Presentation on theme: "Organic Classes # 4 The next 4 functional groups of Table R Alcohols, ethers, aldehydes, and ketones."— Presentation transcript:
Organic Classes # 4 The next 4 functional groups of Table R Alcohols, ethers, aldehydes, and ketones
So far organic chem could be summarized this way… 1 Carbon 2 Carbon makes chains of 1 to 10 carbons long (in our class). 3 The bonds can be all single bonds (alkanes) 4 They could have a double bond (alkenes) 5 Or they could have a triple bond (alkynes). 6 We could add halogens to these three kinds of chains, making halocarbons. 7 Naming them requires us to name the base chain first (numbers for the double or triple bonds), 8 Then we enumerate the halogens by carbon number as necessary.
On table R we’ll notice that there is something called an “R” group. “R” can stand for any hydrocarbon, of any length. It could even stand in for just an “H” atom. It’s generic. For halocarbons, the general formula is R ― X Where R stands for any hydrocarbon, say a methane, or an ethane, or a propane. X stands for any halogen. Chloro-hydrocarbon could be R ― Cl
Today we will look into the alcohols, the ethers, the aldehydes + the ketones (not key tones) By the time we finish today you should be able to recognize what type of molecule you are looking at by its structural diagram, or condensed structural formula. You will be able to draw one from its name or formula as well. This will keep you busy. Alcohols According to table R, alcohols have an “–OH” group which is NOT a hydroxide. When the anion hydroxide is ionically bonded to a metal, that is an Arrhenius base. This is different. When the –OH group is bonded covalently to a hydrocarbon, it’s called a type of alcohol.
The general formula for alcohols are R ― OH Where R is any hydrocarbon that the ―OH group can bond onto.
Draw and name each alcohol molecule 1 carbon 2 carbon 3 carbon H H HOHmethanol The –OH really means –O–H But we abbreviate it and just “know” that the oxygen and hydrogen make a single covalent bond. It’s prettier that way. C
Draw and name each alcohol molecule 1 carbon 2 carbon 3 carbon H H HOHmethanol H HOHethanol H H H HOH 1-propanol 2-propanol H OH H H H H HH C CC CCCCC C
Draw and name each 5 carbon alcohol molecule that you can…
Draw and name each 5 carbon alcohol molecule that you can… H H H H H H H H H H H OH H H OH H H H OH H H 1-pentanol 2-pentanol 3-pentanol Name the base chain (count carbon atoms) Enumerate where the alcohol group is located. Alcohol names always end with an -anol suffix CCCCC CCCCC CCCCC
This is a list of ALL the alcohols in our class, none are missing. # names of the carbons alcohols 1 methanol 2 ethanol 3 1-propanol, 2-propanol 4 1-butanol, 2-butanol 5 1-pentanol, 2-pentanol, 3-pentanol 6 1-hexanol, 2-hexanol, 3-hexanol 7 1-heptanol, 2-heptanol, 3-heptanol, 4-heptanol 8 1-octanol, 2-octanol, 3-octanol, 4-octanol 9 1-nonanol, 2-nonanol, 3-nonanol, 4-nonanol, 5-nonanol 10 1-decanol, 2-decanol, 3-decanol, 4-decanol, 5-decanol
Ethers R-O-R’ Ethers are easy because they have a single atom of oxygen in the middle, and two different “R” groups, one left and one right. We need to introduce one more new thing now. Methane is CH 4 Ethane is CH 3 CH 3 Propane is CH 3 CH 2 CH 3 There is NO WAY to attach a methane to an oxygen, or an ethane, or propane, etc. But if we remove a hydrogen, we can attach what’s left of methane, or ethane, or propane.
Ethers are R―O―R’ which means that on either side of the ether there is a hydrocarbon chain, one to ten carbons long. But not the “whole” methane, or ethane, propane, butane, pentane, hexane, etc. Methane minus 1 hydrogen is called methyl Ethane minus 1 hydrogen atom is called ethyl Propane minus 1 hydrogen atom is called propyl Butane minus 1 hydrogen atom is called butyl. Then comes pentyl, hexyl, heptyl, octyl, nonyl, and decyl.
CH 3 ―O―CH 3 is methyl methyl ether but we say dimethyl ether CH 3 CH 2 ―O―CH 3 is ethyl methyl ether O C C H H H O C C H H H H H C
Draw these ethers… (H atoms optional) Butyl ethyl ether Pentyl methyl ether Heptyl hexyl ether O H H H H H O H H O H H H H H HH H H H CCCCCC CCC CC C CCCCCCCCCCCCC
Ethers always have at least 1 carbon on each side – the smallest ether is dimethyl ether. They are named alphabetically. They always have the last name ether. There is a mistake in your reference table, it shows “methyl ethyl” ether when really what’s showing is ethyl methyl ether. Really that’s the same only named backwards.
Aldehydes and Ketones we will examine together, since they are nearly the same thing, but they are located in different places. They both have a carbon atom double bonded to an oxygen atom Aldehydes are always at the end of a hydrocarbon chain, where the ketones are always in the middle of a chain. We will draw the 3 carbon aldehyde, and the 3 carbon ketone now
3 carbon aldehyde propanal 3 carbon ketone propanone H H O H HHC C C H O H H HHC CC CH 3 CH 2 CHO CH 3 COCH 3
Draw METHANAL (no such thing as methanone) Draw ETHANAL (no such thing as ethanone) Draw BUTANAL and 2-Pentanone Need at least 3 carbons to “be in the middle” of a chain of carbons. Ketones “start” at 3 or propanone.
Draw METHANAL (no such thing as methanone) Draw ETHANAL (no such thing as ethanone) Draw BUTANAL and 2-Pentanone Need at least 3 carbons to “be in the middle” of a chain of carbons. Ketones “start” at 3 or propanone. HH O C HH O C H H H H H O H H H H H H H H O H H H H H It’s the placement of that double bonded oxygen that makes these 2 different kinds of molecules. C C CC C CC CC C