Solvent miscibility

Topic LCI-USG-0046, Last Updated 11/08/2024

Before you change solvents, consult this table to determine solvent miscibility.

Be aware of the following effects and considerations:

Temperature affects solvent miscibility. If you are running a high-temperature application, consider the effect of the higher temperature on solvent solubility.
Buffers dissolved in water can precipitate when mixed with organic solvents.
You can make changes involving two miscible solvents directly. Changes involving two solvents that are not totally miscible (for example, from chloroform to water) require an intermediate solvent like n-propanol.
When you switch from a strong buffer to an organic solvent, thoroughly flush the system with distilled water before you add the organic solvent.

Note: λ cutoff is the wavelength at which the absorbance of the solvent equals 1 AU.

Table 1. Solvent miscibility
Solvent	Polarity index	Viscosity cP, 20 °C (at 1 atm)	Boiling point °C (at 1 atm)	Miscibility number (M)	λ cutoff (nm)
ACN	6.2	0.37	81.6	11, 17	190
Acetic acid	6.2	1.26	117.9	14	n/a
Acetone	5.4	0.32	56.3	15, 17	330
Benzyl alcohol	5.5	5.80	205.5	13	n/a
DMF	6.4	0.90	153.0	12	n/a
DMSO	6.5	2.24	189.0	9	n/a
Ethanol	5.2	1.20	78.3	14	210
n-Hexane	0.0	0.313	68.7	29	n/a
MeOH	6.6	0.60	64.7	12	210
Methoxyethanol	5.7	1.72	124.6	13	n/a
1-Propanol	4.3	2.30	97.2	15	210
2-Propanol	4.3	2.35	117.7	15	n/a
THF	4.2	0.55	66.0	17	220
Triethylamine	1.8	0.38	89.5	26	n/a
Water	9.0	1.00	100.0	n/a	n/a

Contents

Using miscibility numbers

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Solvent miscibility