suzuki偶联反应中加水不加水的问题

4-Methoxy-2'-methylbiphenyl . o-Tolylboronicacid, 10.0 g(73.6 mmol), 16.8 g(71.8 mmol) of 4-iodoanisole, and 200 mL of acetoneare combined in a 1-L, three-necked flask equipped with an efficient stirbar,two stoppers, and a reflux condenser attached to a gas-flow adapter with astopcock. Potassium carbonate, 25.0 g(0.180 mol), is dissolved in 200 mL of water in a separate 250-mL Schlenkflask. In a third flask (25-mL Schlenk flask) 3.30 mg (0.02 mmol, 0.2%) of palladiumacetate is dissolved in 10 mL of acetone. All three flasks are then thoroughly degassed by four freeze-pump-thawcycles. Under an argonback flow, one of the stoppers on the three-necked flask is replaced with arubber septum, and the carbonate and catalyst solutions are added via cannulato form a biphasic mixture. The top layer turns brown upon addition of thecatalyst. The septum is replaced with the glass stopper and three additionalfreeze-pump-thaw cycles are applied. The flask is then backfilled with argon,and the reaction is brought to reflux under a positive argonpressure. After 2 hr at reflux the heat source is removed and the reaction isallowed to cool. By this time the brown color has faded and the reaction is atriphasic mixture with copious amounts of palladiumblack floating between the layers. The reaction is transferred to a 1-Lseparatory funnel and extracted into diethyl ether(3 × 100 mL). The organic layers are combined, washed with water (1 × 100 mL)saturated with sodium chloride , and dried over magnesiumsulfate . Solvent is removed with a rotary evaporator to yield ayellow oil which is distilled (125-130°C,0.10 mm) to give 12.8 g of 4-methoxy-2'-methylbiphenylas a colorless oil (90.3% yield).

在钯催化下，有机硼化合物与有机卤素化合物进行偶联反应，这就提供了一类常用和有效的合成碳-碳键化合物的方法，我们称之为Suzuki 偶联反应，或Suzuki-Miyaura 偶联反应。

碱的话多用K2CO3，也有K3PO4、 Na2CO3、CsF、Cs2CO3、t-Bu-Na等等,一般不用NaHCO3。碱的强度对大位阻的2,4,6-三甲基硼酸的偶联反应的影响次序是: Ba(OH)2>NaOH >K3PO4 >Na2CO3 >NaHCO3。但是, 用弱碱往往比用强碱反应干净一些。

1。苯的同系物侧链活化会被高锰酸钾统一氧化成苯甲酸

用氢氧化钠处理成苯甲酸钠就可以在水中充分溶解。最后分液可以得到苯。

2.减压蒸馏，甲苯挥发性较好，容易脱除。

3.活性炭吸附可以将味道去除得较彻底。

4.蒸馏时加入少量比甲苯沸点还高的溶剂于溶液中，蒸馏时分开甲苯和该溶剂

去除甲苯中的苯甲酸

加入NaOH溶液后，与苯甲酸反应，使苯甲酸成为可溶于水的钠盐，这样就与甲苯分开了。

甲苯无色澄清液体。有苯样气味。有强折光性。能与乙醇、 乙醚、丙酮、氯仿、二硫化碳和冰乙酸混溶，极微溶于水。相对密度0.866。凝固点-95℃。沸点110.6℃。折光率 1.4967。闪点（闭杯） 4.4℃。易燃。蒸气能与空气形成爆炸性混合物，爆炸极限1.2%～7.0%（体积）。低毒，半数致死量（大鼠，经口）5000mg/kg。高浓度气体有麻醉性。有刺激性。

除去苯中的甲苯的方法

[学妹] 能用酸性KMnO4溶液，甲苯会被氧化为苯甲酸。因为苯甲酸会溶于甲苯，所以还必须在此基础上加入氢氧化钠溶液，苯甲酸和氢氧化钠溶液反应生成可溶的苯甲酸钠，而苯不溶于水。此时采用分液就可以分离，达到除去甲苯的目的了。

苯，甲苯，二甲苯不都是液体吗？怎么挥发呢？挥发成气体吗？

苯，甲苯，二甲苯都是有机溶剂，有机溶剂易挥发

在苯中去除甲苯

你加入的氢氧化钠是水溶液，苯甲酸钠是一个有机盐，是可以溶解在水溶液中的，而苯与水是不互溶的，所以可以与苯用分液的方法分离。

苯是非极性的，而苯甲酸钠在水溶液中电离形成苯甲酸根负离子，是极性的，它们不互溶。有机物和有机物也并不是都能相互溶解的，也大体遵循相似相溶的规律。