Category: Organic Chemistry

Copyright 2019 Shirley Chung. All rights reserved.

Articles of interest.

Chagrin Valley Soap & Salve Company. (2014, June 16). The Origin and History of Soap. Retrieved from https://www.chagrinvalleysoapandsalve.com/blog/posts/what-is-the-origin-of-soap/

Wallace, T., Gibbons, D., O’Dwyer, M., & Curran, T. P. (2017). International evolution of fat, oil and grease (FOG) waste management–A review. Journal of Environmental Management, 187, 424-435.

Zhang, L., Wang, S., Yang, R., Mao, J., Jiang, J., Wang, X., … & Li, P. (2019). Simultaneous determination of tocopherols, carotenoids and phytosterols in edible vegetable oil by ultrasound-assisted saponification, LLE and LC-MS/MS. Food chemistry, 289, 313-319.

Zhu, X. N., Nie, C. C., Zhang, H., Lyu, X. J., Qiu, J., & Li, L. (2019). Recovery of metals in waste printed circuit boards by flotation technology with soap collector prepared by waste oil through saponification. Waste Management, 89, 21-26.

Carbohydrates have the general formula of Cn H2n On, where the “n” is a number and subscripted. They hydrolyze to a polyhydroxy aldehyde or a polyhydroxy ketone. At the top of the Haworth projection

• Carbohydrates have the general formula of Cn H2n On, where the “n” is a number and subscripted.
• They hydrolyze to a polyhydroxy aldehyde or a polyhydroxy ketone.
• At the top of the Haworth projection, there’s either an aldehyde group for an aldose or a ketone group for an aldose.
• Monosaccharides have 3-6 carbons in the parent chain with a carbonyl group.
• If the carbonyl is at the C1 position, it’s an aldose. If the carbonyl is at the C2 position, it’s a ketose.
• In a Fischer projection, the vertical lines/backbone “recede and go away and into the page like a dashed-wedge” while the horizontal lines “come out like a wedge”.
• If there are n carbons, then look closely at the n-1 carbon position. If the H–OH with the OH on the right side, then the compound is labeled “D”. If the HO–H at the n-1 carbonposition, then the compound is designated “L”.
• A chiral carbon is one where the carbon is attached to four unique bonding groups. A carbon participating in a double or triple bond cannot be a chiral carbon.
• The human body uses “D” sugars.
• To draw the enantiomer, swap the position of “H” and “OH” down the backbone (i.e. just make them reverse of what they currently are).

Fischer to Haworth Projections (straight chain to cyclic form)

For a 6-member ring.

• Turn the Fischer diagram 90 degrees clockwise (lay it on it’s side).
• Substituents below the carbon backbone get the downward position. Substituents above the carbon backbone get the up position.
• Twist carbon-5 so that the OH group is near the carbon-1 putting carbon-6 (CH2OH) sticking up above the ring.
• The -OH group on carbon-5 reacts with the aldehyde group on carbon-1 thereby closing the ring. An oxygen takes the position between carbon-5 and carbon-1.
• The OH-H group on carbon-1 can have the OH in the “up” position (beta form, b like a bird). The OH-H group on carbon-1 can also have the OH in the “down” position (alpha form, Greek A looking like a fish in the sea).
• Carbon-1 is called the anomeric carbon where linkages are possible.

For a 5-member ring.

• A ketone at the second carbon position reacts with the OH at the n-1 carbon position to form a 5-member ring instead of a 6-member ring.

More to be continued. Work in progress.

Now that you have the basics of naming, here are some tips on prioritization rules (i.e. giving functional groups priority or the lowest position number).

• Double bond “-enes” have priority over triple bond “-ynes”.
• Triple bond -ynes get priority over over phenyl.
• Halides/halogens have no special priority over alkyl groups.
• In general, you can expect any functional group containing an oxygen will have priority over functional groups without the oxygen.
• Alcohol has priority over alkyl, amines, halides, ethers, phenyl, and thiols.
• Thiols -SH get priority over alkyl and halides.
• If both thiols and alcohols are present, then alcohol gets priority.
• Aldehyde gets priority over double bond -enes and alcohol.
• Carboxyl group gets priority over aldehydes.
• Ketones get priority over -enes, phenyls, and alcohols.
• Carboxylic acids are highest priority and are terminal; there can only be a maximum of two carboxylic acids. Carboxylic acids get priority over alcohols, amines, ketones and aldehydes.
• Non carboxylic acid carbonyls (acting as substituents) get the “oxo” name.
• Esters have priority over carboxylic acids and the nitrile group.
• Groups with oxygen have priority over amines.
• Amides get priority over amines.

• Identify the longest carbon chain.
• When naming, identify different substituents and functional groups. Keep in mind that at some point, you’ll put these into alpha order unless otherwise noted.
• X, Y, Z-name. Position numbers are separated by commas. The substituent(s) is separated from those position numbers by a dash.
• Ignore di-, tri-, etc. when naming (they don’t “count” when putting substituents/groups into alpha order).
• Double and triple bonds. Find the longest chain that includes as many of these bonds as possible. Give the first carbon of the multiple bond the lower position number. Double bonds “-enes” get priority over triple bonds “-ynes”.
• Alkyl groups have the same level of priority as halogens.
• Double and triple bonds get priority (lower position numbers) over alkyls and halogens.
• Alcohols get priority over: alkenes; alkynes; alkyl; halogens. Prefix “-ol”. If there’s double bonds “-enol”.
• Benzene: ortho (o) is the 1,2 position; meta (m) is the 1,3 position; para (p) is the 1,4 position. Memorize as OMP-benzenes!!
• Ether are R-OR. Alkoxy is the -OR group. Hydroxy is -OH. Methoxy is -OCH3. Ethoxy is -OCH2CH3.
• Thiols are -SH and named like alcohols. Drop the “e” of the parent chain and add -thiol.
• Aldehydes. Change -ane to -anal. They’re at ends of chains so the max you can have on one chain is two. For double bonds use “-enal”.
• Ketones. Change “e” to “one”. The position number of the carbonyl carbon gets to be the lowest number (or highest priority). If an alcohol exists, “hydroxy-“. If NH2 exists, “amine-“.
• Work in progress.

Some helpful resources.

• http://leah4sci.com/naming-organic-compounds-iupac-nomenclature/
• https://iupac.org/

Struggling? Go see Leah4Sci. Here are the links to ace Diels-Alder http://leah4sci.com/tag/diels-alder/

Oh! So you’re like me and you’re cramming to understand the Aldol set of reactions and enols? My secret resource is Leah4Sci (basically anything you need that’s chem, ochem, or MCAT oriented). GO SEE LEAH4SCI.

Here’s a link to the Aldol page http://leah4sci.com/aldol-reaction-shortcut/

Here is a link to Aldol addition/condensation reaction trick https://www.youtube.com/playlist?list=PLaySzQJTCO1mXW0zCC3CbRK6sCYvP9FOy

Here is the link to Leah’s entire playlist relating to enols and aldols https://www.youtube.com/playlist?list=PLaySzQJTCO1mXW0zCC3CbRK6sCYvP9FOy

• Carbonyl group is C=O. Has higher BP than hydrocarbons and ethers, and lower FP than alcohols.
• Ketones have 3 carbons singly bonded to each other. The middle carbon is the carbonyl carbon. That means the other two carbons on either side are the alpha carbons.
• Special carbon designation: the first adjacent carbon attached to the carbonyl carbon is the alpha carbon; the secondmost adjacent carbon is the beta carbon; the third-most is the gamma carbon; the fourth-most is the delta carbon.
• Naming: find the longest chain containing the carbonyl carbon and ketone; the —e is changed to —one. Number the carbonyl carbon with the lowest possible number.
• If the aldehyde or ketone has the hydroxyl and/or amine group then the hydroxyl substituent gets called hydroxy— and the amine group gets called amino—.

Common Species to Know

Propanone (acetone).

• Carbonyl group is C=O. Has higher BP than hydrocarbons and ethers, and lower FP than alcohols.
• Aldehydes have the carbonyl group.
• R—CHO.
• Polar due to the oxygen (very electronegative).
• Can form hydrogen bonds with water, but cannot form intermolecular h-bonds to “itself” (other molecules of self).
• Can’t h-bond to aldehydes and ketones.
• Lower boiling point than alcohols.
• Has stacking potential.
• Naming saturated aldehydes: determine the longest chain containing the carbonyl; —e changes to —al; carbonyl carbon gets lowest number; number and name the rest of the substituents.
• Naming unsaturated aldehydes: the parent name goes from —ane to —enal; carbonyl carbon gets lowest number; and the rest follows the other unsaturated hydrocarbon rules.
• If the aldehyde or ketone has the hydroxyl and/or amine group then the hydroxyl substituent gets called hydroxy— and the amine group gets called amino—.
• Special carbon designation: the first adjacent carbon attached to the carbonyl carbon is the alpha carbon; the secondmost adjacent carbon is the beta carbon; the third-most is the gamma carbon; the fourth-most is the delta carbon.

Common Species to Know

Formaldehyde (methanal). H—CHO. BP -21 degress C. Disinfectant and tissue fixative/preservative agent.

Ethanal (acetaldehyde).

(Work in progress).

Pre-Lab Questions.

• What is the purpose/function of the saturated NaCl (aq)?
• What is the purpose/function of the anhydrous sodium sulfate?
• What is the purpose/function of the dichloromethane?
• In the separatory funnel, which layer is the aqueous layer and which layer is the organic layer?
• What is the density of water vs. dichloromethane?

Materials and Methods. Clove oil was extracted from ground cloves in three major processes: steam distillation; crude oil extraction; and product purification.

Steam distillation. Ground cloves were boiled in closed, horizontal, simple steam distillation setup (round-bottom boiling flask, Claisen tube, distilling head, water condenser, vacuum adapter, small separatory funnel to renew the water supply, and receiving flask) which yielded 30 mL of distillate.

Crude oil extraction. The distillate was transferred to a separatory funnel. Saturated NaCl solution was added to the distillate to “pull” the aqueous layer out as a diluent for the NaCl (aq). To further separate the aqueous and organic layers, the distillate was washed with a small amount of dichloromethane and then shaken vigorously (venting frequently). Upon settling, the denser organic layer was drained from the separatory funnel into an Erlenmeyer flask. This process was repeated 3 times. This crude extraction was based on the principle: “like dissolves like” or “like is miscible in like”.

Oil purification. Anhydrous Na₂SO₄ was added to the crude oil (repeated if necessary) to absorb any remaining water. When the mixture looked “granular” or turbid, the dried dichloromethane/organic solution was transferred to a pre-weighed boiling flask (boiling chip inside). A rotary evaporator removed the rest of the dichloromethane leaving a purified clove oil product.

Resources:

• https://orgchemboulder.com/Technique/Procedures/Drying/Drying.shtml
• http://employees.oneonta.edu/knauerbr/chem226/226expts/226_expt06_pro.pdf

• Ethers have the structure R1-O-R2. Memory trick: ethers are eithers, R1 or R2 (a play on either/or).
• Are only slightly polar due to the electronegative oxygen (unless there are other functional groups attached).
• Naming. Ethers have the —oxy suffix. The smaller substituent is the “alkoxy” part. The parent chain is the longer chain (used for the base name). For other hydrocarbon groups, change —yl to —oxy. Then, number the position of the alkoxy.
• —OH, hydroxy
• —OCH(3), methoxy (parenthesis are subscripts)
• —OCH(2)CH(3), ethoxy