dibromomethane

• ChemBase编号: 126964
• 分子式: CH2Br2
• 平均质量: 173.83458
• 单一同位素质量: 171.85232406
• SMILES: BrCBr
• Canonical SMILES: BrCBr
• InChI: InChI=1S/CH2Br2/c2-1-3/h1H2
• InChIKey: FJBFPHVGVWTDIP-UHFFFAOYSA-N

名称和登记号

名称

• IUPAC标准名: dibromomethane
• IUPAC传统名: dibromomethane
• 别名: 甲叉二溴; 二溴甲烷; 二溴甲烷 溶液; Methyl dibromide; Methylene bromide; Methylene dibromide; Refrigerant-30B2; Dibromomethane; Dibromomethane; Dibromomethane solution

登记号

• CAS号: 74-95-3
• EC号: 200-824-2; 200-659-6
• MDL号: MFCD00000168
• Beilstein号: 969143
• 默克索引号: 146061
• PubChem SID: 24871436; 24854398; 24893828; 162221288; 24884902
• PubChem CID: 3024
• CHEBI ID: 47077
• Chemspider ID: 2916
• Gmelin ID: 25649
• 医学主题词(MeSH): methylene+bromide
• 维基百科标题: Dibromomethane

理论计算性质

• 质子受体: 0
• 质子供体: 0
• LogD (pH = 5.5): 1.0393913
• LogD (pH = 7.4): 1.0393913
• Log P: 1.0393913
• 摩尔折射率: 22.0715 cm^3
• 极化性: 8.78044 Å^3
• 极化表面积: 0.0 Å^2
• 可自由旋转的化学键: 0
• 里宾斯基五规则: true

分子性质

理化性质

• 溶解度: 12.5 g L^-1 (at 20 °C) in water
• 外观: Colorless liquid
• 熔点: -52 °C(lit.); -52.70°C (220.45K); -53°C
• 沸点: 95.85 - 97.85°C (369 - 371 K); 96-98 °C(lit.); 96-98°C
• 闪点: 11 °C; 51.8 °F
• 密度: 2.477 g mL^-1; 2.477 g/mL at 25 °C(lit.); 2.495
• 折射率: 1.541; 1.5410; n20/D 1.541; n20/D 1.541(lit.)
• 蒸汽压: 34.9 mmHg ( 20 °C); 4.65 kPa (at 20.0 °C)
• 蒸汽密度: 6.05 (vs air)
• 亨利常数: 9.3 μmol Pa^-1 kg^-1
• 热容: 104.1 J K^-1 mol^-1

安全信息

• RTECS编号: PA7350000
• 欧盟危险性物质标志: 易燃性(Flammable) (F); 有毒(Toxic) (T); X; 有害性(Harmful) (Xn)
• 联合国危险货物编号: 1230; 2664; UN2664
• 德国WGK号: 1; 2
• 联合国危险货物等级: 3; 6.1
• 联合国危险货物包装类别(PG): 2; 3; III
• 危险公开号: 11-23/24/25-39/23/24/25; 20-52/53; R20, R52/53
• 安全公开号: 24-61; 7-16-36/37-45; S2, S24
• TSCA收录: 是
• 欧盟危险品索引: 602-003-00-8
• GHS危险品标识: GHS exclamation mark; GHS02; GHS06; GHS07; GHS08
• GHS警示词: WARNING; Danger; Warning
• NFPA704:
  

  0

  2

  0
• 半数致死量: >4 g kg^-1 (dermal, rabbit); 1 g kg^-1 (oral, rabbit); 3.738 g kg^-1 (subcutaneous, mouse)
• GHS危险声明: 332, 412; H225-H301-H311-H331-H370; H332-H412
• GHS警示性声明: 273; P210-P260-P280-P301 + P310-P311; P261-P273-P271-P304+P340-P312-P501A; P273
• 个人保护装置: Eyeshields, Faceshields, full-face respirator (US), Gloves, multi-purpose combination respirator cartridge (US), type ABEK (EN14387) respirator filter
• RID/ADR: UN 1230 3/PG 2; UN 2664 6.1/PG 2; UN 2664 6.1/PG 3
• 保存温度: 2-8°C

产品相关信息

• 纯度: ≥98.5% (GC); ≥99%; 99%; 99%, stab. with 50ppm BHT
• 浓度: 2000 μg/mL in methanol; 5000 μg/mL in methanol
• 级别: analytical standard; puriss.
• 包装: ampule of 1 mL; ampule of 1000 mg
• Empirical Formula (Hill Notation): CH2Br2

详细说明

Sigma Aldrich - 239992

包装
50 mL in glass bottle

Sigma Aldrich - D41686

包装
2 L in glass bottle
500 mL in glass bottle

Sigma Aldrich - 66730

Other Notes
与 Zn 和 TiCl4 共存的试剂，用于羰基化合物的亚甲基化1

参考文献

• For in situ formation of dibromomethyllithium by reaction with lithiated 2,2,6,6-Tetramethylpiperidine, A18712, and use in a one-pot ester homologation sequence, safer and more convenient than the classical Arndt-Eistert (diazomethane) method, see: Org. Synth. Coll., 9, 426 (1998):
  
• Reaction with NaHMDS generates monobromocarbene, which reacts with alkenes to give bromocyclopropanes: Synthesis, 201 (1972). It can also be generated by reaction with diethylzinc in the presence of O₂: J. Chem. Soc., Chem. Commun., 364 (1975).
• The Simmons-Smith reaction (see Diiodomethane, A15457) may be extended to the use of dibromomethane in the cyclopropanation of simple electron-deficient alkenes, using a reducing agent prepared from NiBr₂, NaI and Zn: Bull. Chem. Soc. Jpn., 56, 1025 (1983); or with CuCl/Zn: J. Org. Chem., 55, 2491 (1990).
• With TiCl₄/Zn, methylenation of ketones occurs, as a useful mild alternative to the Wittig reaction: Tetrahedron Lett., 23, 4293 (1982); Org. Synth. Coll., 8, 386 (1993). For a variant using Zn, CuCl and catalytic TiCl₄, see: J. Org. Chem., 54, 2388 (1989).
• With alcohols, formaldehyde acetals can be formed under phase-transfer conditions: Bull. Chem. Soc. Jpn., 66, 2149 (1993). Diols give methylenedioxy derivatives, which are components of many biologically-important molecules. For use of KF in DMF as base in the methylenation of catechols, see: Tetrahedron Lett., 3361 (1976). KOH in DMSO has been recommended for the methylenation of base-stable carbohydrate diols: Synthesis, 421 (1982). For the methylenation of ribonucleosides under phase-transfer conditions, see: Synthesis, 715 (1981).