Preparation method for one-time preparation of n-hexadecane in the following steps:
(1). Mix 1510.5 g (10 mol) of n-pentyl bromide and 3053.5 g (10 mol) of n-hexadecyl bromide to form a bromoalkane mixture, and set aside;
(2). Weigh 483 g (21 mol) of metallic sodium and cut it into small thin strips with an area of about 1 x 3 cm2, and set aside;
(3). In the reaction kettle put 50g of bromoalkane mixture as well as 20g of sodium metal, stirring to raise the temperature to 80 , relying on the reaction heating, and maintain the reaction temperature of 120 , and constantly dropwise addition of the remaining bromoalkane mixture, and add the sodium metal, maintain the micro reflux state, the addition is completed, control the temperature at 140 , constant temperature for 2 hours;
(4). Sequentially add 400 g of 95% ethanol as well as 1000 ml of water, split the organic matter, washed with water to neutral, dried with anhydrous magnesium sulfate, distilled to collect 260 ~ 280 fractions, the fraction plus 600 g of concentrated potassium sulfate washed to the acid layer light yellow, washed with water the organic phase to neutral, drying, through the fractional distillation column to collect 500 g of 96% of the n-decane, 600 g of 98% of the n-xyloxanes, the resulting n-alkane content of 96% to 98%.
Said n-pentane and n-hexadecyl bromide molar ratio is 1:1, the reactor is a three-ported flask consisting of a stirrer, a separatory funnel and a reflux condenser, said strong oxidizing agent is concentrated sulfuric acid or acidic potassium permanganate.
