Structures of Alkanes

Draw structures of alkanes that meet the following descriptions ... 

The structure of alkanes can be difficult to establish as their KMR spectra are difficult to interpret. The stereochemistry as well as the structure of (34) was in doubt, but synthesis by three different routes established both. 

Your chemistry teacher will probably require you to draw structures of alkanes when given their names and require you to name alkanes when given their structures. If your teacher fails to make such requests, ask to see his credentials. You may be dealing with an impostor. 

Scheme 1.1 Synthesis and structures of alkane- and alkyne-bridged nisin mimics [36].

Naming and Drawing Structures of Alkanes, Alkenes, and Cycloalkanes (page 161) Coached Tutorial Problem... 

What do steroids have to do with hydrocarbons Steroids are unsaturated compounds. Although they are complex organic molecules, their basic structure centres on four rings of carbon atoms. In other words, steroids are built around ring structures of alkanes and alkenes. 

Let s now take a closer look at the three-dimensional structure of alkanes. The study of three-dimensional structure is called stereochemistry. In Chapter 4 we examine the effect of rotation around single bonds. In Chapter 5, we will learn about other aspects of stereochemistry. 

Burda, J. Kuras, M. Kfiz, J. Vodicka, L. Relationship between retention behaviour and molecular structure of alkanes in reversed-phase high-performance liquid chromatography. Fresenius Z. Anal. Chem. 1985, 321, 549-552. 

Problem 3.10 Draw structures of alkanes that meet the following descriptions (a). An alkane with two tertiary carbons I (b) -An alkane that contains an isopropyl group (c). An alkane that has one quaternary and one secondary carbon... 

The pattern of bond lengths obtained by quantum chemical (QC) methods is almost identical for all of the alkanes and alkyl moieties given. The structures of alkanes are always easily predicted (see CH4 above) i.e. the vertical spread of points in the diagrams is always less than for the X-X... 

Under reactive experimental conditions in smog chamber investigations (12, 25), alkanes give substantial amounts of oxidant. However, while Table III reveals that saturated hydrocarbons give about as much oxidant as many aromatics, there again is no evident correlation between oxidant production and the chemical structure of alkanes. 

Describe how the molecular structures of alkenes and alkynes differ from the structure of alkanes. 

The approach is based on the well known electronic structure of alkanes and alkenes. The difference in the See energy is called the parameter of specific inleiactions, 6. It represents the average number and strength of the acidic centers present on the carbon surface [319, 320]. More positive it is, more acidic is tte surface of carbon. 

Bearing this shape in mind, it is possible to write the structural formula in an even simpler form. The figure below shows the structures of alkanes, their simplified structural formulas as well as their condensed structural formulas. 

It is interesting to mention that there is a correlation between the molecular structures of alkanes and some of their physical properties. By correlating the number of carbon atoms in simple alkanes with the melting points of the same compounds we observe that the molecules with odd numbers of C-atoms and those with even numbers of C-atoms exhibit different correlation curves. 

Looking at the structures of alkanes in the figure we can see that while the molecules with an odd number of carbon atoms appear symmetrical (both terminal carbon-carbon bonds being oriented upwards - black lines), where the structures with an even number are asymmetrical in the sense that the terminal carbon-carbon bonds are oriented upwards on the left end of the chain, but downwards on the right end (blue lines). Although the correct explanation is not simple, this example demonstrates how macroscopic properties correlate with microscopic structures. We can assume that odd molecules in the condensed state shall be packed differently from even molecules. 

Scheme 6.23 Proposed structures of alkane metathesis catalysts. ...

The Fundamental Structure of Alkanes Based on the sp" Hybrid Model... 

It is important to know the various methods used for drawing the structures of alkanes. Initially, focus on alkanes that have linear chains. This means that all of the carbon atoms are connected in a chain, with no branches. The alkane with a linear chain of four carbon atoms has the butane (see Section 4.3), and it... 

The Structure of Alkanes Constitutional Isomerism in Alkanes Nomenclature of Alkanes and the lUPAC System Cycloalkanes... 

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