Question

For each compound, provide a name if the structure is given, or provide a structure if the name is given. (a) butyl ethyl ether (b) \(\mathrm{H}_{3} \mathrm{C}-\mathrm{CH}_{2}-\mathrm{O}-\mathrm{CH}_{2}-\mathrm{CH}_{3}\) (c) CCCCOCCCC (d) ethyl hexyl ether

Short answer

a) Butyl ethyl ether is an ether with one butyl and one ethyl group attached to oxygen. b) The compound is diethyl ether. c) The compound is dibutyl ether. d) Ethyl hexyl ether consists of an ethyl group and a hexyl group connected by an oxygen atom.

Step-by-step solution

- Naming Butyl Ethyl Ether

Identify the two alkyl groups attached to the ether oxygen. The names of the alkyl groups are derived from the number of carbons they contain. In this case, the name 'butyl' indicates a four-carbon alkyl group and 'ethyl' indicates a two-carbon alkyl group.

- Drawing the Structure for H3C-CH2-O-CH2-CH3

Identify that the given structure corresponds to an ether, with two alkyl groups on either side of an oxygen atom. Count the number of carbons in each alkyl group and name them accordingly. The left side has two carbons (ethyl-) and the right side has two carbons as well (ethyl-), so the compound is diethyl ether.

- Naming the Compound for CCCCCOCCCC

Read the SMILES notation and determine the structure it represents. The letters 'C' represent carbon atoms and 'O' is for oxygen. Since oxygen is flanked by a total of eight carbons (four on each side), we can split them into two groups leading to 'butyl' (four carbons) on one side and 'butyl' on the other side. The compound is butyl butyl ether, or more commonly called dibutyl ether.

- Drawing the Structure for Ethyl Hexyl Ether

Identify the length of the carbon chains for 'ethyl' and 'hexyl'. 'Ethyl' indicates a two-carbon alkyl group and 'hexyl' indicates a six-carbon alkyl group. Connect these alkyl groups with an oxygen atom between them to complete the structure of the ether.

Key concepts

Alkyl Group Naming

Understanding the naming of alkyl groups is foundational in organic chemistry. An alkyl group is derived from an alkane by removing one hydrogen atom, giving it an open valence. They are typically used as substituents in organic compounds, and their names are based on the number of carbon atoms they contain.

For example, a one-carbon alkyl group is called 'methyl', a two-carbon group is 'ethyl', three carbons make a 'propyl' group, and a four-carbon chain is named 'butyl'. These are just the simplest examples; more complex branches are also named according to their carbon content and structure. Additionally, prefixes like 'iso-' and 'sec-' inform about variations in the carbon chain branching. For instance, 'sec-butyl' represents a butyl group where the substituent is connected to the second carbon rather than the first.

When naming ethers, as shown in the exercise solutions, recognizing the alkyl groups attached to the oxygen atom is crucial. In the case of butyl ethyl ether, the name signifies one butyl group (four carbons) and one ethyl group (two carbons). Knowing these basics helps students name more complex molecular structures confidently.

Ether Structure

Ethers are a class of organic compounds characterized by an oxygen atom connected to two alkyl or aryl groups. The general formula for an ether is R-O-R', where 'R' and 'R' can be the same or different alkyl or aryl groups.

In the solutions provided, we encounter butyl ethyl ether and diethyl ether. The key feature of these structures is the oxygen atom linking two carbon chains. Ethers are known for their distinct physical and chemical properties – for example, they are relatively inert and have low boiling points, making them excellent solvents. Their simplicity in structure often leads to straightforward naming as you connect the names of the two side chains with the term 'ether'. It should be noted that in a symmetrical ether, such as diethyl ether, the same alkyl group name is repeated. However, in unsymmetrical ethers like ethyl hexyl ether, we specify both chains separately as they vary in length.

SMILES Notation

The Simplified Molecular Input Line Entry System (SMILES) is a notation that allows chemists to represent a chemical structure in a linear textual form. This is particularly useful in computational chemistry for database searching and molecular modeling.

SMILES strings consist of letters and symbols that denote atoms and their connectivity. Each 'C' represents a carbon atom, while an 'O' stands for oxygen, other elements are represented by their chemical symbols, and single bonds are implied when not stated otherwise. For instance, 'CCCCOCCCC' represents an ether compound (dibutyl ether) where an oxygen atom is flanked by two butyl groups.

Learning SMILES notation may seem daunting at first, but with practice, students can quickly interpret and convert these strings into actual chemical structures. The notation tells us not only about the types of atoms present but also provides insight into the molecular geometry and sometimes even stereochemistry, with additional symbols for double bonds, branches, and rings.