, even polyenes with MW > 250,000 are produced industrially in this way.

Synthetically useful, high-yield procedures for lab use include ring closure between terminal vinyl groups, cross metathesis - the intermolecular reaction of terminal vinyl groups - and ring opening of strained alkenes. When molecules with terminal vinyl groups are used, the equilibrium can be driven by the ready removal of the product ethene from the reaction mixture. Ring opening metathesis can employ an excess of a second alkene (for example ethene), but can also be conducted as a homo- or co-polymerization reaction. The driving force in this case is the loss of ring strain.

All of these applications have been made possible by the development of new homogeneous catalysts. Shown below are some of these catalysts, which tolerate more functional groups and are more stable and easy to handle

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