Isopropyl alcohol

February 12, 2024
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Isopropyl alcohol (IPA; aka 2-propanol, but never “isopropanol”) is a common solvent, reagent, and disinfectant. It is flammable, with a characteristic odor that is similar to ethanol’s, but more pungent.

IPA dates to 1866 in the chemical literature, when it was mentioned by Eduard Linnemann at the University of Lemberg (Poland)1 in an article about the conversion of propylene oxides to acetone. As described by Carleton Ellis in a 1921 article in Petroleum Magazine, IPA was first produced commercially by Standard Oil in 1920 from paraffin oil–derived propylene via its reaction with sulfuric acid, followed by hydrolysis. Much of the alcohol was then oxidized to acetone.

According to the Merck Index, IPA has a wide range of uses: in antifreeze compositions; as an industrial solvent for gums, resins, and creosote; in quick-drying inks and oils; in cosmetic products such as body rubs, hand lotions, and after-shave formulations; and in the manufacture of acetone, glycerol, and isopropyl acetate. It also has several medical uses, including in rubbing alcohol, hand sanitizers, and “wet wipes”.

In 2022, the global market for IPA was ≈2.3 million tonnes. It is forecast that the volume will grow to ≈2.9 million tonnes by 2030.

1. Now the University of Lviv (Ukraine).

Isopropyl alcohol hazard information

Hazard class*GHS code and hazard statement
Flammable liquids, category 2H225—Highly flammable liquid and vaporChemical Safety Warning
Serious eye damage/eye irritation, category 2AH319—Causes serious eye irritationChemical Safety Warning

Specific target organ toxicity, single exposure, respiratory tract irritation, category 3

H335—May cause respiratory irritationChemical Safety Warning

Specific target organ toxicity, single exposure, narcotic effects, category 3

H336—May cause drowsiness or dizzinessChemical Safety Warning
Specific target organ toxicity, repeated exposure (kidney, liver), category 2H373—Causes damage to organs through prolonged or repeated exposureChemical Safety Warning

*Globally Harmonized System (GHS) of Classification and Labeling of Chemicals. Explanation of pictograms.

Molecules from the journals

Indium zinc sulfide (In2Zn3S6)1 is a crystalline inorganic compound that was prepared in single-crystal sheets by USSR scientists V. F. Zhitar*, N. A. Goryunova, and S. I. Radautsan* in 1965. The authors described In2Zn3S6 as having photoelectric properties.

This January, Xue-Fang Yu, Kaisheng Zhang, Xiaolong Yang, and collaborators at Qingdao University, Yantai University, and the Chinese Academy of Sciences (Hefei, all in China) reported that In2Zn3S6, with sulfur vacancies, is an ideal photothermal catalyst for promoting the cycloaddition of carbon dioxide to epoxides (e.g., propylene oxide2) to form cyclic carbonates. The authors propose that this reaction system could contribute to CO2 capture and the synthesis of useful materials.

Dihydro-β-ionone3 is a cyclic unsaturated ketone first reported in 1934 by Leopold Ružička4* and W. Fischer at ETH Zurich in the 90th (!) article of a series on polyterpenes and polyterpenoids. The article concentrated primarily on the synthesis of 1-β-cyclogeranylgeraniol[MB1] ; but the authors also prepared dihydro-β-ionone via the partial catalytic hydrogenation of β-ionone5.

Dihydro-β-ionone is one of several ionones (also known as “rose ketones”) that are components of flavor and fragrance products. In January, Su Bu, Longuo Zhao, and co-workers at Nanjing Forest University (China) described a biochemical synthesis of the molecule from glycerol6. They used an Escherichia coliSaccharomyces cerevisiae coculture to produce dihydro-β-ionone with a titer of 27 mg/L, considerably higher than the 8 mg/L obtained with E. coli alone.

1. CAS Reg. No. 12056-06-3.
2. CAS Reg. No. 75-56-9.
3. CAS Reg. No. 17283-81-7.
4. Ružička was a co- winner of the 1939 Nobel Prize in Chemistry for his work on polyethylene and terpenes.
5. CAS Reg. No. 79-77-6.
6. CAS Reg. No. 56-81-5.

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Isopropyl alcohol fast facts

CAS Reg. No.67-63-0
SciFinder nomenclature2-Propanol
Empirical formulaC3H8O3
Molar mass60.10 g/mol
AppearanceColorless liquid
Boiling point82.5 °C
Water solubilityMiscible
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