13 Carboxylic Acids

A great many of carboxylic acids are found in nature.For example, acetic acid is the chief organic component of vinegar;butanoic acid is responsible for the odor of sour butter;Hexanoic acid (capoic acid ) is responsible for the unmistakable aroma of goats and dirty gym socks.

Cholic acidCholic acid is a major component of human bile.

Cholic acid

13.1 1 152pm131pm125pm119119122

2 2.1 IUPACIUPAC rules allow for two systems of nomenclature, depending on the complexity of the acid molecule.Carboxylic acids that are derived from openchainalkanes are systematically named by replaceing the terminal-e of the correspoding alkane name with oic acid. The carboxyl carbon atom is numdered C1 in this system.4-2E,4E-2,4-++

Alternatively, compounds that have a COOH group Bonded to a ring are named using the carbooxylic acid.The COOH carbon is attached to C1 and is not itself Numbered in this system.3-1-

-1,3-2-1-4-

2 Because many carboxylic acids were among the first organic compounds to be isolated and purified, a large number of common names are recognized by IUPAC, some of which are given below. HCOOH CH3COOH CH3CH2COOH CH3CH2CH2COOH CH3(CH2)16COOH

HOOCCOOH HOOCCH2COOH HOOC(CH2)2COOH (Z)-HOOCCH=CHCOOH (E)-HOOCCH=CHCOOH

3 3.1 R

3.2 PH

13.2 (C4; ; 1. 2. Acetic acid dimer46100.7 78.3

3. 1HNMRR2CHCOOH H 10~12 HCR2COOH H 2~2.6IRC=O RCOOH 1770~1750cm-1 ~1710cm-1CH2=CHCOOH ~ 1720 cm-1 ~1690cm-1ArCOOH 1700-1690cm-1OH ~ 3550 cm-1 3000 ~2500cm-1C-O ~ 1250 cm-1 IROH 3000cm-1

OH

1H NMR spectrum (CDCl3, 500 MHz)

13C NMR spectrum (CDCl3, 125 MHz)

positive EI Mass Spectrum

13.3

Since a carboxylate ion is more stable than an alkoxide ion, it is lower in energy and more highly favored at eqilibrium, as shown in the reaction energy diagram below.

1

2

3

1 2 H+H+.

3

> > > >

pKa 2.98 pKa 4.07 pKa 4.48 pKa 4.19

13.4 OH 1 -----OH bp 70.4 *

PolyestersThe most generally useful polyester is that made by reaction between dimethyl terephthalate ethylene glycol. The product is used under the trade name Dacron to make clothing fiber and tire cord, and under the nameMylar to make recording tape. The tensible strength of poly(ethylene Terephthalate) film is nearly equal to that of steel.

100%

2 N-

DIBAH

66Wallace Hume Carothes nHO2C(CH2)4COOH + nH2N(CH2)6NH2270oC 1MPa+ nH2ONylon66Nylons are used both in engineering applications and in making fibers. A combination of high strength and abrasion resistance makes nylon an excellent metal substitute for bearings and gears. As fiber,nylon is used in a wide variety of applications, from clothing to tire cord to Perlon mountaineering ropes.

Wallace Hume Carothers(1896-1937) was born in Burlington, Iowa, and received his Ph.D. at the University of illinois in 1924 with Roger Adams. He began his career with brief teaching positions at the University of South Dakota , the university of Illinois, and Harvard Universuty , but moved to the Du Pont Company in 1928 to head their new chemsitry research program in Polymers. A prolonged struggle with depression led him to suicide after only 9 years at Du Pont.

Wallace Hume Carothers (b. April 27, 1896, d. April 29, 1937) can be considered the father of the science of man-made polymers and the man responsible for the invention of nylon and neoprene. The man was a brilliant chemist, inventor and scholar and a troubled soul. Despite an amazing career, Wallace Carothers held more than fifty patents; the inventor ended his own life. Wallace Carothers was born in Iowa and first studied accounting and later studied science (while teaching accounting) at Tarkio College in Missouri. While still an undergraduate student, Wallace Carothers became the head of the chemistry department. Wallace Carothers was talented in chemistry but the real reason for the appointment was a personnel shortage due to the war effort (WWI). He received both a Master's degree and PhD from the University of Illinois and then became a professor at Harvard, where he started his research into chemical structures of polymers in 1924.

In 1928, the DuPont chemical company opened a research laboratory for the development of artificial materials, deciding that basic research was the way to go -- not a common path for a company to follow at the time. Wallace Carothers left Harvard to lead Dupont's research division. A basic lack of knowledge of polymer molecules existed when Wallace Carothers began his work there. Wallace Carothers and his team were the first to investigate the acetylene family of chemicals. In 1931, DuPont started to manufacture neoprene, a synthetic rubber created by Carothers' lab. The research team then turned their efforts towards a synthetic fiber that could replace silk. Japan was the United States' main source of silk, and trade relations between the two countries were breaking apart. By 1934, Wallace Carothers had made significant steps toward creating a synthetic silk by combining the chemicals amine, hexamethylene diamine and adipic acid to create a new fiber formed by the polymerizing process and known as a condensation reaction. In a condensation reaction, individual molecules join with water as a byproduct. Wallace Carothers refined the process (since the water produced by the reaction was dripping back into the mixture and weakening the fibers) by adjusting the equipment so that the water was distilled and removed from the process making for stronger fibers. DuPont patented the new fiber as "nylon" the following year.

Polymers are any of a class of natural or synthetic substances composed of very large molecules called macromolecules that are multiples of simpler chemical units called monomers. Polymers make up many of the materials in living organisms, including, for example, proteins, cellulose, nucleic acids, natural rubber and silk. Those synthesized in the laboratory have led to such commercially important products as plastics, synthetic fibers and synthetic rubber. See also: Polymers a brief description Acetylene is a colorless gas and the simplest and best-known member of the hydrocarbon series (molecules containing one or more pairs of carbon atoms linked by triple bonds), called the acetylenic series or alkynes. Explosive on contact with air, it is stored dissolved under pressure in acetone and used to make neoprene rubber, plastics, and resins. In metal welding, the oxyacetylene torch mixes and burns oxygen and acetylene to produce a very hot flame (as high as 6300F).

Nylon, a synthetic thermoplastic material introduced in 1938, is a strong elastic, resistant to abrasion and chemicals and low in moisture absorbency. Extract from "Fortune Magazine" about nylon circa 1938: "nylon breaks the basic elements like nitrogen and carbon out of coal, air and water to create a completely new molecular structure of its own. It flouts Solomon. It is an entirely new arrangement of matter under the sun, and the first completely new synthetic fiber made by man. In over four thousand years, textiles have seen only three basic developments aside from mechanical mass production: mercerized cotton, synthetic dyes and rayon. Nylon is a fourth."

In 1936, Wallace Carothers married Helen Sweetman, a fellow employee at DuPont. They had a daughter, but tragically Wallace Carothers committed suicide before the birth of this first child. It was likely that Wallace Carothers was a severe manic-depressive, and the untimely death of his sister in 1937 added to his depression. A fellow Dupont researcher, Julian Hill, had once observed Carothers carrying what turned out to be a ration of the poison cyanide. Hill remarked that Carothers could list all the famous chemists who had committed suicide. In April of 1937, Wallace Hume Carothers consumed that ration of poison himself and added his own name to that list. Nylon, the miracle fiber, was introduced to the world in 1938.

3 *

4 *

13.51 -C

(Kolbe)(Hunsdicker)(Cristol S) (Kochi) 2CH3COONaC2H6 + CO2 + NaOH + H22H2ORCH2COOHRCH2COOAgRCH2BrAgNO3 KOHBr2 CCl4RCH2COOHRCH2COOHgRCH2BrHgOBr2 CCl4RCOOHRCOOPb(OAc)3Pb(OAc)4 I2LiCl C6H6RClRCOOHRIPb(OAc)4 I2 Cl4 10C1oRX2oRX,3oRX1oRX1o2o3oRX

Hunsdicker

--CO2

Cl3CCOOH-H+H2OCl3C- + CO2+H+Cl3CH,pka=6.6)

HOOC(CH2)4COOHCH3OOC(CH2)4COOAgBr2 CCl4CH3OOC(CH2)4Br CH3OH H+AgNO3 KOH

. . LiAlH4.

(1) LiAlH4RCOOH + LiAlH4RCOOLi + H2 + AlH3-LiOAlH2R-CH=OAlH3RCH2OAlH2RCH2OHH2O2

2

RCOOH + BH3 -BH2(OH)RCHO BH3RCH2OBH2H2ORCH2OH-COOH > C=O > -CN > -COOR > -COCl

LiAlH4C=C, B2H6C=C LiAlH4CH2=CH-CH2-COOHCH2=CH-CH2-CH2OHCH2=CH-CH2-COOHCH3CH2CH2CH2OHB2H6H2OH2OLiAlH4

3 -H--(Hell-Vihard- Zelinsky)

-H10%~30% -KI2 RCH2COOHPBr3+ Br --HBrRCH2COOH

3 -H

P -H10%~30%

-KI -

13.5 1 62 8 3 10 4 12 5 6

7 Grinard (RLi ) 1oRX2oRX3oRX ArIArBrArCl RLiGrinard RX

LDA/THF-78oCCH3(CH2)3BrH2OCO2-78oCH2O

13.6 1 1 -

(2)

2 pKa1 pKa 2 pKa2

3 Ag2OP2O5Ba(OH)2Ca(OH)2 ~160 ~300 ~300}Blancs Rule

----

13.7 1

2 2.1

2.2

-

3 3.1 2- 2-

3.1 3- -3-

13 1 badcepKa1.7;1.8;2.4;3.6;4.76Propose a synthesis of the anti- inflammatory drug Fenclorac from phenylcyclohexane.

3 Predict the product of thereaction of p-methylbenzoic acid with each of the following:

4 How would you carry out the following transformations?

5 How would you carry out the following reactions?

1H2H2H3H

Methacrylic acidThe other is crotonic acid

12 2010/05/191 ketones reaction with dimethylsulfonium methylide to yield epoxides. Suggest a mechanism for the reaction.dimethylsulfonium methylide

2 Tamoxifen is a drug used in the treatment of breast of cancer. How would you prepqre tamoxifen from

benzene, the following ketone, and any other reagents needed?Tamoxifen(,)

C9H10O 2H3H5H3 The HNMR spectrum show is that of a compoud with formula C9H10O. What is a likely structure?

16832879C9H10O

4 AC12H20, 1molBCC12H22AD C6H10O DDEC6H11NODDClD2OC6H7D3ODHNMR3HAE