JPH04210653A - Production of 1,1-dichloro-2,2,3,3,3-pentafluoropropane - Google Patents

Abstract

PURPOSE:To produce the subject substance in a high reaction rate and in a high selective degree even at a relatively low temperature by hydrogenating 1,1,1-tichloro-2,2,3,3,3-pentafluoropropane in the presence of an Ir series catalyst. CONSTITUTION:1,1,1-Trichloro-2,2,3,3,3-pentafluoropropane is reacted with hydrogen gas in the presence of an Ir series catalyst at 50-200 deg.C for 5-100sec to produce the subject substance. The Ir series catalyst is preferably carried in an amount of 0.05-5wt.% on a carrier such as alumina or active carbon. It is not required that the whole amount of the catalyst is Ir, but the catalyst may contain the other element of the group VIII, a high melting point element such as rhenium, tungsten, niobium or lanthanum, gold, silver, copper. etc., for the improvement in the life of the catalyst. The subject substance is used as a substitute for Freon 113.

Description

[Detailed description of the invention]

[00011

[Industrial Application Field] The present invention relates to 1,1-dichloro-2゜2, 3. 3. The present invention relates to a suitable method for producing 3-pentafluoropropane. This compound can be used in a wide range of applications such as blowing agents, refrigerants, and cleaning agents, similar to the conventionally widely used fluorocarbons. [0002] [Prior Art] Conventionally, methods for producing such compounds include:
The reaction of tetrafluoroethylene and dichlorofluoromethane produces 1,1-dichloro-2,2,3,3,3-pentafluoropropane and 1,1-dichloro-1,2,2,3°3-pentafluoropropane. There are known ways to obtain it. [0003] Furthermore, a method has been proposed in which pentafluoropropanes are reacted with hydrogen in the presence of a hydrogenation catalyst, as shown in JP-A-2-204443, but in this method, it is difficult to control the reaction. As a result, various compounds with different degrees of hydrogenation can be obtained. Therefore, when trying to obtain a compound such as 1,1-dichloro-2,2,3,3,3-pentafluoropropane,
In order to sufficiently increase the selectivity of this compound, it is necessary to sacrifice the reaction rate, and this cannot be said to be an industrially preferable production method. [0004]

[Specific Means for Solving the Problems] In view of the problems of the conventional method, the present inventors conducted intensive studies and found that when an iridium-based catalyst is used as a hydrogenation catalyst,
．． The present invention was achieved by discovering that 1-dichloro-2,2,3,3,3-pentafluoropropane can be obtained with high selectivity and high reaction rate. [0005] That is, the present invention provides 1. 1. 1,1-dichloro-2,2,3,3,3-, which is characterized by reacting 1-trichloro-2,2,3,3,3-pentafluoropropane with hydrogen in the presence of an iridium catalyst. This is a method for producing pentafluoropropane. [0006] In the method of JP-A-2-204443, group VIII elements, rhenium, zirconium, and tungsten are exemplified as hydrogenation catalysts, and in the examples, ruthenium, rhodium, palladium, platinum, and cobalt are used as group Vllll elements. , nickel is used, but 1
, 1-dichloro-2,2,3,3,3-pentafluoropropane has the highest selectivity of 75.3%, the reaction rate is 7169%, and the yield is 54. ．． It is as low as 1%. [00071 In the present invention, an iridium-based catalyst is used as the hydrogenation catalyst, but alumina, activated carbon, etc. are preferably used as the carrier, and the supporting method is not particularly limited, and any commonly used method can be used. good. The supported amount is preferably in the range of 0.05 to 5% by weight. Also,
Before using the catalyst, it is preferable to treat the catalyst with hydrogen in advance. [00081 The iridium-based catalyst used in the present invention does not necessarily need to contain iridium in its entirety; it can be modified by using other metals, and other elements of group VIII or other metals may be used to improve the catalyst life. rhenium,
High melting point elements such as tungsten, niobium, lanthanum, gold,
Additions of silver, copper, etc. are also useful. [00091] In the method of the present invention, the ratio of hydrogen to the raw material is preferably in the range of 0.5 to 4, particularly preferably about 2. If the reaction rate is less than this range, the reaction rate of the starting organic material will not be sufficient, and if it exceeds this range, highly hydrogenated products will increase. [00101 reaction is preferably a gas phase reaction, and the reaction temperature is 5
A range of 0 to 200°C is preferred. Below this range, the reaction rate of the starting organic material is low, and above this range, highly hydrogenated products increase. The contact time is usually 0.
A range of 1 to 300 seconds is applied, more preferably 5 to 1
The range is 00 seconds. [0011] Reaction in a liquid phase is also possible, and can be carried out using an alcoholic solvent such as ethanol or without a solvent, but separation of the catalyst and solvent is required, and reactions involving solvents occur. Because of these problems, it is best to decide whether to carry out the process in the gas phase or in the liquid phase, taking into account these advantages and disadvantages. [0012] 1 used as raw material, 1. 1-Trichloro-2,2,3,3,3-pentafluoropropane can be easily produced by carrying out an addition reaction in the presence of an anhydrous aluminum chloride catalyst using tetrafluoroethylene and trichloromethane as raw materials, and is usually 99% purity
The above are used. By-products produced in the reaction include 1-chloro-2,2,3,3,3-pentafluoropropane, 2. 2. 3. 3. 3-pentafluoropropane, 2, 2. 3. 3-tetrafluoropropane is the main component, and its amount can be extremely reduced by lowering the reaction temperature. [0013]

[Examples] The present invention will be explained in detail with reference to Examples below. [0014] Preparation Example 1 0.5% of the weight of activated carbon is iridium chloride based on the weight of the metal component in pure water of the same volume as activated carbon.
was dissolved. After immersing activated carbon in this solution for 12 hours, water was evaporated to dryness. This catalyst was filled into a SUS reaction tube, calcined at 400°C for 12 hours under a nitrogen stream, cooled to 200°C, hydrogen introduced, and reduced at 300°C for 12 hours. [0015] Example 1 Using the activated carbon-supported iridium catalyst prepared in Preparation Example 1 (supported amount: 0.5% by weight), the length was 40 cm, and the inner diameter was 2.5 cm.
30 cc of catalyst was filled into a reaction tube made of SUS304 and placed in an electric furnace. [0 0 1 6] Hydrogen and starting material 1, 1. passed through a water trap and then a glass trap cooled in a dry ice methanol bath. 1-trichloro-2.
2, 3, 3. 3-pentafluoropropane was gasified at flow rates of 60 cc/min and 30 cc/min, respectively, and introduced into the reaction tube. The reaction temperature was 100°C and the contact time was 34 seconds. Reaction product C was collected and analyzed using gas chromatography and NMR. The results are shown in Table 1. [0 0 1 7] Examples 2 to 4 Reactions were carried out in the same manner as in Example 1, except that the catalyst and reaction conditions were as shown in Table 1. The results are shown in Table 1. [0 0 1 8] Comparative Examples 1 and 2 A reaction was carried out in the same manner as in Example 1, except that the catalyst and reaction conditions were as shown in Table 1. The results are shown in Table 1. [0 0 1 9]

[Table 1] ml 1al/1l42 1aI/lI! 43 1IIIIII! ! 44 ratio-1 alN2 touch brewing 1r! f Ir It Pd Pd Anti-carrier activated carbonActivated carbonActivated memberActivated carbon Hateful carbon reaction A I is an Ijojone mockery, this case one/A cry of impatience ■ [phase]》 Reaction rate Q0 79.8 51.3 99.9 99.9 62.5 99.9 Selection selectivity ■ σρiQ. 96.3 83.1 94.5 78.4 15.7 CPil-ro 3.7 13.6 4.0 11.6 43.1 G21cF crystal 3.3 1.5 10.0 40.3 Others 0 .9 - I [0 0 2 01 As is clear from the results in Table 1, according to the method of the present invention, the desired 1,1-diku mouth 2,
2, 3, 3. 3-pentafluoropropane can be produced with good selectivity, and the reaction rate is also good even at relatively low temperatures. [0 0 2 11

Effects of the Invention According to the present invention, 1,1-dichloro-2. 2, 3,
3. 3-pentafluoropropane can be produced in good yield. Continuation of Front Page (72) Inventor Takada Naomon Central Glass Co., Ltd. Tokyo Laboratory, 2805 Imafuku Nakadai, Kawagoe City, Saitama Prefecture

Claims (1)

[Claims] Claim 1: 1,1,1-trichloro-2,2,3.3
, 3-pentafluoropropane is reacted with hydrogen in the presence of an iridium catalyst.