ORG-08

E2 rate

r = k [RX][B]. Bimolecular elimination.

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MechanismsIngold E2

Governing equation

r=k[RX][B]

$[B] \in \left[0.001, 2\right]$

where

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

The figure, part by part

Each numbered marker wears the color of its card. Hover a card to light the marker. Tap a marker to jump to that card. The slider walks a red point along the curve; Animate drawing traces it like a pen.

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①

Governing law — red

r=k[RX][B]

$[B] \in \left[0.001, 2\right]$

$[B] = 0.001$ $r = 3\times 10^{-6}$

Along the curve

②

Domain of the variable — blue

[B]_{\min} = 0.001,\quad [B]_{\max} = 2

$[B] \in \left[0.001, 2\right]$

$[B] = 0.001$ $[B] = 0.001$

Along the curve

③

Response curve — green

r=k[RX][B]

$[B] \in \left[0.001, 2\right]$

$[B] = 0.001$ $r = 3\times 10^{-6}$

Along the curve

④

Rate of change — amber

\frac{\mathrm{d}r}{\mathrm{d}[B]}

$[B] \in \left[0.001, 2\right]$

$[B] = 0.014$ $r^{\prime} = 0.003$

Along the curve

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-08 — E2 rate) is the form associated with Ingold E2. Working symbols: $k$ , $[RX]$ , $[B]$ $\rightarrow$ $r$ . Antiperiplanar H and leaving group. Strong base, often competes with SN2.

Purpose

Purpose: compute

r

from

k

[RX]

[B]

in Organic chemistry via

r=k[RX][B]

r = k [RX][B]. Bimolecular elimination. 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 = 0.030\,\mathrm{L/(mol·s)}

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

[B] = 0.250\,\mathrm{mol/L}

, the governing relation

r=k[RX][B]

yields

r = 7.500e-4\,\mathrm{mol/(L·s)}

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

Calculator

Inputs

Rate constant k0.03 L/(mol·s)Substrate [RX]0.1 mol/LBase [B]0.25 mol/L

Outputs

Rate r0.00075 mol/(L·s)

Reading speed

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Narration of this film

Second-order, irreversible.

Antiperiplanar H and leaving group. Strong base, often competes with SN2.

Reading speed

Watch on YouTube