https://www.sciencemadness.org/smwiki/index.php?title=Grignard_reagent&feed=atom&action=historyGrignard reagent - Revision history2024-03-28T16:50:40ZRevision history for this page on the wikiMediaWiki 1.25.1https://www.sciencemadness.org/smwiki/index.php?title=Grignard_reagent&diff=10850&oldid=prevMabus at 14:37, 1 April 20192019-04-01T14:37:28Z<p></p>
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<td colspan='2' style="background-color: white; color:black; text-align: center;">Revision as of 14:37, 1 April 2019</td>
</tr><tr><td colspan="2" class="diff-lineno" id="L13" >Line 13:</td>
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<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>*The inert gas tank you're using must be checked before use  </div></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>*The inert gas tank you're using must be checked before use  </div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>*Make sure your heating source works</div></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>*Make sure your heating source works</div></td></tr>
<tr><td class='diff-marker'>−</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>*Dry your reagents thoroughly</div></td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>*Dry your reagents <ins class="diffchange diffchange-inline">and solvents </ins>thoroughly</div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div> </div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins class="diffchange diffchange-inline">===Drying solvents===</ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins class="diffchange diffchange-inline">*To prepare dry solvents that can be used in the preparation of Grignard reagents, always check the compatibility of the solvents with the drying agent</ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins class="diffchange diffchange-inline">*Akali metals can be used to dry ethers, saturated hydrocarbons</ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins class="diffchange diffchange-inline">*Drying solvents works best under reflux</ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins class="diffchange diffchange-inline">*Drying solvents under inert gas limits the amount of dissolved gases that may interfere with the reaction</ins></div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>===Setting up your installation===</div></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>===Setting up your installation===</div></td></tr>
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<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>===Obtaining the Grignard reagent===</div></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>===Obtaining the Grignard reagent===</div></td></tr>
<tr><td class='diff-marker'>−</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>*In a [[dropping funnel]] from the installation add the inert solvent (ether) and pour a small amount on the magnesium from the reaction flask; if you don't have a dropping funnel, you can use a septum to cover the glass joint and use a syringe or <del class="diffchange diffchange-inline">canula </del>to inject the ether in the reaction flask</div></td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>*In a [[dropping funnel]] from the installation add the inert solvent (ether) and pour a small amount on the magnesium from the reaction flask; if you don't have a dropping funnel, you can use a septum to cover the glass joint and use a syringe or <ins class="diffchange diffchange-inline">cannula </ins>to inject the ether in the reaction flask</div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>*Add the organic halide or the ketone/aldehyde in the dropping funnel and dissolve it in the leftover ether  </div></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>*Add the organic halide or the ketone/aldehyde in the dropping funnel and dissolve it in the leftover ether  </div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>*Turn on the stirring and introduce an activator, like [[iodine]], 1-bromopropane or 1,2-dibromoethane in the reaction flask, over the ether-magnesium suspension, which will cause the magnesium the react, and the ether will begin to reflux; an external heat source like a [[heat gun]] can be used to control the effervescence</div></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>*Turn on the stirring and introduce an activator, like [[iodine]], 1-bromopropane or 1,2-dibromoethane in the reaction flask, over the ether-magnesium suspension, which will cause the magnesium the react, and the ether will begin to reflux; an external heat source like a [[heat gun]] can be used to control the effervescence</div></td></tr>
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</table>Mabushttps://www.sciencemadness.org/smwiki/index.php?title=Grignard_reagent&diff=7402&oldid=prevMabus: Created page with "{{Stub}} '''Grignard reagents''' are alkyl, vinyl, or aryl-magnesium halides, with the general formula R-MgX, where R is the organic group and X the halogen (Chlorine|Cl..."2017-08-06T16:28:24Z<p>Created page with "{{Stub}} '''Grignard reagents''' are alkyl, vinyl, or aryl-<a href="/smwiki/index.php/Magnesium" title="Magnesium">magnesium</a> halides, with the general formula R-MgX, where R is the organic group and X the halogen (Chlorine|Cl..."</p>
<p><b>New page</b></p><div>{{Stub}}<br />
'''Grignard reagents''' are alkyl, vinyl, or aryl-[[magnesium]] halides, with the general formula R-MgX, where R is the organic group and X the halogen ([[Chlorine|Cl]], [[Bromine|Br]], [[Iodine|I]]).<br />
<br />
==Properties==<br />
Grignard reagents are solid compounds, having a coloration between white and yellow, mainly due to impurities and side reaction products. They react violently with [[water]], [[acid]]s, [[alcohol]]s, [[aldehyde]]s, [[amine]]s, [[ester]]s, [[halocarbons]], [[ketone]]s, [[nitro compound]]s, but are stable and soluble in ''very'' dry organic solvents, like [[ether]]s ([[diethyl ether]], [[1,4-Dioxane|dioxane]], [[Tetrahydrofuran|THF]]) and hydrocarbons like [[benzene]], [[toluene]], [[hexane]]. Other incompatible solvents are [[acetonitrile]], [[carbon disulfide]], [[Dimethyl sulfoxide|DMSO]], etc.<br />
<br />
==Synthesis==<br />
To obtain a Grignard reagent, you will need to do the following steps:<br />
<br />
===Preparing glassware and other equipment===<br />
*Make sure your glassware is perfectly clean and dry, with no traces of moisture or other contaminants<br />
*Check the glassware for any defects, cracks<br />
*The inert gas tank you're using must be checked before use <br />
*Make sure your heating source works<br />
*Dry your reagents thoroughly<br />
<br />
===Setting up your installation===<br />
*Add the magnesium flakes/powder in the reaction flask and a stir bar; a stir bar should also be added in one or both dropping funnels from your installation to aid dissolving the organic halide<br />
*Connect the rest of the final installation<br />
*Using a vacuum pump remove the air inside the installation, close the vacuum valve then introduce the inert gas ([[nitrogen]] or [[argon]]) inside the installation<br />
*Repeat the procedure 2-4 times<br />
*Turn on water cooling<br />
<br />
===Obtaining the Grignard reagent===<br />
*In a [[dropping funnel]] from the installation add the inert solvent (ether) and pour a small amount on the magnesium from the reaction flask; if you don't have a dropping funnel, you can use a septum to cover the glass joint and use a syringe or canula to inject the ether in the reaction flask<br />
*Add the organic halide or the ketone/aldehyde in the dropping funnel and dissolve it in the leftover ether <br />
*Turn on the stirring and introduce an activator, like [[iodine]], 1-bromopropane or 1,2-dibromoethane in the reaction flask, over the ether-magnesium suspension, which will cause the magnesium the react, and the ether will begin to reflux; an external heat source like a [[heat gun]] can be used to control the effervescence<br />
*Once the reaction has calmed, slowly add the ether solution to the reaction flask and add the flask in a heating bath until your reaction has completed<br />
*After completion, turn off the heating, cooling, remove the flask from the bath and installation, then extract your compound<br />
<br />
===Notes===<br />
*The use of inert gas may not be required if you can keep the interior of the installation perfectly dry; however, for most organometallic compounds, having an inert environment is crucial, as many compounds are air-sensitive<br />
*A drying tube filled with calcium chloride can be used to limit the moisture that enters the installation<br />
*If you're using a [[glovebox]] instead of a [[Schlenk line]], the process is much simpler<br />
*Any leftover Grignard reagent should be neutralized with alcohol<br />
<br />
==Uses==<br />
Organometallic reagents are used in [[Grignard reaction]]s to obtain various alcohols, like [[tert-Butanol|tert-butanol]] from [[acetone]].<br />
<br />
: CH<sub>3</sub>-MgX + (CH<sub>3</sub>)<sub>2</sub>C=O → (CH<sub>3</sub>)<sub>3</sub>C-O-MgX<br />
: (CH<sub>3</sub>)<sub>3</sub>C-O-MgX + H<sub>2</sub>O → (CH<sub>3</sub>)<sub>3</sub>C-OH + Mg(OH)X<br />
<br />
Reaction with [[carbon dioxide]] will give the carboxylic salt of the organic group + the carbon from the CO<sub>2</sub>.<br />
<br />
: 2 R-MgX + CO<sub>2</sub> → (R-COO)<sub>2</sub>Mg + MgX<br />
<br />
Reaction with an anhydrous metal halide, like [[zinc chloride]], will give the organometallic compound of said metal.<br />
<br />
:2 R-MgX + ZnX<sub>2</sub> → ZnR<sub>2</sub> + 2 MgX<sub>2</sub><br />
<br />
This process is known as transmetalation.<br />
<br />
==Handling==<br />
===Safety and storage===<br />
Grignard reagents are extremely sensitive to water and moisture. Work must be done under inert atmosphere.<br />
<br />
Grignard reagents aren't very stable and should be used as soon as possible. Short term storage can be done in a flask filled with dry argon, kept in a cold place, like a fridge.<br />
<br />
===Disposal===<br />
Grignard reagents are best neutralized by adding them in a non-polar solvent, like [[toluene]], where small amounts of alcohols are added to safely neutralize the Grignard reagent. This procedure must be done in a low oxygen environment, as there's still a small risk of fire.<br />
<br />
==See also==<br />
*[[Organolithium reagent]]<br />
*[[Drying solvents]]<br />
<br />
==References==<br />
<references/><br />
===Relevant Sciencemadness threads===<br />
*[http://www.sciencemadness.org/talk/viewthread.php?tid=18110 Grignard reagent problem]<br />
*[http://www.sciencemadness.org/talk/viewthread.php?tid=13844 Drying Ether for Grignard]<br />
*[http://www.sciencemadness.org/talk/viewthread.php?tid=65113 Grignard reagent compatibility]<br />
<br />
[[Category:Chemical compounds]]<br />
[[Category:Organometallic compounds]]<br />
[[Category:Materials unstable in acidic solution]]<br />
[[Category:Materials that react with water]]<br />
[[Category:Air-sensitive materials]]<br />
[[Category:Unstable materials]]<br />
[[Category:DEA SS List]]</div>Mabus