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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.

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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 ↗

Anchor reagent — fix this amount, scale everything else Substrate concentration · M

Amount r Unit

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Reactants

Reactants for Henry reaction (nitroaldol addition): stoichiometric quantities derived from the anchor amount.
Reagent	Equiv	Moles · mmol	Mass · g	Volume · mL
Nitromethane SDS 75-52-5 · CH3NO2	1.0	100.00	6.104	5.40
Benzaldehyde 100-52-7 · C7H6O	1.0	100.00	10.612	10.11

Catalyst

Catalyst for Henry reaction (nitroaldol addition): stoichiometric quantities derived from the anchor amount.
Reagent	Equiv	Moles · mmol	Mass · g	Volume · mL
109-73-9 109-73-9 · C4H11N	0.1	10.00	0.731	1.00

Solvent

Solvent for Henry reaction (nitroaldol addition): stoichiometric quantities derived from the anchor amount.
Reagent	Equiv	Moles · mmol	Mass · g	Volume · mL
Acetic Acid 64-19-7 · C2H4O2	—	3463.78	208.000	200.00

Product

Product for Henry reaction (nitroaldol addition): stoichiometric quantities derived from the anchor amount.
Reagent	Equiv	Moles · mmol	Mass · g	Volume · mL
Β-Nitrostyrene 102-96-5 · C8H7NO2 density unavailable — volume not calculable.	1.0	100.00	14.915	—

Expected isolated yield

What you should actually weigh out of the recrystallisation flask, scaled from the limiting reactant via the canonical-procedure yield window.

Product: Β-Nitrostyrene 102-96-5 · C8H7NO2
Theoretical max: 14.91 g (100.00 mmol)
Expected isolated · 70–80 % yield: 10.44 – 11.93 g

Stoichiometry: moles_X = (moles_anchor / equiv_anchor) × equiv_X. Mass = moles × MW; volume = mass / ρ. Solvent volume = total reactant moles ÷ substrate concentration.