Naming organic compounds alkanes

The alkanes are a class of hydrocarbons in which the atoms are connected by single bonds. One of the most common uses of alkanes is as fuels. Methane, used in gas heaters and gas cooktops, is an alkane with one carbon atom. The alkanes ethane, propane, and butane contain two, three, and four carbon atoms, respectively, connected in a row or a continuous chain. As we can see, all the names for alkanes end in ane. Such names are part of the lUPAC (International Union of Pure and Applied Chemistry) system used by chemists to name organic compounds. Alkanes with five or more carbon atoms in a chain are named using the prefixes pent (5), hex (6), kept (7), oct (8), non (9), and dec (10) (see Table 6.14). 

The International Union of Pure and Applied Chemistry (lUPAC) has set standard rules for naming organic compounds. The systematic (or lUPAC) names of alkanes and most other organic compounds follow the same pattern, shown below. 

The IUPAC system for naming organic compounds is very logical and thorough. The rules for naming alkanes are the basis for naming the other organic compounds that you will study. Therefore it is important that you understand how to name alkanes. 

Because there are literally millions of organic compounds, it would be impossible to remember common names for all of them. Just as we did in Chapter 4 for inorganic compounds, we must learn a systematic method for naming organic compounds. We will first consider the principles applied in naming alkanes and then summarize them as a set of rules. 

Okay. You re ready to throw down this book in disgust, aren t you I know the alkane naming system sounds ridiculous, but it s really much easier than it looks. In fact, most of my students find that naming organic compounds is one of the most fun things to do in organic chemistry. 

The lUPAC system for naming organic compounds extends to the naming of alkenes by stipulating how to indicate the position of the double bond in the chain. The basic names of the alkenes are assembled as for the alkanes, except that the names end in -ene rather than -ane. A fifth step needs to be added to those we identified before so that we can indicate the position in the chain of the C=C double bond ... 

D Write, recognize, or otherwise identify (a) the structural unit, or functional group, (b) the general formula, and (c) the molecular or structural formulas and/or names of specific examples of the following classes of organic compounds alkanes, alkenes, alkynes, cycloalkanes, aromatic hydrocarbons, alcohols, ethers, aldehydes, ketones, carboxylic acids, esters, amines, and amides. 

Alkanes are relatively unreactive and are rarely involved in chemical reactions, but they nevertheless provide a useful vehicle for introducing some important general ideas. In this chapter, we ll use alkanes to introduce the basic approach to naming organic compounds and to take an initial look at some of the three-dimensional aspects of molecules, a topic of particular importance in understanding biological organic chemistry. 

First we will see how alkanes are named because their names form the basis for the names of all other organic compounds. Alkanes are composed of only carbon atoms... 

Straight-chain alkanes are named according to the number of carbon atoms they contain, as shown in Table 3.3. With the exception of the first four compounds—methane, ethane, propane, and butane—whose names have historical roots, the alkanes are named based on Greek numbers. The suffix -one is added to the end of each name to indicate that the molecule identified is an alkane. Thus, pentane is the five-carbon alkane, hexeme is the six-carbon alkane, and so on. We ll soon see that these alkane names form the basis for naming all other organic compounds, so at least the first ten should be memorized. 

As we cover new functional groups in later chapters, the applicable IUPAC rules of nomenclature will be given. In addition, Appendix A at the back of this book gives an overall view of organic nomenclature and shows how compounds that contain more than one functional group are named. For the present, let s see how to name branched-chain alkanes and learn some general naming rules that are applicable to all compounds. 

As organic chemistry developed, it became apparent that some systematic way of naming compounds was needed. About 70 years ago, the International Union of Pure and Applied Chemistry (IUPAC) devised a system that could be used for all organic compounds. To illustrate this system, we will show how it works with alkanes. 

The alkane series is also called the saturated hydrocarbon series because the molecules of this class have carbon atoms connected by single bonds only, and therefore have the maximum number of hydrogen atoms possible for the number of carbon atoms. These substances may be represented by the general formula C H2,I + 2 and molecules of successive members of the series differ from each other by only a CH2 unit. The line formulas and names of the first 10 members of the series, given in Table 21-2, should be memorized because these names form the basis for naming many other organic compounds. It should be noted that the first parts of the names of the later members listed are the... 

In this section, you reviewed how to name and draw alkanes, alkenes, and alkynes. You also learned how to name aromatic hydrocarbons. The names of all the other organic compounds you will encounter in this unit are based on the names of hydrocarbons. In the next section, you will learn about organic compounds that have single bonds to halogen atoms, oxygen atoms, and nitrogen atoms. 

Like the other organic compounds you have encountered, the names of aldehydes and ketones are based on the names of the parent alkanes. 

The nomenclature of the alcohols is an extension of the rules for the naming of other organic compounds. The general changes in the rules for alkanes are... 

In general, organic compounds are given systematic names by using the order prefix-parent-suffix, where prefix indicates how many branching groups are present, parent indicates how many carbons are in the longest chain and suffix indicates the name of the family. Common names as weU as systematic names are used for alkanes and their derivatives. However, it is advisable to use systematic names or the lUPAC (International Union of Pure and Applied Chemistry) nomenclature, which can be derived from a simple set of rules. 

The simplist organic compounds are branched or unbranched chains of C atoms to which H atoms have become attached and in which each C atom is bound to four other atoms. This family is called alkanes and the names of the unbranched compounds serve as a basis for the nomenclature of other organic chain compounds. 

Most organic compounds can be derived from alkanes. In addition, many important parts of organic molecules contain one or more alkane groups, minus a hydrogen atom, bonded as substituents onto the basic organic molecule. As a consequence of these factors, the names of many organic compounds are based on alkanes. It is useful to know the names of some of the more common alkanes and substituent groups derived from them, as shown in Table 1.3. 

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