Lauric acid
Chemical compound
From Wikipedia, the free encyclopedia
Lauric acid, systematically dodecanoic acid, is a saturated fatty acid with a 12-carbon atom chain, thus having many properties of medium-chain fatty acids.[6] It is a bright white, powdery solid with a faint odor of bay oil or soap. The salts and esters of lauric acid are known as laurates. Lauric acid accounts for nearly half of the fat in coconut oil and palm kernel oil.
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| Names | |
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| Preferred IUPAC name
Dodecanoic acid | |
| Other names
n-Dodecanoic acid, Dodecylic acid, Dodecoic acid,
Laurostearic acid, Vulvic acid, 1-Undecanecarboxylic acid, Duodecylic acid, C12:0 (Lipid numbers) | |
| Identifiers | |
3D model (JSmol) |
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| ChEBI | |
| ChEMBL | |
| ChemSpider | |
| ECHA InfoCard | 100.005.075 |
| EC Number |
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| KEGG | |
PubChem CID |
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| UNII | |
CompTox Dashboard (EPA) |
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| Properties | |
| C12H24O2 | |
| Molar mass | 200.322 g·mol−1 |
| Appearance | White powder |
| Odor | Slight odor of bay oil |
| Density | 1.007 g/cm3 (24 °C)[1] 0.8744 g/cm3 (41.5 °C)[2] 0.8679 g/cm3 (50 °C)[3] |
| Melting point | 43.8 °C (110.8 °F; 316.9 K)[3] |
| Boiling point | 297.9 °C (568.2 °F; 571.0 K) 282.5 °C (540.5 °F; 555.6 K) at 512 mmHg[1] 225.1 °C (437.2 °F; 498.2 K) at 100 mmHg[3][4] |
| 37 mg/L (0 °C) 55 mg/L (20 °C) 63 mg/L (30 °C) 72 mg/L (45 °C) 83 mg/L (100 °C)[5] | |
| Solubility | Soluble in alcohols, diethyl ether, phenyls, haloalkanes, acetates[5] |
| Solubility in methanol | 12.7 g/100 g (0 °C) 120 g/100 g (20 °C) 2250 g/100 g (40 °C)[5] |
| Solubility in acetone | 8.95 g/100 g (0 °C) 60.5 g/100 g (20 °C) 1590 g/100 g (40 °C)[5] |
| Solubility in ethyl acetate | 9.4 g/100 g (0 °C) 52 g/100 g (20°C) 1250 g/100 g (40°C)[5] |
| Solubility in toluene | 15.3 g/100 g (0 °C) 97 g/100 g (20°C) 1410 g/100 g (40°C)[5] |
| log P | 4.6[6] |
| Vapor pressure | 2.13·10−6 kPa (25 °C)[6] 0.42 kPa (150 °C)[4] 6.67 kPa (210 °C)[7] |
| Acidity (pKa) | 5.3 (20 °C)[6] |
| Thermal conductivity | 0.442 W/m·K (solid)[2] 0.1921 W/m·K (72.5 °C) 0.1748 W/m·K (106 °C)[1] |
Refractive index (nD) |
1.423 (70 °C)[1] 1.4183 (82 °C)[3] |
| Viscosity | 6.88 cP (50 °C) 5.37 cP (60 °C)[2] |
| Structure | |
| Monoclinic (α-form)[8] Triclinic, aP228 (γ-form)[9] | |
| P21/a, No. 14 (α-form)[8] P1, No. 2 (γ-form)[9] | |
| 2/m (α-form)[8] 1 (γ-form)[9] | |
α = 90°, β = 129.22°, γ = 90° | |
| Thermochemistry | |
Heat capacity (C) |
404.28 J/mol·K[4] |
Std enthalpy of formation (ΔfH⦵298) |
−775.6 kJ/mol[6] |
Std enthalpy of combustion (ΔcH⦵298) |
7377 kJ/mol 7425.8 kJ/mol (292 K)[4] |
| Hazards | |
| GHS labelling: | |
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| Danger | |
| H318[7] | |
| P280, P305+P351+P338[7] | |
| NFPA 704 (fire diamond) | |
| Flash point | > 113 °C (235 °F; 386 K)[7] |
| Related compounds | |
Related compounds |
Glyceryl laurate |
| Related compounds | |
Related compounds |
Undecanoic acid Tridecanoic acid Dodecanol Dodecanal Sodium lauryl sulfate |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Occurrence
Lauric acid, as a component of triglycerides, comprises about half of the fatty-acid content in coconut milk, coconut oil, laurel oil, and palm kernel oil (not to be confused with palm oil).[10][11][12] Oils with high levels of lauric acid are known as lauric oils.[13][14] Otherwise, it is relatively uncommon. It is also found in human breast milk (6.2% of total fat), cow's milk (2.9%), and goat's milk (3.1%).[10]
In various plants
- The palm tree Attalea speciosa, a species known in Brazil as babassu – 50% in babassu oil
- Attalea cohune, the cohune palm (also rain tree, American oil palm, corozo palm or manaca palm) – 46.5% in cohune oil
- Astrocaryum murumuru (Arecaceae) a palm native to the Amazon – 47.5% in "murumuru butter"
- Coconut oil 47-49%
- Pycnanthus kombo (African nutmeg)
- Virola surinamensis (wild nutmeg) 7.8–11.5%
- Peach palm seed 10.4%
- Betel nut 9%
- Date palm seed 0.56–5.4%
- Macadamia nut 0.072–1.1%
- Plum 0.35–0.38%
- Watermelon seed 0.33%
- Viburnum opulus 0.24-0.33%[15]
- Citrullus lanatus (egusi melon)
- Pumpkin flower 205 ppm, pumpkin seed 472 ppm
Insect
- Black soldier fly Hermetia illucens 30–50 mg/100 mg fat.[16]
Uses
Like many other fatty acids, lauric acid is inexpensive, has a long shelf-life, is nontoxic, and is safe to handle. It is used mainly for the production of soaps and cosmetics. For these purposes, lauric acid is reacted with sodium hydroxide to give sodium laurate, which is a soap. Most commonly, sodium laurate is obtained by saponification of various oils, such as coconut oil. These precursors give mixtures of sodium laurate and other soaps.[11]
Lauric acid is a precursor to dilauroyl peroxide, a commercial initiator of polymerizations.[6]
Production and reactions
Lauric acid is mainly isolated from natural sources.[11] Its reactions are representative of those of similar long chain, saturated fatty acids. It can be converted to the symmetrical fatty ketone called laurone (O=C(C11H23)2).[17] It transesterifies with vinyl acetate.[18] Treatment with sulfur trioxide gives the α-sulfonic acid.[19]
As a dietary fat and cardiovascular risk factor
Lauric acid increases total serum lipoproteins more than many other fatty acids, including LDL and high-density lipoprotein (HDL), making it a risk factor for cardiovascular diseases.[12] Lauric acid has been characterized as having "a more favorable effect on total HDL than any other fatty acid [examined], either saturated or unsaturated",[20] which may favor a lower cardiovascular disease risk.[21] However, given the prominence of lauric acid in palm kernel and coconut oil (about 47% of total fat), replacing dietary coconut oil and its high lauric acid content with oils containing mostly unsaturated fats would alter total blood lipids in a way that reduces cardiovascular disease risk.[12]
Although 95% of medium-chain triglycerides are absorbed through the portal vein, only 25–30% of lauric acid is absorbed through this vein.[12][22]
