PROCEDURE FOR THE SELECTIVE HYDROGENATION FROM DIOLEFINKOHLENWASSERSTOFFEN TO OLEFINKOHLENWASSERSTOFFEN

09) OE PATENTSCHRIFT® No. of 328417 @ patentees: SNAH PBOGETTI S-P-A. IN MILAN (ITALY) @ article: PROCEDURE ZÖB SELECTIVE ONE HITDRIEHONG VCN DIOLEFINKOHLENWASSERSTOFFEN Z0 OLEFINKOHLENWÄSSEBSTOFFEH ©Zusatz to patent No. @Ausscheidung out: @|pAngemeldet to: 1973 07 26, 6587/73 @Ausstellungspriorität: @ (§) ® Unionspriorität: ITALY (IT), 1972 07 27, 27492/72, BEANSPBUCHT © beginning of the patent duration: 1975 06 15 longest ones possible duration: § spent to: 1976 03 25 inventors: MOBELLI BORELLO IN SAN DONÄTO MILANESE (ITALY), DE HARCO FOHTÜNATO IN MILAN (ITALY) - @) dependence: (|fi) block letters, which were considered for the demarcation of the state of the art: DT-OS1593641, DT-PSl181700, OE-PS224616, ÜS-PS3408415 00 OdCOO - 2 - Nr.328417 the invention refers to a procedure for the selective hydrogenation from Diolefinkohlenwasserstoffen to Olefinkohlenwasser materials. It is already well-known to hydrogenate Diolefinverbindungen in presence from palladium catalysts to but thereby in each case a mixture from Olefinen and satisfied connections is received, without it would be possible⁵ to achieve a controlled selectivity toward a preferential formation from Olefinen to. For the achievement connections satisfied by satisfying results and for the prevention of a following hydrogenation of the Olefinverbindungen to were also already suggested partly deactivating the palladium catalyst u.zw by impregnating or by coprecipitation with salts of the elements lead, zinc, mercury, cadmium, thorium and tin. Thus for example the German patent specification Nr.1181700 describes three variants, after which a palladium catalyst poisoned with heavy metal ions is to be manufactured. The first variant plans the treatment of the palladium Metalles during or preferably after the reduction of the palladium salt with a connection supplying the heavy metal ions, the second variant runs out on a common precipitation of palladium connection and heavy metal ions of supplying connection and following reduction of the mixture, while as last variant the possibility is finally discussed of connecting the treatment of the palladium with the heavy metal ions supplying connection with the actual hydrogenation. In this connection is completely generally suggested, which basic material which can be hydrogenated, which suspends the palladium catalyst contains, adding suitable heavy metal a connection whereby the use of such special heavy metal compounds is recommended, which are soluble in hydrocarbons. With means which can be used as solvents for the heavy metal compound it will appropriately concern that likewise only organic solvents. The impregnation or coprecipitation methods mentioned is only difficult in practice however to implement, because the deactivation conditions of the catalyst (temperature, concentration of the deactivation salt, duration of treatment) are extremely critical. One works at reaction conditions, which deviate even only slightly from the optimal conditions, catalysts are received, which are either not selective or completely deactivated. Furthermore it is well-known that for the achievement of a catalyst with high selectivity the impregnation or coprecipitation treatment must be implemented at relatively high temperatures from 80 to 100OC. Such a treatment proves however frequently as unfavorably, in particular with the production of carrier catalysts. 30Überraschenderweise now found that with hydrogenation of Diolefinverbindungen to Olefinen one almost 100%ige selectivity reached can, if the hydrogenation is implemented at relatively low temperatures, which lie anyhow in a temperature range from 20 to 60oC, in presence of usual palladium catalysts, which are applied on calcium carbonate or barium sulfate on a carrier, for example if necessary, and added to the reaction mixture an aqueous solution of a zinc salt. The subject of the invention is thus a procedure for the selective hydrogenation from Diolefinkohlenwasserstoffen to Olefinkohlenwasserstoffen in presence of a catalyst on the basis of palladium, if necessary in presence of up to 0,5%, related to the weight of the Diolefinverbindung, ammonia, which are characterized by the fact that one adds an aqueous solution 40 of a zinc salt to the Diolefinkohlenwasserstoff which can be hydrogenated and the hydrogenation at temperatures from 20 to 60oC and pressures from 1 to 50 ata implements. In the procedure according to invention it is possible to reach Selektivitäten from up to 100% to without it would be necessary to submit the palladium catalyst to the hot impregnation or coprecipitation methods which is very expensive and complex. In the procedure according to invention the zinc salt is added simply 45 as aqueous solution continuously to the mixture which can be hydrogenated. Beside that managing mentioned procedure-moderate and economic advantages exhibits the procedure according to invention also the preference/advantage that the life span according to invention of the catalyst used in the procedure is larger at same selectivity values than the life span of well-known deactivated catalysts. 50Nach the procedure according to invention can be led the material which can be hydrogenated and the zinc salt with continuous test attempts again and again across the catalyst, whereby always outstanding Selektivitäten is obtained. The anion of the zinc salt does not have influence on the selectivity, but is it to be preferred that the salt exhibits a high solubility in water. In this connection nitrate, 55 acetate and oxalate proved the chloride, sulfate, as very suitably. The quantity of added salt can amount to from 0,01 to 5%, preferably from 0,01 to 2%, related to the weight of the Diolefinkomponente. The minimum quantity at water, which is necessary for a satisfying reaction process, is given by that quantity, which is sufficient for the loosening of the zinc salt on the reaction conditions. This corresponds to 60 a water/a zinc salt weight ratio of at least 1: 1. On the other hand it is appropriate, _ a 3 - Nr.328417 water/zinc salt weight ratio of at the most 50: to use 1, in order to obtain a satisfying reaction rate. It is favourably, the reaction mixture additionally an amine, generally ammonia, to cause in very low portions preferably in quantities of under 0,5%, related to the weight of the Diolefinkomponente,⁵ although also higher portions of up to unfavorably do not affect 20 and 30% the conversion. The invention can be applied to continuous or intermittent procedure guidance within a broad temperature range from for example 20 to 60oC and a large pressure range from for example 1 to 50 ata. Those the reaction mixture which can be added quantity of salt depends indicated 10 ranges within that managing on the reaction rate, i.e. on the hydrogen printing and the temperature as well as on the effectiveness of agitating. In the procedure according to invention the hydrogen absorption of the reaction mixture stops, as soon as one of the double bonds was hydrogenated to a simple connection. Even when long leaving the mixture untouched with the reaction conditions, out-reacted, no substantial further hydrogenation enters more. 15Das procedures according to invention is more near illustrated in the following remark examples. Example: Cyclopentadien became in presence of 2 Gew. - % of a palladium catalyst (5%Pd on CaCOs as Katalysatorträger) with 30oC hydrogenates. That autoclaves became 0.2 Gew. - % ammonia, 0.2 Gew. - % zinc acetate dihydrate and 0.4 Gew. - % water added. Reactor contents were agitated by means of an agitator, which exhibited a hollow shank for the recirculation of hydrogen. The hydrogen printing was held^20kg/cm2. The reaction process was supervised gaschrqmatographisch on in regular intervals of pulled samples. After 90 min was observed no more hydrogen absorption. The selectivity on Cyclopenten, expressed by the relationship Cyclopenten ---------1---£------------------- (mol %), Cyclopenten + Cyclopentan amounted to 99,4. From the parent compound Cyclopentadien was present practically nothing more in the reaction mixture. After further 90 min long staying of the reaction mixture on the reaction conditions lay the³⁰ selectivity still over 99%. Beispiel2: The procedure way was kept by example 1, but added water in a quantity of 1%. After consumption of the parent compound Cyclopentadien the selectivity on Cyclopenten in the received product 99.2% amounted to and remained practically constantly to this value, even after long lasting staying of the product on the reaction conditions. 35Vergleichsbeispiel: One worked in accordance with example 1, but was added no water. The selectivity on Cyclopenten amounted to after using up the parent compound Dicyclopentadien 89%. If the product further 30 min on the reaction conditions was left, then the selectivity fell on 74%, because Cyclopentan formed, and after further 30 min fell the selectivity on 60%. Beispiele3 and 4: In the procedure way indicated in example 1 Isopren and 40 Pentadien were hydrogenated. After the complete consumption of the Diolefine mixtures were received from Olefinisomeren with Selektivitäten from 99,1 and/or 98,7%.

PATENT CLAIMS 1st procedures for the selective hydrogenation from Diolefinkohlenwasserstoffen to Olefinkohlenwasserstoffen in presence of a catalyst on the basis of palladium, if necessary in presence of up to 0,5%, related to the weight of the Diolefinverbindung, ammonia, thus that one adds 50 the Diolefinkohlenwasserstoff an aqueous solution of a zinc salt which can be hydrogenated and the hydrogenation at temperatures from 20 to 60oC and pressures from 1 to 50 ata implements. 2. Procedure according to requirement 1, thus that one the weight ratio from water to zinc salt to a value of at least 1: 1 holds. 3. Procedure according to requirement 1 or 2, thus that one adds the zinc salt in 55 of a quantity from 0,01 to 5%, related to the weight of the Diolefinverbindung.

Pressure: Ing.E.Voytjech, Vienna