PT86577B - PROCESS FOR THE DESTROYMENT OF LOW TEMPERATURE CHLORINE PRODUCTS - Google Patents

Abstract

1. Process for destroying chlorinated organic products containing more than 2 carbon atoms, in which these products are brought into contact with a bath of at least one chloroaluminate, characterized in that the initial concentration of the chlorinated organic products in the bath is 4000 ppm or less and preferably 2000 ppm or less.

Description

The present invention relates to a process for the destruction of chlorinated organic products having more than 2 carbon atoms, characterized by the fact that these products are contacted with a bath of at least one chloraluminate.

it is possible to use different chloraluminates or their mixtures. For example, potassium, lithium, sodium and calcium, strontium or ammonium chloroaluminates can be used.

In the present descriptive range of chloroaluminate, any mixture of anhydrous aluminum chloride with one or more metal chlorides is defined.

sodium chloroaluminate, which is preferably used, means a mixture of aluminum chloride and sodium chloride in any proportions and not just the equiuclecular mixture. The sodium chloroaluminate may also contain lithium and / or potassium chloride. You can therefore have any mixture of aluminum chloride, sodium chloride and lithium chloride which is called sodium and lithium chloraluminate.

It is also preferred that sodium chloroaluminate contains at least 50 mole% of aluminum chloride and our melting point is less than 200 ° C.

The invention is of interest to all chlorinated organic products that have more than 2 carbon atoms but is especially useful for aliphatic, cyclic, aromatic monocyclic or polycyclic and heterocyclic products. The invention is particularly concerned with perchlorinated aliphatic products and, among aromatic products, nolichlorobiphenyls.

The amount of chlorinated organic products to be destroyed is advantageously less than 5000 ppm of chloroaluminate and, preferably, less than 2000 nnm.

These products do not present any shape. In particular, they may be in a solid phase, for example absorbed over activated carbon.

The process according to the present invention consists in promoting the contact of the chlorinated product with the chloraluminate bath.

When the chlorinated nroclute is in a solid phase, the latter can be poured into the chloraluminate bath, preferably agitated. We try to keep the bath in the molten state, possibly by heating. The same procedure is applied if the chlorinated products are in a liquid phase. In most cases, the chlorinated products that are sought to be used are alone or in a mixture with light chlorinated products and / or carrier gases.

For example, these can be combustion gases;

then there is nitrogen containing carbon dioxide, carbon oxide and chlorinated products and, eventually, oxygen. But it can also be any gas mixture from any process.

It is preferred that the chlorinated products are in an anhydrous phase. The gas containing the chlorinated products will be dried in contact with an absorbent, for example, alumina or glyc-1.

Derois makes contact with this gaseous phase which contains the chlorinated products which it is intended to destroy with chloroaluminate using any means to make contact between a liquid phase and a gas phase. This wheel will only be a column of rats or filled. It is also possible to introduce the gas phase into a stirred vessel containing chloraluminate by means of a tube that dips or by a pipe that reaches deep into the vessel.

The different chlorinated organic products must be returned between the liquid and variant phases of the chloroaluminate bath. Products that accompany these chlorinated products can be used in the same rare way. A column of plates or filler can be used to ensure circulation and continuous agitation of the liquid and gaseous phases and good contact between the gaseous products and the chloraluminate bath. It is also possible to work with a series of agitated reactors. The chlorinated organic products are kept in contact with the chloraluminate bath for the time necessary for their destruction. The residence time varies between remote limits but is generally between a few minutes and a few hours.

Although if we work at any temperature since the chloraluminate is liquid, it is preferable to work at a temperature below 3CO ° C and, preferably, between 200 ° and 3C0 ° 0.

The rate of destruction of chlorinated products, particularly aromatics, increases with the temperature of chloraluminate.

in the gaseous phase of the chloraluminate bath - they are

contract - light products resulting from the decomposition of the chlorinated products that are sought to be destroyed; nor example, carbon tetrachloride and / or hexachloroethane. In the variant phase of the chloraluminate bath, there are no chlorinated organic products that were sought to be destroyed. When the chloraluminate bath is analyzed after having respected the contact between chlorinated products and chloraluminate, there are no traces of the organic products that it was trying to destroy.

It is also possible to periodically purge the rare chloraluminate bath to avoid the accumulation of insoluble or ross-containing products in suspension in the bunho. In this nurga, there are also no traces of chlorinated organic products. There is, therefore, the disappearance of the classic products that were sought to be destroyed.

In accordance with a preferred embodiment of the present invention, one or more O-metals chosen from the reducing metals such as, for example, aluminum or zinc, is added to the chloroaluminate bath. node whose average particle size is less than 5CC micrometers. If metals are used, chlorinated organic products are eliminated as previously but with a markedly lower speed, on the order of several times to several tens of times higher than the previous speed.

There is a reverse consumption of metal (or metals), which means that chloride is formed by absorbing chlorine to chlorinated organic products when it is destroyed. There is no unusual limit to the amount of metal to be introduced into the chlor-aluminum. It is preferred to use knotted aluminum; always add up to 5 or 10 ^{e /} in weight of aluminum knot to the heat-6 / roaluminate bath. It is verified that the speed of destruction of the chlorinated products increases with the amount of aluminum knot and the temperature of the chloraluminate bath. It is preferable to shake the bath so that the metal knot is very smooth in the bath. The metal chloride or the metal chlorides that are produced must not mix with the chloraluminate bath or be subdivided between the liquid and gaseous phases. If saric is needed, metal chlorides can be removed from the gas phase by treating it with a hydroxide such as caustic soda or caustic stick.

The following examples illustrate the present invention:

ΕΣΞΜρΐΟ_1

In an electrically heated 1 liter nirex flask, equipped with a propeller shaker that rotates at 300 revolutions per minute, 500 g of aluminum chloroaluminate are introduced whose ratio in moles A101 - q.

NaCl

Heat the product to 20 ° C, stir and add 0.2 g of hexachlorobenzene and 0.1 g of decachlorobiphenyl. After 1 hour at 200 ° C, the molten bath is washed for 15 minutes with a flow rate of 50 liters / hour of Ν _π , which is then washed in a washer bottle containing 100 ml of hexane.

The chlorinated organic compounds in the final bath as well as in the hexane are dosed by gas chromatography.

The results obtained are shown in Table 1 c

EOEOT.O_2

The same test is carried out, but in addition, 5 μl of fine aluminum rhodium (4 (υΗΙΝΕΥ umin 4b) is added to the chloraluminuminate bath. Years at 200 ° C and a current flow of 50 liters / h of N ₂ for 15 minutes, a sample is taken from the bath and hexane for analysis.

The results obtained are also shown in Table 1.

TABLE_1 t;

JPRODU-! jTOS ^ j ORGANT iCOS

CIjORAjDOS f 1 j t!

j ^c 6 ^ci 6;

DCBP *!

j j!

! j! BATH! Hexane! Product!

! . . . J _c .! J disappear!

, start], end,, eido!

13.2!

j

0.40!

j

SEM Al

WITH 5% of Al

200

100

J »111 j! 41.3 j

J t

J J t! ! Z of

BATH ih _exano i

----------. nexano.p ^^

-j initial Jfinai; íreciS

37.7 Z!

I

58.3 Z!

t

200

100 i

129 j

! 3.8 j t t t f {

3.5

0.2

J f!

J J; jUX '. JjV

We work with the same device used in Examples 1 and 2, but the operating conditions are modified:

- bath temperature: 250 0

- level of chloraluminate bath: 500 g

- addition of $ 5 aluminum foil (^ ECnlKEY XY 4b)

- test duration: 2 hours

- duration of the nitrogen chain massage after 2 hours: 15 minutes

- initial addition of: 500 mg of hexaelorobenzene

500 mg of decachlorobiphenyl.

The results obtained are shown in Table 2.

EXAMPLE 4

This is the same test as in Exemrlo 3 but its duration is 4 hours.

The results obtained are shown in Table 2.

TABLE 2! T • ·! PRODU-! DURATION 2 H! TOS!

! ORGANIC- !!

! COS! ^I0 ihexai

1CLORA-! . . . ’,!

! DC6 .miciáÇfínal, j j t ~! ! Z's!

™ ° hexane! ^^!

'desapa- ’________ireciao ♦

DURATION 4 H, disappear;;; -; j F Jrecido, initial, final.

J j j J j j 1 j 1 1 t ú t j 2.5! j 0.7 j j j j j j 0.3 t j 0.1 £ £ £ 1 ! C, HCl _c j ! 10! 5 1 t t 1.5 t 1.3 £ 1 j D J j t t » j ! 1 I 1 | C, C1 I 500 j 8! 3 J 97.8 j 500 J 1.3 j 3 £ 99.15 £ • b b | j ! £ j J t I £ DCBP j 500 j 6! 0.2 j 98.8 I 500 1 3 j 0.16 £ 99.4 £ ! j £ j J t £ r £ £ £ PS * t J 0.02! 0.00 2! j I 0.1 T . 0.008! £ J j J j j j t ! J t

Claims (7)

Claims 1. - Process for the destruction of chlorinated organic products having more than 2 carbon atoms, characterized by the fact that these products are contacted with a bath of at least one chloraluminate. 2. Process according to claim 1, characterized in that the chloroaluminate is sodium chloroaluminate. 3. Process according to claim 2, characterized in that the sodium chloroaluminate contains at least 50 mole% of aluminum chloride. 4. - Process according to any one of the claims 1 to 3, characterized in that the temperature of the chloraluminate bath is below 300 ° C and is preferably between 200 ° and 300 ° C. 5. - Process according to any one of the claims 1 to 4, characterized in that the chloroaluminate contains at least one powdered metal. 6. A process according to claim 5, characterized in that the metal is preferably aluminum. 7. - Process according to any one of the claims 5 or 6, characterized in that the average particle size of the powder is less than 500 / z ..