ORG-07

SN2 rate

r = k [RX][Nu]. Bimolecular nucleophilic substitution.

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MechanismsIngold SN2

Governing equation

r=k[RX][Nu]

where

k: Rate constant (L/(mol·s))
[RX]: Substrate (mol/L)
[Nu]: Nucleophile (mol/L)
r: Rate (mol/(L·s))

Lecture brief

Historical brief

Hammett (1937) and Taft linear free-energy, E-factor green metrics, Woodward–Fieser UV and Claisen equilibria are how organic chemistry became predictive. The lab is substituent, waste and tautomer. This sheet (ORG-07 — SN2 rate) is the form associated with Ingold SN2. Working symbols: $k$ , $[RX]$ , $[Nu]$ $\rightarrow$ $r$ . Concerted backside attack. Primary substrates, polar aprotic solvents, good nucleophiles.

Purpose

Purpose: compute

r

from

k

[RX]

[Nu]

in Organic chemistry via

r=k[RX][Nu]

r = k [RX][Nu]. Bimolecular nucleophilic substitution. Use it when a real organic chemistry question must be answered in SI before a code check.

Live realistic example

In symbols

Live case. Given

k = 0.050\,\mathrm{L/(mol·s)}

[RX] = 0.100\,\mathrm{mol/L}

[Nu] = 0.200\,\mathrm{mol/L}

, the governing relation

r=k[RX][Nu]

yields

r = 0.00100\,\mathrm{mol/(L·s)}

. Second-order, irreversible. Move a slider: the numbers are this situation, not a canned story.

Calculator

Inputs

Rate constant k0.05 L/(mol·s)Substrate [RX]0.1 mol/LNucleophile [Nu]0.2 mol/L

Outputs

Rate r0.00100 mol/(L·s)

Reading speed

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Narration of this film

Second-order, irreversible.

Concerted backside attack. Primary substrates, polar aprotic solvents, good nucleophiles.

Reading speed

Watch on YouTube