Aim # 42: How do we name molecules with functional groups- part 1? H.W. # 42 Study pp. 660-667 Ans. ques. p. 679 # 39a,b,c; 40-42; 43c,d; 48;49;50a,b,d; 51b,d Do Now: Name the following molecules:

Review: Alkenes and Alkynes We know from the last lesson that: Alkenes and alkynes have similar naming system to alkanes. Prefix + “-ene” for alkenes Prefix + “-yne” for alkynes One must indicate the carbon tha tht double/triple bond starts with. Branched alkenes/alkynes followo the same rules, but carbon numbering comes from the multiple bond.

Functional Groups- what are they? Turn to Reference Table R- Functional Groups. What does each column represent? What do you think you would use this table for? Is there a naming system you can identify for one of these rows?

Functional Groups, cont’d A functional group is a group of bonded atoms in an organic molecule that determine the molecule’s properties. For example, all molecules with an –OH group are alcohols, and have the physical and chemical properties of alcohols (solubility in water, reactivity with organic acids, etc.)

Functional Groups and Naming Each type of functional group has: A characteristic group of bonded atoms; Typical physical and chemical properties; and Its own naming system. The naming is the most important part of this topic for the Regents Exam. We will also discuss the reactivity of some functional groups later this week.

Functional Group #1: Halides Halides are the halogens (F,Cl,Br,I) attached to a carbon as a side group. Examples of Halides are : Chlorofluorocarbons (CFCs), formerly used in aerosol cans. Halons, use to extinguish fires. We already know the naming system- we learned it last week.

Functional Group # 2: Alcohols An alcohol is a molecule with the hydroxyl (-OH) group attached to a carbon. Three types: Primary alcohol- attached carbon is linked to one (1) other carbon Secondary alcohol- attached carbon is linked to two (2) other carbons. Tertitiary alcohol- attached carbon is linked to three (3) other carbons

Naming Alcohols 1. Select the longest chain of carbon atoms containing the –OH functional group. 2. Number the carbons so that the –OH receives the smallest number. 3. Replace the - e from the hydrocarbon root name with – ol. 4. Name all other side groups as normal, indicating the number of each, the number of each carbon etc.

Alchol naming examples 1-propanol 2-propanol 3-pentanol 3-methyl-2-pentanol

Functional Group #3: Ethers Ether – a compound with an oxygen atom joining two carbon atoms. Used in the 19th century as a surgical anesthetic. “Epoxy” products have cyclic ethers.

Naming Ethers To name an ether: 1. Identify the hydrocarbon groups on each side of the oxygen. 2. Write the names of the two groups, in alphabetical order. 3. Add the word, ‘ether.’

Ethereal Examples Ethyl methyl ether Dimethyl ether Methyl propyl ether Dipropyl ether

Functional Groups #4 and #5: Aldehydes and Ketones The next two fucntional groups, aldehydes and ketones, both have a carbon-oxygen double bond (a carbonyl group). Aldehydes have the carbonyl group at the end of the carbon chain. Ketones have the carbonyl group in between two carbons.

Identifying and Naming Aldehydes If you see a carbon double-bonded to an oxygen at the end of a carbon chain, the molecule is an aldehyde. “Aldehydes are at the end!” Aldehyde naming: 1. Take the –e off the hydrocarbon root name. 2. Add ‘-al.’ 3. C=O gets priority for carbon numbering.

Aldehyde Examples Propanal 3-butanal 3-methybutanal

Identifying and naming ketones If you see a carbon double-bonded to an oxygen in the middle of a carbon chain, then you have a ketone. Ketone Naming: 1. Take the –e off the hydrocarbon root name. 2. Add –one. 3. Indicate the # of the carbon with the oxygen. 4. C=O gets priority for carbon numbering.

Ketone Examples 2-propanone 2-pentanone 3-pentanone Could you ever have a molecule named 1-propanone? Why or why not?