Table 1.
Information on acid and alkali agents tested.
| Chemical | IUPAC Name | CAS No. | Molecular Weight |
Molecular Formula |
Purity | Water Solubility b |
pH (Skin Irritation a) | ECHAb | ||
|---|---|---|---|---|---|---|---|---|---|---|
| 0.1 M | 1.0 M | Skin hazard |
Source | |||||||
| Organic acid | ||||||||||
| Citric acid | 2-Hydroxypropane-1,2,3-tricarboxylic acid | 77-92-9 | 192.12 | C6H8O7 | ≥97% | 540 g/L | 1.89 (NI) | 1.13 (I) | Mildly irritating (0.5 g powder) |
[15] |
| Glycolic acid | 2-Hydroxyacetic acid | 79-14-1 | 76.05 | C2H4O3 | 99% | > 300 g/L | 2.41 (NI) | 1.61 (I) | Skin Corr. 1B (99% liquid) |
[16] |
| Lactic acid | 2-Hydroxypropanoic acid | 50-21-5 | 90.08 | C3H6O3 | 88–92% | 861 g/L | 2.43 (NI) | 1.60 (NI) | Mildly irritating (88% aqueous solution) |
[17] |
| Malic acid | 2-Hydroxybutanedioic acid | 6915-15-7 | 134.09 | C4H6O5 | ≥99% | 647 g/L | 2.25 (NI) | 1.43 (I) | Mildly irritating (0.5 g wetted with paraffin oil) |
[18] |
| Succinic acid | Butanedioic acid | 110-15-6 | 118.09 | C4H6O4 | ≥99% | 83 g/L | 2.60 (NI) | 1.82 (I) | Not irritating (0.5 g moistened with water) |
[19] |
| Inorganic acid | ||||||||||
| Hydrogen bromide | Bromane | 10035-10-6 | 80.91 | HBr | 30–32% in acetic acid |
665 g/L | 0.55 (NI) | −0.66 (I) | Skin Corr. 1A | [20] |
| Hydrogen chloride | Chlorane | 7647-01-0 | 36.46 | HCl | 37% aq. solution |
500 g/L | 0.69 (NI) | −0.29 (I) | Skin Corr. 1A (25~30%) |
[21] |
| Nitric acid | Nitric acid | 7697-37-2 | 63.01 | HNO3 | 70% aq. solution |
>500 g/L | 0.58 (NI) | −0.39 (I) | Skin Corr. 1A (≥28%) |
[22] |
| Sulfuric acid | Sulfuric acid | 7664-93-9 | 98.08 | H2SO4 | 95–98% | 1000 g/L | 0.47 (NI) | −0.55 (I) | Skin Corr. 1A (Predicted) |
[23] |
| Organic alkali | ||||||||||
| Ethanolamine | 2-Aminoethanol | 141-43-5 | 61.08 | C2H7NO | ≥99% | 1000 g/L | 11.40 (NI) | 12.00 (I) | Skin Corr. 1B (Neat liquid, 20% solution) |
[24] |
| Triethanolamine | 2-[Bis(2-hydroxyethyl)amino]ethanol | 102-71-6 | 149.19 | C6H15NO3 | ≥99% | 1000 g/L | 10.36 (NI) | 10.90 (NI) | Not irritating (0.5 mL neat) |
[25] |
| Inorganic alkali | ||||||||||
| Sodium hydroxide | Sodium hydroxide | 1310-73-2 | 39.997 | HNaO | ≥97% | 1000 g/L | 13.07 (NI) | 13.68 (I) | Skin Corr. 1A (>2%) |
[26] |
| Sodium carbonate | Disodium carbonate | 497-19-8 | 105.988 | Na2CO3 | ≥99.5% | 212.5 g/L | 11.49 (NI) | 11.60 (NI) | Not irritating (0.5 g) |
[27] |
a NI; Non-irritant, I; irritant. b ECHA database accessed through eChemportal on 19 September 2022 [15].