<p><b>二硼酸</b>是一種無機化合物，化學式為B<sub>2</sub>(OH)<sub>4</sub>，它可用於製備有機硼酸。</p>
<h2><span id=".E5.90.88.E6.88.90"></span><span id="合成">合成</span></h2>
<p>三氯化硼和乙醇的反應最初於1931報導，反應生成二甲氧基氯化硼（B(OCH<sub>3</sub>)<sub>2</sub>Cl），後來，一種引入B-B鍵的新方法由此製備了四甲氧基二硼（B<sub>2</sub>(OCH<sub>3</sub>)<sub>4</sub>）：</p>
<dl><dd><dl><dd>BCl<sub>3</sub>   <span><span><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle {\ce {-&gt;[{\text{+ }}{\ce {CH3OH}}][-{\text{ }}{\ce {HCl}}]}}}">
  <semantics>
    <mrow class="MJX-TeXAtom-ORD">
      <mstyle displaystyle="true" scriptlevel="0">
        <mrow class="MJX-TeXAtom-ORD">
          <mrow class="MJX-TeXAtom-REL">
            <munderover>
              <mo>→</mo>
              <mpadded width="+0.611em" lspace="0.278em" voffset="-.24em">
                <mo>−<!-- − --></mo>
                <mrow class="MJX-TeXAtom-ORD">
                  <mtext> </mtext>
                </mrow>
                <mrow class="MJX-TeXAtom-ORD">
                  <mtext>HCl</mtext>
                </mrow>
              </mpadded>
              <mpadded width="+0.611em" lspace="0.278em" voffset=".15em">
                <mrow class="MJX-TeXAtom-ORD">
                  <mtext>+ </mtext>
                </mrow>
                <mrow class="MJX-TeXAtom-ORD">
                  <msubsup>
                    <mtext>CH</mtext>
                    <mrow class="MJX-TeXAtom-ORD">
                      <mn>3</mn>
                    </mrow>
                    <mrow class="MJX-TeXAtom-ORD">
                      <mspace width="0pt" height="0pt" depth=".2em"></mspace>
                    </mrow>
                  </msubsup>
                  <mtext>OH</mtext>
                </mrow>
              </mpadded>
            </munderover>
          </mrow>
        </mrow>
      </mstyle>
    </mrow>
    <annotation encoding="application/x-tex">{\displaystyle {\ce {-&gt;[{\text{+ }}{\ce {CH3OH}}][-{\text{ }}{\ce {HCl}}]}}}</annotation>
  </semantics></math></span></span>   B(OCH<sub>3</sub>)<sub>2</sub>Cl   <span><span><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle {\ce {-&gt;[{\text{+ }}{\ce {Na}}][-{\text{ }}{\ce {NaCl}}]}}}">
  <semantics>
    <mrow class="MJX-TeXAtom-ORD">
      <mstyle displaystyle="true" scriptlevel="0">
        <mrow class="MJX-TeXAtom-ORD">
          <mrow class="MJX-TeXAtom-REL">
            <munderover>
              <mo>→</mo>
              <mpadded width="+0.611em" lspace="0.278em" voffset="-.24em">
                <mo>−<!-- − --></mo>
                <mrow class="MJX-TeXAtom-ORD">
                  <mtext> </mtext>
                </mrow>
                <mrow class="MJX-TeXAtom-ORD">
                  <mtext>NaCl</mtext>
                </mrow>
              </mpadded>
              <mpadded width="+0.611em" lspace="0.278em" voffset=".15em">
                <mrow class="MJX-TeXAtom-ORD">
                  <mtext>+ </mtext>
                </mrow>
                <mrow class="MJX-TeXAtom-ORD">
                  <mtext>Na</mtext>
                </mrow>
              </mpadded>
            </munderover>
          </mrow>
        </mrow>
      </mstyle>
    </mrow>
    <annotation encoding="application/x-tex">{\displaystyle {\ce {-&gt;[{\text{+ }}{\ce {Na}}][-{\text{ }}{\ce {NaCl}}]}}}</annotation>
  </semantics></math></span></span>   B<sub>2</sub>(OCH<sub>3</sub>)<sub>4</sub>   <span><span><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle {\ce {-&gt;[{\text{+ }}{\ce {H2O}}][-{\text{ }}{\ce {CH3OH}}]}}}">
  <semantics>
    <mrow class="MJX-TeXAtom-ORD">
      <mstyle displaystyle="true" scriptlevel="0">
        <mrow class="MJX-TeXAtom-ORD">
          <mrow class="MJX-TeXAtom-REL">
            <munderover>
              <mo>→</mo>
              <mpadded width="+0.611em" lspace="0.278em" voffset="-.24em">
                <mo>−<!-- − --></mo>
                <mrow class="MJX-TeXAtom-ORD">
                  <mtext> </mtext>
                </mrow>
                <mrow class="MJX-TeXAtom-ORD">
                  <msubsup>
                    <mtext>CH</mtext>
                    <mrow class="MJX-TeXAtom-ORD">
                      <mn>3</mn>
                    </mrow>
                    <mrow class="MJX-TeXAtom-ORD">
                      <mspace width="0pt" height="0pt" depth=".2em"></mspace>
                    </mrow>
                  </msubsup>
                  <mtext>OH</mtext>
                </mrow>
              </mpadded>
              <mpadded width="+0.611em" lspace="0.278em" voffset=".15em">
                <mrow class="MJX-TeXAtom-ORD">
                  <mtext>+ </mtext>
                </mrow>
                <mrow class="MJX-TeXAtom-ORD">
                  <msubsup>
                    <mtext>H</mtext>
                    <mrow class="MJX-TeXAtom-ORD">
                      <mn>2</mn>
                    </mrow>
                    <mrow class="MJX-TeXAtom-ORD">
                      <mspace width="0pt" height="0pt" depth=".2em"></mspace>
                    </mrow>
                  </msubsup>
                  <mtext>O</mtext>
                </mrow>
              </mpadded>
            </munderover>
          </mrow>
        </mrow>
      </mstyle>
    </mrow>
    <annotation encoding="application/x-tex">{\displaystyle {\ce {-&gt;[{\text{+ }}{\ce {H2O}}][-{\text{ }}{\ce {CH3OH}}]}}}</annotation>
  </semantics></math></span></span>   B<sub>2</sub>(OH)<sub>4</sub></dd></dl></dd></dl><h2><span id=".E5.8F.8D.E5.BA.94"></span><span id="反应">反應</span></h2>
<p>二硼酸在90 °C以上脫水，生成一氧化硼，220 °C時完全失水。</p><p>它是一種還原劑，在水中緩慢放出氫氣。</p>
<h2><span id=".E5.8F.82.E8.80.83.E6.96.87.E7.8C.AE"></span><span id="参考文献">參考文獻</span></h2>

<!-- 
NewPP limit report
Parsed by mw1406
Cached time: 20230505045040
Cache expiry: 1814400
Reduced expiry: false
Complications: []
CPU time usage: 0.299 seconds
Real time usage: 0.509 seconds
Preprocessor visited node count: 6477/1000000
Post‐expand include size: 111384/2097152 bytes
Template argument size: 24763/2097152 bytes
Highest expansion depth: 29/100
Expensive parser function count: 11/500
Unstrip recursion depth: 0/20
Unstrip post‐expand size: 5914/5000000 bytes
Lua time usage: 0.084/10.000 seconds
Lua memory usage: 5754040/52428800 bytes
Number of Wikibase entities loaded: 0/400
--><!--
Transclusion expansion time report (%,ms,calls,template)
100.00%  327.783      1 -total
 62.76%  205.726      1 Template:Chembox
 21.13%   69.276      1 Template:Chembox_Identifiers
 20.83%   68.284      1 Template:Reflist
 17.95%   58.848      1 Template:Chembox_Properties
 14.27%   46.762      1 Template:硼化合物
 13.74%   45.028      1 Template:Navbox
 11.10%   36.394      1 Template:Cite_encyclopedia
 10.46%   34.286     87 Template:Chembox_entry
  8.51%   27.886      1 Template:Chembox_Hazards
-->
**二硼酸**是一種無機化合物，化學式為 B2(OH)4，它可用於製備有機硼酸。

## 合成

三氯化硼和乙醇的反應最初於 1931 報導，反應生成二甲氧基氯化硼（B (OCH3)2Cl），後來，一種引入 B-B 鍵的新方法由此製備了四甲氧基二硼（B2(OCH3)4）：

　
: : BCl3   ${\ce {->[{\text{+ }}{\ce {CH3OH}}][-{\text{ }}{\ce {HCl}}]}}$   B(OCH3)2Cl   ${\ce {->[{\text{+ }}{\ce {Na}}][-{\text{ }}{\ce {NaCl}}]}}$   B2(OCH3)4   ${\ce {->[{\text{+ }}{\ce {H2O}}][-{\text{ }}{\ce {CH3OH}}]}}$   B2(OH)4

## 反應

二硼酸在 90 °C 以上脫水，生成一氧化硼，220 °C 時完全失水。

它是一種還原劑，在水中緩慢放出氫氣。

## 參考文獻
13675-18-8