Classifying Organic Compounds -- a qualitative approach -Background: According to the presence of their functional groups, organic compounds can be classified in different families and classes. Below is a summary of the different classes of organic compounds and some of their corresponding families: Class
Examples of Families
As
Strong organic acids: Carboxylic-acids, amino acids
Aw
Weak organic acids: enols, phenols
B
Anilines (a N with a phenyl), some ethers
Nm
Neutral compounds (in general with N or S)
N
Alkenes, Alkynes, Alcohols, Aldehydes, Ketones
I
Haloalkanes, Sat. HydroCarbs
Sa
Carboxylic acids
Sb
Amines
Sg
Aldehydes, Esters, Ketones
Below is a brief summarization of the different kinds of organic families:1
1
Name
Feature
Alkanes Alkyl Halides Alkenes Alkynes Aromatic Compounds Alcohols Thiols Ethers Thioethers Aldehydes Ketones Carboxylic acids Amines Amino Acids Carbohydrates Organometallics
Single bonds Halogen bonded to a carbon At least one C-C double bond At least one C-C triple bond Involving Benzene, Napthalene, Anthracene One OH-group at least One SH-group at least (in place of the oxygen) One C-O-C at least Like ethers but with S One –CH=O group C=O Containing a carboxyl group –COOH One N bonded to H or C One amino group (NH2) and a carboxyl – COOH Several –OH groups and a formyl/keto Ionic bonding between metal & carbon
Nelson Chem 12 & Organic Compounds (http://chemistry.uah.edu/Faculty/vogler/lecturenotes113/ch113-chapter2.pdf)
One qualitative chemical analysis method for determining the class that an unknown organic compound belongs to is through solubility procedural solubility testing. Also to be noted is that it is very important to determine the various classes of organic compounds if found to be organic or not for determining the appropriateness of locating the emplacement of Lunar research stations. Apparatus: Small-size test tubes Gloves Scale Knife / spatula Graduated cylinder VERY accurate pipette Litmus paper 5% NaOH, NaHCO3, HCl solutions 96% H2SO4 solution Water Diethyl Ether Observation table Procedure:2 1. Label each sample; take the sample and obtain smaller 25 mg portions for solubility testing purposes. 2. To test for water solubility: 25 mg of unknown compound are placed in small test tube with 0.75 mL of water being added in small quantities; test tube must be shaken after each addition of water. Record solubility of compound with water. If soluble proceed to test for Ether solubility, if insoluble proceed to test for NaOH solubility. 3. Ether solubility: follow instructions for step 2 using diethyl ether instead of water. If insoluble then it is a salt/amino (class S); if water & ether soluble then apply litmus-paper test a. Neutral -- Sg b. Blue -- Sb c. Red -- Sa 4. NaOH solubility (5% solution): follow instructions for step 2 but using 5% NaOH solution (in lieu of water). If soluble, proceed to test for 5% NaHCO3 solubility, otherwise skip to HCl solubility 5. NaHCO3 solubility (5% solution): follow instructions for step 2 but using the 5% NaHCO3 (in lieu of water). If soluble then, it is As; if insoluble, then it is Aw. 6. HCl solubility (5% solution): follow instructions for step 2 but using the 5% HCl solution (in lieu of water). If soluble, then classified as a class B (organic base; if insoluble then it is a neutral compound ( Nm) and proceed in this case to H2SO4 solubility.
2
Nelson Chem 12 & Organic Chemistry Qualitative Analysis (http://www.chemistry.ccsu.edu/glagovich/teaching/472/qualanal/qualanal.html)
7. H2SO4 (96% solution): follow instructions for step 2 but use 0.6 mL of H2SO4 solution (in lieu of 0.75 mL water). If soluble, then the compound is neutral (N-class) and if insoluble it is inert (I-class).
Process Diagram:
Observations (at least 10 should be sampled): Compound #:
(physical aspects)
Compound #: (physical aspects)
Compound #: (physical aspects)
Compound #: (physical aspects)
Compound #: (physical aspects)
Compound #: (physical aspects)
Solubility Test Water Ether NaOH NaHCO3 HCl H2SO4
Solubility Test
Result (Yes/No)
Result (Yes/No)
Water Ether NaOH NaHCO3 HCl H2SO4
Solubility Test Water Ether NaOH NaHCO3 HCl H2SO4
Solubility Test
Result (Yes/No)
Result (Yes/No)
Water Ether NaOH NaHCO3 HCl H2SO4
Solubility Test Water Ether NaOH NaHCO3 HCl H2SO4
Solubility Test
Water Ether NaOH NaHCO3 HCl H2SO4
Result (Yes/No)
Result (Yes/No)
Compound #: (physical aspects)
Compound #: (physical aspects)
Compound #: (physical aspects)
Compound #: (physical aspects)
Compound #: (physical aspects)
Compound #: (physical aspects)
Solubility Test Water Ether NaOH NaHCO3 HCl H2SO4
Solubility Test
Result (Yes/No)
Result (Yes/No)
Water Ether NaOH NaHCO3 HCl H2SO4
Solubility Test Water Ether NaOH NaHCO3 HCl H2SO4
Solubility Test
Result (Yes/No)
Result (Yes/No)
Water Ether NaOH NaHCO3 HCl H2SO4
Solubility Test Water Ether NaOH NaHCO3 HCl H2SO4
Solubility Test
Water Ether NaOH NaHCO3 HCl H2SO4
Result (Yes/No)
Result (Yes/No)
Compound #: (physical aspects)
Compound #: (physical aspects)
Compound #: (physical aspects)
Compound #: (physical aspects)
Solubility Test Water Ether NaOH NaHCO3 HCl H2SO4
Solubility Test
Result (Yes/No)
Result (Yes/No)
Water Ether NaOH NaHCO3 HCl H2SO4
Solubility Test Water Ether NaOH NaHCO3 HCl H2SO4
Solubility Test
Result (Yes/No)
Result (Yes/No)
Water Ether NaOH NaHCO3 HCl H2SO4
Anecdotal Observations (this includes changes to procedure, apparatus) • • • • • • • • • • • •
Discussion: 1. Before testing each compound form a hypothesis based on physical appearance and the results from the previous compounds. Refute/support the hypothesis. 2. Determine the general trend of the organic compound classification is, if any.
3. Determine if there is any disadvantage/advantage in terms of the results of the organic compound classification in setting a permanent Lunar research station in this location.
Sources of Error: (include at least three!!!) and give details to how they would affect the experimental results. All of these sources of errors must have been previously documented in the anecdotal observations section. 1.
2.
3.
Extra:
Note: sources of error do not usually include the calibration of the instruments used.
Conclusions: State any conclusions that this experiment has led to.
