DE1768543A1 - Process for the production of vinyl fluoride - Google Patents

Description

68054/1417 Troisdorf, May 21

Dynamit Nobel Aktiengesellschaft
Troisdorf / District Cologne

Process for the production of vinyl fluoride

It is known that vinyl fluoride can be produced by the direct addition of hydrogen fluoride to acetylene, that is to say in a similar manner to the way in which vinyl chloride has been produced for a long time and to the greatest possible extent by the addition of hydrogen chloride to acetylene. For both reactions, very similar catalysts, described in multiple modifications, are required, ie, mercury salts on activated carbon. However, the optimal temperature ranges for the two formally similar reactions are very different; in the manufacture of vinyl fluoride is advantageously remains below 100 ⁰ C, however, one needs to obtain a rapid course of the reaction in the production of vinyl chloride from 180 ° to 200 ° C. In the case of the two reactions, however, the lifetime of the catalyst, which is very important for the economic viability of the process, is very different. While the vinyl chloride

Synthesis in the technical equipment commonly used today

* - Lifetime of the catalytic converter reached up to several years *** Can be used in the manufacture of vinyl fluoride

Yy? so far only "such" from about 10 to a maximum of about 100 hours * "Achieve, since the activity of the catalyst drops very quickly and severe build-up of the catalyst occurs.

BATH ORIGINAL

According to BAS 1 259 329, there is a rapid reduction in activity of the catalytic converter, make sure that you see this Duration of the process process in increased * NaBe hoohaolekulare Deposits polymers and resins, their Entatehungauraache the contact of the heating gas with the metallic parts of the Reactor is.

The life of the catalytic converter can be increased significantly, if according to BAS 1 259 329 all inner surfaces of the reactor exclusively made of hydrogen fluoride resistant · «made of plastic, so that any influence of nets on the part of the reaction involved gases and the catalytic converter are switched off

Surprisingly, it has now been found that industrial vinyl fluoride production can also be carried out in metallic reactors, > · Β · those made of steel, stainless steel, chrome-nickel steel or Viokel, is possible if the reaction gases used and the related Catalyst are extremely dried

In this way, the deposition of high molecular weight polymers and resins, which up to now have shown a rapid decrease in activity in metallic reactors and strong build-up of the catalyst caused, can be avoided with certainty

For this, however, it is necessary that the acetylene not more than 100 mg H "0 / Hm * CgH", preferably from 0-30 mg / lm, the hydrogen fluoride not more than 100 ag H ₃ O / kg HP, preferably from 0- 20 mg / kg HF, and the residual moisture of the freshly filled catalyst not more than 0.05 J *,

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preferably from $ 0 - $ 0.01

Without this having already reached the upper limit, a service life of the catalyst of over 2,100 be achieved.

In order to use the catalyst as roll as possible and to achieve a high acetylene conversion, it is advisable to use several, e.g. three reactors connected in series · After e.g. 700 The operating time is always the first reactor with the oldest contact filling, which now has an operating time of 2,100 has reached, emptied and refilled. The newly filled reactor is then switched as the last reactor. After another 700 the next reactor is emptied, refilled and reconnected as the last reactor.

If this change is carried out after 700, it can go to in this way a practically complete conversion of the C-Hp is achieved weden. The operating time of each individual contact fill is then 2 100, but the used contact can easily be emptied even after this time, as there is practically no caking of the catalyst can be observed.

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Example!

The vinyl fluoride is prepared in three reactors connected in series made of chrome-oil steel. Each reactor, which contains 19 individual reactor tubes (45 × 2.5 × 1000 mm), is filled with a contact which, in a known manner, consists of activated carbon impregnated with mercury salts. The Eontakt at 100 ⁰ C and a vacuum of 2 - 3 mm Hg as long dried until the residual moisture only 0.01 i ".

The filling of the reactors with this Eontakt takes place below N_ flushing, so that the ingress of humidity with certainty is avoided. ; Knowi ·? ·

Hydrogen fluoride (0.95 kg /) with a residual moisture of 8 mg / kg HF and acetylene (0.9 nr /) with a residual moisture of 9 mg H "0 / N nr C_H" are mixed and with a cooling water Temperature of the reactors from 30 ~ 40 C to vinyl fluoride implemented.

The acetylene used is dried in a drying tower with active alumina before the vinyl fluoride synthesis. The acetylene-hydrogen fluoride mixture flows through the three reactors one behind the other, each of which has a different operating time of the contact filling, as can be seen below
Operating time of the contact filling

in the 1st reactor1 1,400 - 2,100 ^h in the 2nd reactor »700 - 1,400 ^h in the 3rd reactor! 0 - 700 ^h .

As soon as the first reactor has been filled · operating time

of ^{21 has} reached 100 h, this reactor is emptied and new

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filled * The "previous 2nd reactor will then be used as a 1 · reactor, the 3 · Reactor switched as 2nd reactor and the freshly filled reactor as 5th reactor.

The Replacing the oldest contact filling with a new contact filling in the manner described repeatedly

In this way it is possible to achieve an almost complete conversion of the acetylene to vinyl fluoride. The vinyl fluoride formed contains hur 0 $ £ maiiaal to 5 <f> acetylene. Since no more caking of the catalyst can occur with this procedure and, as a result, neither blockages within the SontakifÜllung can arise great difficulties in emptying the ¥ §rüchten contact, a steady and trouble-free operation is achieved in this way.

BATH ORIGINAL

Claims (1)

- 6 patent claims! 1 7ββ * ΐ /. ^ 1. Yerfahren for the production of vinyl fluoride by implementing iron Acetylene with hydrogen fluoride in a metallic reactor in the presence of a Mercury catalyst on activated carbon as Carrier material, characterized in that the When used, it has a residual moisture content of 0 * 0.05 % * of 0-0.01 $, the acetylene used has a residual moisture content of 0-100 mg / min, preferably 0-50 mg / B »and the hydrogen fluoride used has a residual moisture content of 0-100 mg / kg HF, preferably τοη 0-20 mg / kg Wf ₉ . 2. The method according to claim 1, characterized in that the implementation in steel, stainless steel, chrome-hiok steel or Hickel reactors he follows. 5. The method according to claim 1 and 2, characterized in that the formation of yinyl fluoride in several alternately one behind the other Reactors takes place » Dr.Ml/Ha. 109842 / H96 ßAD ORIGINAL