Skip to results

Tools · Synthesis

Reaction Scale Calculator

Pick a stored reaction, fix one reagent's amount, get every other reagent's quantity by stoichiometric equivalents. Solvent volume derived from your substrate concentration. Densities + molar masses come from our molecule database.

Press / to jump here from anywhere. Type to filter.

Henry reaction (nitroaldol addition)

RCH₂NO₂ + R'CHO → R'CH(OH)CH(NO₂)R

Base-catalysed addition of a nitroalkane to an aldehyde to give a β-nitro alcohol that dehydrates under Knoevenagel-Henry conditions to the conjugated nitroalkene. Default example here is the textbook β-nitrostyrene prep — yellow needles, mp 58 °C, recrystallised from EtOH.

Conditions: Knoevenagel-Henry variant: glacial acetic acid (or 80 % aq. AcOH for milder conditions) with n-butylamine (5–20 mol%). Run at 20–25 °C in the dark for the slow variant, or at reflux (~118 °C glacial) for the faster Knoevenagel variant. Workup: pour onto cold water, filter the yellow nitrostyrene, recrystallise from boiling EtOH. Slow cooling gives larger needles; seeding the cooling solution with a previously-isolated crystal accelerates onset. Classical alternative (Worrall, Org. Synth. Coll. Vol. 1, 413): NaOH in MeOH at 0–5 °C — fast (≤1 h to first crop) but lower yield (~50 %).

Expected yield
70–80 %
Expected duration
5–14 days at RT in the dark; 3–6 h at reflux (Knoevenagel variant)

Mechanism reference ↗

Scale inputs

Anchor reagent + concentration

Total reactant moles divided by this concentration sets the solvent volume.

Anchor amount

Updates as you type · the URL captures every input.

Computed quantities

Keyboard shortcuts

/
Focus the reaction picker
r
Focus the Amount input
c
Copy the procedure to clipboard
p
Print this procedure
u
Copy share URL to clipboard
d
Download reagent table as CSV
/ Ctrl +
Force a recompute
?
Show this help
Esc
Close this dialog

Single-key shortcuts only fire when no input has focus. The URL bar captures every input, so the calculation is always shareable.

Recent Searches

Acetone
Ethanol
Navigate
esc Close