Hydrocarbon functional groups alkynes

As each functional group is discussed in future chapters, the spectroscopic properties of that group will be described. For the present, we ll point out some distinguishing features of the hydrocarbon functional groups already studied and briefly preview some other common functional groups. We should also point out, however, that in addition to interpreting absorptions that ore present in an IR spectrum, it s also possible to get structural information by noticing which absorptions are not present. If the spectrum of a compound has no absorptions at 3300 and 2150 cm-1, the compound is not a terminal alkyne if the spectrum has no absorption near 3400 cm -, the compound Is not an alcohol and so on. 

In our study of the simple hydrocarbons, there are only two functional groups. One is a carbon-to-carbon double bond. Hydrocarbons that contain a carbon-to-carbon double bond are alkenes. The other hydrocarbon functional group is a carbon-to-carbon triple bond. Hydrocarbons that contain a triple bond are alkynes. These functional groups are the reactive sites in the alkenes and alkynes. The result is that alkenes and alkynes are more reactive than the alkanes. 

Hydrocarbons contain only hydrogen and carbon. The hydrocarbon functional groups include alkanes, alkenes, alkynes, and arenes (aromatic compounds). Simple hydrocarbons have few medicinal applications, but are the feedstock of the petrochemical industry to produce plastics, dyes, solvents, detergents, and adhesives (to name just a few). Therefore, hydrocarbons are essential to the medical field. Additionally, all hydrocarbons are flammable and, therefore, find application as fuels. For example, gasoline is a mixture of hydrocarbons. 

Alkynes are hydrocarbons with carbon-carbon triple bonds as their functional group. Alkyne names generally have the -yne suffix, although some of their common names (acetylene, for example) do not conform to this rule. The triple bond is linear, so there is no possibility of geometric (cis-trans) isomerism in alkynes. 

When certain atoms are collected into discrete units, they have special physical and/or chemical properties. Such units are known as functional groups. The C=C unit of alkenes and the C=C unit of alkynes are examples of hydrocarbon functional groups. The C-C unit of an alkane is not considered to be a functional group because it is the backbone of virtually all organic molecules. Functional groups can include atoms other than carbon or hydrogen and the presence of these other atoms (call them heteroatoms) leads to new functional groups. 

This chapter will build on principles introduced in previous chapters and show applications to common chemical reactions of two important hydrocarbon functional groups alkenes and alkynes. The chapter will also introduce several new chemical reagents (compounds that react with an alkene or alkyne to give a new molecule), as well as several new types of reactions. The theme of acid-base chemistry will be used as a basis for understanding each chemical transformation where it is appropriate. Mechanisms that are the step-by-step processes by which one molecule is transformed into another by tracking the intermediates will also be discussed. The concept of mechanism was introduced in Chapter 7 (Section 7.8). 

Hydrocarbons that contain a carbon-carbon triple bond are called alkynes Non cyclic alkynes have the molecular formula C H2 -2 Acetylene (HC=CH) is the simplest alkyne We call compounds that have their triple bond at the end of a carbon chain (RC=CH) monosubstituted or terminal alkynes Disubstituted alkynes (RC=CR ) have internal triple bonds You will see m this chapter that a carbon-carbon triple bond is a functional group reacting with many of the same reagents that react with the double bonds of alkenes... 

Alkynes are hydrocarbons that contain a carbon-carbon triple bond Sim pie alkynes having no other functional groups or rings have the general formula C H2 -2 Acetylene is the simplest alkyne... 

Functional Groups Defining Alkenes, Alkynes, and Aromatic Hydrocarbons... 

You first should decide what type of compound it is. The decision usually is straightforward for hydrocarbons, which will fall in one or the other of the categories alkanes, alkenes, alkynes, arenes, cycloalkanes, and so on. But when the compound has more than one functional group it is not always obvious which is the parent function. For example, Compound 1 could be named as an alkene (because of the double-bond function) or as an alcohol (because of the OH function) ... 

In the tables on the following pages, the symbols R and R represent hydrocarbons in covalent linkage to the functional group. Many derivatives are named in a similar manner to alkenes and alkynes, but the location and suffix of the functional group is used in place of -ene and -yne. 

Halides are second only to carboxylic acids in their versatility in organic synthesis. Functional group transformations into alkenes, alkynes, amines, aldehydes, alcohols, ethers, hydrocarbons, ketones and other groups may be performed with ease in high yield. However, the major synthetic importance of halides arises from the ease by which compounds that contain this functionality may be used in carbon-carbon bond-forming reactions and in the preparation of heterocyclic compounds. 

Define or identify each of the following terms (a) organic chemistry, (b) total bond order, (c) condensed formula, (d) structural formula, (e) fine formula, (/) hydrocarbon, (g) alkane, (h) aUcene, (/) alkyne, j) aromatic hydrocarbon, (k) saturated, (1) delocalized double bond, (m) isomerism, (n) cycloalkane, (o) radical, (p) functional group, (q) alcohol, (r) ether, (s) aldehyde, (f) ketone, (u) carbonyl group, and (v) ester. 

Hydroalumination. The treatment of alkynes with diisobutylaluminum hydride in hydrocarbon solvents results in a aT-addition of the Al-H bond to the triple bond to produce stereodefined alkenylalanes. The hydroalumination of alkynes is more limited in scope than the corresponding hydroboration reaction of alkynes (see Chapter 5) with regard to accommodation of functional groups and regioselectivity. Whereas hydroalumination of 1-alkynes is highly regioselective, placing the aluminum at the terminal position of the triple bond, unsymmetrically substituted alkynes produce mixtures of isomeric alkenylalanes. 

A Lewis acid catalyst can interact with the reagent containing a functional group having a donor atom with nonbonded pairs of electrons. This gives rise to a positively polarized complex or a carbocationic species, which then reacts with the -rr-donor substrate (aromatic, alkenic or alkynic hydrocarbons). Though this process can occur under strictly anhydrous conditions, this generally is not the case as impurity, moisture, or other cocatalysts are usually present. In the case of reactions of alkenes and alkynes... 

Inferring Explain why alkenes and alkynes contain functional groups but are not substituted hydrocarbons. 

Common functional groups in organic chemistry include alkanes, alkenes, alkynes, aromatic hydrocarbons, carboxylic acids, aldehydes, ketones, alcohols, ethers, amines. 

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