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Index/Organic chemistry/ORG-06

ORG-06

SN1 rate

r = k [RX]. Unimolecular nucleophilic substitution.

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MechanismsIngold SN1

Governing equation

r=k[RX]r=k[RX]

[RX]∈[0.001,2][RX] \in \left[0.001, 2\right]

where

k
Rate constant (1/s)
[RX]
Substrate (mol/L)
r
Rate (mol/(L·s))

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ORG-06 · reactor
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①

Governing law — red

r=k[RX]r=k[RX]

[RX]∈[0.001,2][RX] \in \left[0.001, 2\right]

[RX]=0.001[RX] = 0.001r=2×10−6r = 2\times 10^{-6}

②

Domain of the variable — blue

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

[RX]∈[0.001,2][RX] \in \left[0.001, 2\right]

[RX]=0.001[RX] = 0.001[RX]=0.001[RX] = 0.001

③

Response curve — green

r=k[RX]r=k[RX]

[RX]∈[0.001,2][RX] \in \left[0.001, 2\right]

[RX]=0.001[RX] = 0.001r=2×10−6r = 2\times 10^{-6}

④

Rate of change — amber

drd[RX]\frac{\mathrm{d}r}{\mathrm{d}[RX]}

[RX]∈[0.001,2][RX] \in \left[0.001, 2\right]

[RX]=0.014[RX] = 0.014r′=0.002r^{\prime} = 0.002

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-06 — SN1 rate) is the form associated with Ingold SN1. Working symbols: kk, [RX][RX] →\rightarrow rr. Rate-determining ionisation to a carbocation. Tertiary and resonance-stabilised RX.

Purpose

Purpose: compute rr from kk, [RX][RX] in Organic chemistry via r=k[RX]r=k[RX] r = k [RX]. Unimolecular 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=0.002 1/sk = 0.002\,\mathrm{1/s}, [RX]=0.100 mol/L[RX] = 0.100\,\mathrm{mol/L}, the governing relation r=k[RX]r=k[RX] yields r=2.000e−4 mol/(L⋅s)r = 2.000e-4\,\mathrm{mol/(L·s)}. First-order in RX, nucleophile in excess or not in the RDS. Move a slider: the numbers are this situation, not a canned story.

Calculator

Inputs

Outputs

  • Rate r0.00020 mol/(L·s)
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ORG-06 · reactor
00:0 / 00:08

Narration of this film

First-order in RX, nucleophile in excess or not in the RDS.

Rate-determining ionisation to a carbocation. Tertiary and resonance-stabilised RX.

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