3.3.2 Benzene, toluene and xylene

In addition to benzene itself, the catalytic reformer also produces ethylbenzene, toluene and the isomeric xylenes directly. The demand for ethylbenzene is always great as a source of styrene monomer, but toluene does not find great use apart from a relatively small application in polyurethane. This is why most toluene is de-alkylated to increase overall benzene production. A similar problem exists with the xylenes:

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3.3.1 Ethylene, propylene and butadiene

Nowadays ethylene is the most important building block for the chemical industry, particularly as a monomer in its own right, as a co-monomer with other vinyls, and as a source of vinyl monomers. It is the prime source for ethylene oxide, which is another major source of polymers, glycols and ethers. They can also be used to build up more complex C4 molecules and aromatics.

Some of the ways in which the ethylene molecule is modified to create other chemicals and polymers are
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3.3 Petrochemical intermediates and monomers

About 80 per cent of all petrochemicals end up in polymers, the most important building blocks being ethylene, propylene, butadiene and benzene. The first three can be polymerized directly but an important slice of their production is used to create more complex monomers. Ethylene is the progenitor of most vinyl monomers (Figure 35), so the pressure on ethylene supply is particularly strong compared for example to propyle
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3.2.2 Ethane cracking

Although ethane can be cracked thermally, the reaction is slow and does not necessarily yield ethylene at high severity. Careful control of reaction conditions, however, allows the reaction to occur

The yield of ethylene is typically nearly 50 wt% with the rest composed of unreacted ethane (40 per cent) and some methane and hydrogen (10 per cent). T
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3.2.1 Thermal cracking

The bulk of the major monomer and intermediate, ethylene (C2H4), is still produced in the UK by steam cracking without the use of catalysts. Paraffinic feedstocks are best for optimising ethylene yields, and the severity of cracking is specified by the rate of disappearance of a marker compound, usually n-pentane. The severity of the reaction can then be defined as follows:

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1 Learning to learn
How do we learn? Understanding ‘how’ is the key to learning more effectively. This unit looks at the three main categories of theories: the acquisitive, constructivist and experiential models of learning. There is no right way to learn but developing an active approach will ensure that you are open to new ideas.
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2.3 Choosing your voice: exercise
In this unit we will consider how language can be used in different ways for different purposes. To do this we will use the theme of memorial and commemoration. In the first section we briefly discuss the life of the poet Siegfried Sassoon before examining both his poetry and prose. Through this we will see how he conveys meaning in different ways for different audiences using different forms. Following this we discuss more generally how different meanings can be conveyed using prose and poetic
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9.8 Debate 5: the novel today
Sunset Song was written in the early 1930s and is still one of the best-known and most-debated Scottish novels. In this unit, we discuss whether Sunset Song succeeds as critique of capitalism and whether it has value as a work of literature separate from its propagandistic ambitions.
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8.7.1 Summing up
Sunset Song was written in the early 1930s and is still one of the best-known and most-debated Scottish novels. In this unit, we discuss whether Sunset Song succeeds as critique of capitalism and whether it has value as a work of literature separate from its propagandistic ambitions.
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Biographers' Club Award
Wendy Moffat, professor of English at Dickinson College, received the Biographers' Club Best First Biography Prize for her book "A Great Unrecorded History."
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Multiplying complex numbers
This animation shows how to multiply complex numbers, using a simple example
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Debits and Credits - Accounting
The difficulty with accounting has less to do with the math, as it does with its concepts. Now, there is no more difficult yet vital concept to understand than that of Debits and Credits. Debits and Credits are at the very heart of the 'double entry bookkeeping' that has been the foundation stone on which the financial world's accounting system has been built for well over 500 years. Now, given the length of time, is it any wonder that confusion has surrounded the concept of Debits and Credits
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5.3 Neighbourhoods
Surfaces are a special class of topological spaces that crop up in many places in the world of mathematics. In this unit, you will learn to classify surfaces and will be introduced to such concepts as homeomorphism, orientability, the Euler characteristic and the Classification Theorum.
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Frontiers in Biomedical Engineering
The course covers basic concepts of biomedical engineering and their connection with the spectrum of human activity. It serves as an introduction to the fundamental science and engineering on which biomedical engineering is based. Case studies of drugs and medical products illustrate the product development-product testing cycle, patent protection, and FDA approval. It is designed for science and non-science majors.
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Open Wide and Trek Inside
Open Wide and Trek Inside has several objectives. The first is to help students understand major concepts related to oral health. By focusing on the science of the oral environment, the module goes beyond the traditional "brushing and flossing" curriculum and presents to students the ways science has helped people understand how to take proper care of their mouths and the structures within. The second objective of the module is to engage students in the nature of science through inquiry. As st
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Nalaganje pripravljenje simulacije
Opis poteka zagona in spremljanja simulacije v okolju JxyZET.,How to start and monitor the simulation in the JxyZET.
Author(s): Hermann Härtel

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Math Objects
The paper discusses mathematical form generation as an academic methodology to develop new approaches to architectural design. The academic design studio ?Math objects? investigates the relationship between complex 3d-surfaces and mathematics in order to expand the formal repertoire of architecture. It claims that the process of form generation can be seen as an autonomous entity, which is independent from an overall strategy or any a priori meaning. Architecture has always originated from a co
Author(s): Baerlecken, Daniel; Kobiella, Olaf

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