Method for preparing n-tetradecane under normal pressure

Abstract

The invention relates to a method for preparing n-tetradecane under normal pressure, which comprises the following steps of: (1) mixing glacial acetic acid, zinc powder and alkyl halides of the same grade; (2) dripping hydrochloric acid into the mixture, refluxing, precipitating and separating to obtain a liquid crude product of the n-tetradecane; (3) washing by using acid and alkali to obtain purified liquid of the n-tetradecane; and (4) distilling under reduced pressure to obtain a finished product of the n-tetradecane. The production process is simple, the zinc powder, bromoalkane and the hydrochloric acid are added at the temperature of below 110 DEG C under normal pressure, high-temperature and high-pressure reactions are not performed, and the process has low requirement on production equipment and low danger. In the method, a one-step synthetic mode of reducing the alkyl halides by using hydrogen atoms is adopted, and diethyl ether is replaced by sulfuric acid to remove unsaturated hydrocarbons and alcohols, the safety factor is high, and the condition is easy to control.

Description

technical field [0001] The invention belongs to the field of chemical reagents, and relates to a method for preparing even-numbered normal alkanes by reducing brominated alkanes with hydrogen atoms, especially a method for preparing n-tetradecane under normal pressure. Background technique [0002] N-alkane is a raw material for the production of surfactant linear alkylbenzene (LAB), which is separated from kerosene or diesel fractions in industrial production by molecular sieve method. As one of the key components of the environment-friendly liquid composition and one of the components of the diesel oil low temperature improver, it is being widely used. At the same time, n-paraffin monomers also have very important functions in the analysis fields of geology, crude oil and organic matter in atmospheric particulate matter. However, due to the different sources of n-alkanes, the composition of various n-alkanes is different, so that the products have different degrees of dif...

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Problems solved by technology

[0007] Among the above three methods, the first method has more complex process conditions, higher material requirements and larger investment scale for some equipment, and is only suitable for large-scale petrochemical industrial production; the second method is to use metal sodium as The reactants link symmetrical haloalkane, which is more dangerous to operate and has a lower safety factor; the third method is that the iodoalkane reactant itself has great volatility, and the crude product of the product needs to be extracted repeatedly with ether, which takes a long period and costs higher