https://www.sciencemadness.org/smwiki/api.php?hidebots=1&days=14&limit=50&target=Category%3AChemical_compounds&action=feedrecentchanges&feedformat=atomSciencemadness Wiki - Changes related to "Category:Chemical compounds" [en]2024-03-29T07:47:04ZRelated changesMediaWiki 1.25.1https://www.sciencemadness.org/smwiki/index.php?title=Cyanoguanidine&diff=15648&oldid=15253Cyanoguanidine2024-03-28T18:41:34Z<p></p>
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<td colspan='2' style="background-color: white; color:black; text-align: center;">Revision as of 18:41, 28 March 2024</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>   }}</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>   }}</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>}}</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>}}</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>'''Dicyanamide''' or '''2-cyanoguanidine''' (IUPAC name), is an organic chemical compound, a nitrile derived from [[guanidine]]. It is a dimer of [[cyanamide]], with the formula '''C<sub>2</sub>H<sub>4</sub>N<sub>4</sub>'''.</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>'''Dicyanamide<ins class="diffchange diffchange-inline">''', '''dicyandiamide</ins>''' or '''2-cyanoguanidine''' (IUPAC name), is an organic chemical compound, a nitrile derived from [[guanidine]]. It is a dimer of [[cyanamide]], with the formula '''C<sub>2</sub>H<sub>4</sub>N<sub>4</sub>'''.</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>The name "2-cyanoguanidine" or just "cyanoguanidine" is often chosen for this compound in literature, as dicyanamide (also known as dicyanamine) is also the name for the anionic species  [N(CN)<sub>2</sub>]<sup>−</sup>, which may form 2-cyanoguanidine on formal addition of ammonia.</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 name "2-cyanoguanidine" or just "cyanoguanidine" is often chosen for this compound in literature, as dicyanamide (also known as dicyanamine) is also the name for the anionic species  [N(CN)<sub>2</sub>]<sup>−</sup>, which may form 2-cyanoguanidine on formal addition of ammonia.</div></td></tr>
<tr><td colspan="2" class="diff-lineno" id="L147" >Line 147:</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>: 2 CaCN<sub>2</sub> + H<sub>2</sub>O + OH<sup>-</sup> → (H<sub>2</sub>N)<sub>2</sub>C=N-CN + 2 Ca<sup>2+</sup> + OH<sup>-</sup></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>: 2 CaCN<sub>2</sub> + H<sub>2</sub>O + OH<sup>-</sup> → (H<sub>2</sub>N)<sub>2</sub>C=N-CN + 2 Ca<sup>2+</sup> + OH<sup>-</sup></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="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>After the boiling is complete, the fertilizer suspension is taken off the heat and filtered to remove the insoluble products. However, even if the resulting filtrate is clear, calcium hydroxide will still be present in said filtrate (solubility of Ca(OH)<sub>2</sub> is 0.066 g at 100 °C and its solubility increases with the decrease in temperature), and thus needs to be removed, to prevent it from interfering with the recrystallization of cyanoguanidine. While it's possible to precipitate it by adding small amounts of dil. sulfuric or phosphoric acid, the best route to remove the dissolved calcium is by bubbling [[carbon dioxide]] into the filtrate. This will cause the calcium to precipitate out of the solution as [[calcium carbonate]], and as a bonus will also remove the foul smelling sulfurous contamination. Thus, this step should be done either outside or in a fumehood. The pH should be measured throughout the process, and must be maintained at 8 or above. The filtrate is concentrated and then allowed to cool, which causes the cyanoguanidine to crystallize as rhombic crystal aggregates or needle-like crystals.</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>After the boiling is complete, the fertilizer suspension is taken off the heat and filtered to remove the insoluble products. However, even if the resulting filtrate is clear, calcium hydroxide will still be present in said filtrate (solubility of Ca(OH)<sub>2</sub> is 0.066 g<ins class="diffchange diffchange-inline">/100 ml </ins>at 100 °C and its solubility increases with the decrease in temperature), and thus needs to be removed, to prevent it from interfering with the recrystallization of cyanoguanidine. While it's possible to precipitate it by adding small amounts of dil. sulfuric or phosphoric acid, the best route to remove the dissolved calcium is by bubbling [[carbon dioxide]] into the filtrate. This will cause the calcium to precipitate out of the solution as [[calcium carbonate]], and as a bonus will also remove the foul smelling sulfurous contamination. Thus, this step should be done either outside or in a fumehood. The pH should be measured throughout the process, and must be maintained at 8 or above. The filtrate is concentrated and then allowed to cool, which causes the cyanoguanidine to crystallize as rhombic crystal aggregates or needle-like crystals.</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>A good procedure was described by SM user Diachrynic: Commercial calcium cyanamide fertilizer prills containing around 50% CaCN<sub>2</sub> with the rest being mostly calcium carbonate are boiled for 30 minutes with twice their weight in water, hot filtered and the filtrate left to crystallize. The needle shaped crystals are recovered and the filtrate reused for the next run, being topped off to the required volume. The yield is usually ~30% for the first extraction and around ~50% for subsequent runs. A more detailed description is provided in the forum thread [http://www.sciencemadness.org/talk/viewthread.php?tid=157156 here].</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>A good procedure was described by SM user Diachrynic: Commercial calcium cyanamide fertilizer prills containing around 50% CaCN<sub>2</sub> with the rest being mostly calcium carbonate are boiled for 30 minutes with twice their weight in water, hot filtered and the filtrate left to crystallize. The needle shaped crystals are recovered and the filtrate reused for the next run, being topped off to the required volume. The yield is usually ~30% for the first extraction and around ~50% for subsequent runs. A more detailed description is provided in the forum thread [http://www.sciencemadness.org/talk/viewthread.php?tid=157156 here].</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="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>The reaction of [[thiourea]] with [[copper(II) oxide]] or [[copper(II) carbonate]] will yield dicyanamide.The procedure is described as following:</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>The reaction of [[thiourea]] with [[copper(II) oxide]] or [[copper(II) carbonate]] will yield dicyanamide. The <ins class="diffchange diffchange-inline">reaction in the </ins>procedure is described as following:</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>: 2 (H<sub>2</sub>N)<sub>2</sub>C=S + 2 CuO → (H<sub>2</sub>N)<sub>2</sub>C=N-CN + 2 CuS + H<sub>2</sub>O</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>: 2 (H<sub>2</sub>N)<sub>2</sub>C=S + 2 CuO → (H<sub>2</sub>N)<sub>2</sub>C=N-CN + 2 CuS + H<sub>2</sub>O</div></td></tr>
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</table>Mabushttps://www.sciencemadness.org/smwiki/index.php?title=Rubidium_nitrate&diff=15647&oldid=15060Rubidium nitrate2024-03-28T17:59:23Z<p></p>
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<td colspan='2' style="background-color: white; color:black; text-align: center;">Revision as of 17:59, 28 March 2024</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>==Preparation==</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>==Preparation==</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>Can be easily prepared by dissolving rubidium carbonate in nitric acid, the recrystallized from the resulting solution. [[Rubidium hydroxide]] can also be used.</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>Can be easily prepared by dissolving rubidium carbonate in nitric acid, the recrystallized from the resulting solution. [[Rubidium hydroxide]] can also be used<ins class="diffchange diffchange-inline">, albeit this reaction is very exothermic, so the neutralization should be done slowly</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>: Rb<sub>2</sub>CO<sub>3</sub> + 2 HNO<sub>3</sub> → 2 RbNO<sub>3</sub> + H<sub>2</sub> + CO<sub>2</sub></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>: Rb<sub>2</sub>CO<sub>3</sub> + 2 HNO<sub>3</sub> → 2 RbNO<sub>3</sub> + H<sub>2</sub> + CO<sub>2</sub></div></td></tr>
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