**溴化苄**（又稱**苄基溴**或**α-溴代甲苯**），分子式C6H5CH2Br或C7H7Br，是一種苯环被溴甲基取代的芳香化合物。它可通过甲苯在室温下发生溴化反应（二氧化锰为非均相催化剂）进行制备。溴化苄在有机合成中可以用于醇和羧酸基团的保护基。具有強烈的催淚性和令人不舒服的刺鼻氣味，如果沒有保持空氣流通，會刺激呼吸道和皮膚引發皮炎和蕁麻疹，粘著眼睛。吸入濃度高的溴化苄蒸氣可以引致暫時胸部緊束、支氣管炎和肺水腫。由於有這些特性，常常在戰爭中作為氣體武器。

性質
--

### 物理性質

常溫下為無色液體並揮發，溶于大多数有机溶剂，在水中慢慢水解为苯甲醇和溴化氢。折射率略高於琥珀，密度低於鎂。

### 化學性質

#### 親核取代反應

DABCO與溴化苄可在充分過量的DABCO存在下發生親核取代,使DABCO这种叔胺转化成季铵盐，这是门秀金反应的一个典型例子。通過測定用不同濃度DABCO作起始原料時反應液的電導率變化情況，並用 *Guggenheim*法 （页面存档备份，存于） 分析，得知反應對DABCO的級數。

#### 與甲醛次硫酸氫鈉反應

與甲醛次硫酸氫鈉作用，發生 *S*-烷基化生成碸：

{\displaystyle {\rm {\ NaHOCH\_{2}SO\_{2}+2C\_{6}H\_{5}CH\_{2}Br\rightarrow [C\_{6}H\_{5}CH\_{2}]\_{2}SO\_{2}+NaBr}}}{\displaystyle {\rm {\ +CH\_{2}O+HBr}}}
也可發生 *O*-烷基化，得到亞磺酸酯。

#### 有機合成

溴化苄可用于有機合成中的保护基反应，如保护醇羟基形成醚，保护羧基形成酯键。

ROH + C6H5CH2Br + R'3N → ROCH2C6H5 + R'3N•HBr
RCOOH + C6H5CH2Br + R'3N → RCOOCH2C6H5 + R'3N•HBr

製備
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苄基溴可以通过自由基卤代反应制备，如甲苯和溴素反应：

溴化苄也可通过Wohl–Ziegler溴化反應制备，但N-溴代丁二醯亞胺无法直接与甲苯反应，必须在催化剂如过氧化物的作用下，才可得到64%产量的溴化苄。。

用途
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在有機合成中用於保護如醇和羧酸等化合物当中的羥基。也可用作發泡劑和防腐劑。

參見
--

* 氯化苄
* N-溴代丁二醯亞胺

參考來源
----

1. ↑  *Merck Index*, 11th Edition, **1142**
2. 1 2 3 .  [2011-04-28]. （原始内容存档于2019-06-26）.
3. ↑ .  [2011-04-27]. （原始内容存档于2010-07-17）.
4. ↑ .  [2011-04-27]. （原始内容存档于2019-06-10）.
5. ↑  Holleman, A. F.; Wiberg, E. *Inorganic Chemistry*. Academic Press: San Diego, 2001. ISBN 0-12-352651-5.
6. ↑  Schmid，H and Karrer, P. Helv. Chim. Acta. 1946, **29**: 578.  缺少或`|title=`为空 (帮助)

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**苄基化合物** |
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| --- | --- | --- | --- | --- |
| BnH |  |  |  | He |
| BnLi | Be | Bn3B | BnBnBnCN | BnNH2 | Bn2OBnOH | BnF | Ne |
| BnNa | Mg | Al | Bn4Si | BnPH2 | Bn2SBn2S2（世界语：）BnSH | BnCl | Ar |
| BnK | Ca | Sc | Bn4Ti | V | Cr | Mn | Fe | Co | Ni | Cu | Zn | Ga | Ge | As | BnSeH | BnBr | Kr |
| Rb | Sr | Y | Bn4Zr | Nb | Mo | Tc | Ru | Rh | Pd | Ag | Cd | In | Sn | Bn3Sb | Bn2TeBn2Te2 | BnI | Xe |
| Cs | Ba | 镧系 | Bn4Hf | Ta | W | Re | Os | Ir | Pt | Au | Bn2Hg | Tl | Pb | Bn3Bi | Po | At | Rn |
| Fr | Ra | 锕系 | Rf | Db | Sg | Bh | Hs | Mt | Ds | Rg | Cn | Nh | Fl | Mc | Lv | Ts | Og |
|  |  | ↓ |  |  |
| 镧系 | La | Ce | Pr | Nd | Pm | Sm | Eu | Gd | Tb | Dy | Ho | Er | Tm | Yb | Lu |
| 锕系 | Ac | Th | Pa | U | Np | Pu | Am | Cm | Bk | Cf | Es | Fm | Md | No | Lr |

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