SU771080A1 - Method of naphthalene purification - Google Patents

Description

54) METHOD FOR CLEANING NAFTALINE

t

This invention relates to the field of naphthalene purification used in organic synthesis.

A known method of cleaning naphthalene E by passing naphthalene vapor in a stream of inert gas at a temperature of 130-200 ° C through an adsorbent layer - zeolite tcr A containing cations A, Sn Cr, Mn, cations of metals I, II or iron subgroup groups of the periodic system or their mixtures 1,

The closest in technical essence is the method of cleaning naphthalene by passing naphthalene vapor in a stream of inert gas at a temperature of 150-200 ° C through an adsorbent layer - a type X zeolite containing Na, Ca, 20 cations.

AlS sn-ff SoC Ni2-,

Cr

or their mixture

2

The naphthalene cleaning process is carried out in a stream of gas at a temperature of 150-200 ° C, passing naphtha-25 linine vapor through a column filled with zeolite. At the outlet of the adsorption column, the naphthalene is cooled and isolated in crystalline form. After adsorption, the zeolite is purged with toxm gas, and 30

then regenerated by blowing air, gradually raising the temperature to. The disadvantage of this method is the low selectivity of zeolites containing these cations with respect to thionaphthene.

The aim of the invention is to increase the purification rate by more completely removing thionaphthene.

The goal is achieved by the described method of cleaning the 31ft oil by passing naphthalene vapor in the air or inert gas at a temperature of 150-200 ° C through an adsorbent of type X zeolite containing cations selected from the group H. SaCh Mn, L15% Sn Co, N i, their mixtures and additionally cations

Si

or

These adsorbents make it possible to purify naphthalene from the most difficult to remove impurity-thionaphthene and to obtain a technical grade refined naphthalene, which is currently not produced in the USSR in the Soviet Union.

The characteristics of the used adsorbents and the limits of the content of cations in them are given in Table. 1 and 2.

The naphthalene cleaning process is carried out in the following manner. Molten naphthalene is fed to the evaporator, which receives air or inert gas. The naphthalene-gas mixture obtained is passed through an adsorption column filled with zeolite at a temperature of 150-200 ° C. On contact

Characteristics of zeolites used to purify naphthalene from thionaphtene. Limits of the content of introduced cations

Zeolite is regenerated. First, Pro). One naphthalene stripping from the intergranular space of a zeolite by a gas flow at a temperature of 180–200 ° C. After that, water vapor or O-xylene in an amount of 20 wt.% By weight of the zeolite is passed through the zeolite layer in a gas flow. The desorption of the displacer and impurities is carried out by blowing with air with a gradual increase in temperature to 320–350 ° C at a rate of 50 ° C / h until there is no desorption product in the exhaust gas.

Various types of naphthalene-containing raw materials are subjected to purification from thionaphthene on zeolites: pressed naphthalene, an artificial mixture composed of naphthalene, indan, indene, benzonitrile, thionaphthene, 2-methylnaphthalene and indole, as well as sublimated naphthalene containing thionaphthene, indan and 2-methylnaphthalene;

Example, Artificial mixture of composition,%: naphthalene 97.15; indole 0.4, iidan 0.4; indene 0.4; benzonitrile 0.35; 2-methylnaphthalene 0.50; thionaphthene 0.60 and 0.20 other compounds in the molten state are fed into the naphthalene vapor with the surface of the adsorbent selectively adsorbing naphthalene impurities, including thionaphthene, and the naphthalene is practically not adsorbed and freely pro- walks through a layer of zeolite. At the outlet of the column, naphthalene is captured and analyzed.

Table

Table 2

a vaporizer (temperature 200 ° C) where dry nitrogen enters.

The obtained vapor-gas mixture is passed through an adsorption column filled with zeolite CuNaX containing 15.88% Cu. Purification temperature is 150 ° C, naphthalene concentration in the vapor-gas mixture is 0.353 g / l, gas velocity is 831 h, adsorbent bed in the column is 160 mm, column diameter is 18 mm, zeolite weight is 30 g.

0 purification of naphthalene to a naphthalene: zeolite ratio of 1: 1.5, a product was obtained containing%: thionaphthene -0,100,2-methylnaphthalene 0.021,

PRI me R 2 Cleaning

, sublimated naphthalene, imgadium crystallization temperature of 79.7 s and containing 0.62% of thionaphthene. As an adsorbent, a CuCaNaX zeolite containing 13.12% of Cu is used, the temperature of the experiment is 150-160 ° C, and

0 gas (air) speed 563 h, naphthalene concentration in gas 0.42 g / l. When cleaning up to naphthalene:: zeolite 1: 5, the purified product of thionaphthene does not contain and has a temperature

5 crystallization 80,10 ° C,

Example 3. The raw materials and experimental conditions are similar to those described in example 2. Zeolite FeCaNaX containing 1.19% Fe is used as the adsorbent. At a ratio of naphthalene; zeolite 1:: 4,5 receive a product that does not contain thionaphthene and has a crystallization temperature of 80.14 ° C.

Example 4, Olrieu and test conditions are similar to those described in Example 2. ZeColite FeCaNaX containing 1.74% Fe was used as the adsorbent. When the naphthalene: zeolite ratio is 1: 1.1, a product containing 0.08% thionaphthene and having a crystallization temperature of 80.04 ° C is obtained.

PRI me R 5. The raw material for cleaning is a pressed naphthalene ESMZ with a crystallization temperature of 79, containing,%: 0.145 indole, 0.124 2-methylnaphthalene, 0.014 indene, and 0.948 thionaphthene. The ontJTa conditions are similar to those described in Example 2. The adsorbent zeolite FeCaNaX contains 1.19% Fe. The conditions of the experiment are similar to those described in Example 2, the naphthalene: zeolite ratio is 1: 1, 7. The obtained product containing 0.12% of thionauten and having a crystallization temperature of 80.0

The present method of cleaning naphthalene from thionaphthene has an advantage over the known one, which consists in improving the quality of the product obtained due to more complete removal of thionaphthene from naphthalene.

In tab. 3 shows the results of purification of various naphthalene-containing raw materials from thionaphthene according to known and proposed methods, Table 3

Claims (1)

Claim The method of purification of naphthalene by passing vapors of naphthalene in a stream of air or inert gas at a temperature of 150-200 ° C through a layer of adsorbent-zeolite type X containing cations selected from the group Na *, Ca ¹ *, Mn ² * *, AI ³ *, Sn ⁴ *, Co ² - *, Ni ^{z +} , C g ³ *, or a mixture thereof, characterized in that, in order to increase the degree of purification, an adsorbent is used, additionally containing Syninyl Fe ³ * cations