DD291322A5 - PROCESS FOR PREPARING COPPER (II) OXALATE - Google Patents

Abstract

The invention relates to a process for the preparation of which can be used as a fine chemical, catalyst or as a catalyst and as a stabilizer sensitive polymers. The aim and object of the invention is to develop a process for the preparation of *, which ensures high product purity and yield with low energy, time and equipment technical effort. According to the invention, this is achieved by grinding the copper powder and crystalline oxalic acid in the room temperature in a milling aggregate using grinding aids whose grain size is greater than that of the copper powder until fully reacted. It is essential that in place of the copper powder compounds of copper in the form of oxides and carbonates can be used. It is also essential to the invention that corundum, quartz grains, silicon carbide or sea sand are added as grinding aids. {* Catalyst; Stabilizer; Product purity; Copper powder; Oxalic acid crystalline; Ball mill; grinding aids; Corundum; Quarzkoerper; silicon carbide; sea sand; Korngroesze}

Description

Application of the invention

The invention relates to a process for the preparation of copper (II) oxalate, which can be used as a fine chemical, catalyst or Katalysatorprecursor and as a stabilizer sensitive polymers.

Characteristic of the known state of the art

The preparation of copper oxalate is carried out in the prior art hitherto exclusively by wet chemical means by precipitation of the cold water insoluble salt. This happens z. B. by adding an excess of oxalic acid to a hot aqueous solution of copper (II) sulfate. The oxalic acid is added in solid form (Ullmann's Ezyklopadie der technischen Chemie, 4th ed., Vol. 15, Weinheim 1978, p 577). Also known is the precipitation with alkali metal oxalates. The disadvantage here is the formation of stable double salts of the formula Me ₂ Cu (C ₂ O ₄ I ₂ x 2H ₂ O, which impedes the production of an alkali-free Kupferoxalates and a high energy expenditure (Remy, textbook of Inorganic Chemistry, 4th and 5th Ed., II vol., Leipzig 1949, page 391.) Unlike the standard technical method of precipitation with oxalic acid, US Pat. No. 3,841,660 describes the preparation of copper oxalate by reacting a copper salt with iron oxalate, thereby attempting the very old process the production of so-called cement copper, ie the precipitation of copper powder from copper salt solutions by metallic iron, to transfer to the production of copper oxalate.The drawback is the insufficient purity of the product.

Object of the invention

The aim of the invention is to develop a process for the preparation of copper (II) oxalate, which ensures high product purity and high Ausboute with low energy and time.

Explanation of the essence of the invention The object of the invention is the process conditions of a simple, with low apparatus engineering Specify effort to process for the production of copper (II) oxalate. According to the invention the object is achieved in that copper powder and crystalline oxalic acid in the molar ratio Room temperature in a milling unit using grinding aids in an amount of 10-40 mass%,

based on the starting materials, the grain size of which is greater than that of the copper powder, are ground together until complete reaction.

Essential to the invention is that in place of the copper powder compounds of copper in the form of oxides and carbonates

can be used.

It is also essential that the grinding aids corundum, quartz grains, silicon carbide or sea sand are added. By the Mahlhilfsmittel a significant shortening of the grinding time is achieved by the fact that on the wall of the grinder

During the milling process settling copper layer is removed continuously. The grinding aids lead in this

Process for a mechano-chemical activation of the reaction products. The used in the grinding Grinding aids can be separated from copper (II) oxalate by simple dissolution in water and filtration. The obtained Copper ODE oxalate solution can be used directly for the preparation of supported catalysts. With the method according to the invention could be achieved for the first time that in a single-stage grinding process directly from the

pure metal or one of its oxides or carbonates and pure crystalline oxalic acid without special equipment beigeringem energy input copper (II) oxalate in high yield and product purity is produced.

After completion of the grinding process, the copper oxalate does not precipitate as a coarse dried product as in the precipitation process Filter cake, but in the necessary for further use as a catalyst or stabilizer finely dispersed form,

caused by the use of the grinding aid, as a texture promoter.

Below, the method according to the invention will be explained in more detail by means of exemplary embodiments.

-2- 291322 embodiments

example 1

In a ball mill, 6 g of electrolytic copper powder and 10 g of oxalic acid are ground for 3 hours by means of corundum balls. Pure crystalline copper (II) oxalate is obtained, as shown by a comparison of the X-ray diffractogram of the product with the diffraction pattern of pure commercial copper (II) oxalate. The yield is 98%.

Example 2

In a ball mill, 10 g of oxalic acid and 8 g of copper (II) oxide are added. After a grinding time of 2.5 hours with agate milling balls, a white, slightly bluish product is obtained, which according to its X-ray diffraction pattern is copper (II) oxalate, with a yield of 95%.

Example 3

In a ball mill, 22 g of a basic copper (II) carbonate are ground with 18.5 g of oxalic acid for 3 hours. After the end of the grinding, the starting substances can no longer be detected by X-ray analysis in the ground product. The diffraction reflections can be identified as those of the copper (II) oxalate. The yield is 96%.

Example 4

Add 8g of copper powder, 14g of oxalic acid and 5.5g of corundum to an agate ball mill. After 30 minutes, the metallic copper powder is completely converted into copper (II) oxalate, as shown by the X-ray diffraction diagram. The corundum particles are enveloped by layers of Kupferoxalats, as shown by scanning electron micrographs, which is otherwise achieved only in dragee drums, fluidized bed reactors, etc. at temperatures above the boiling point of water. The yield of copper (II) oxalate is 98%.

Belspiel5 11g of a basic copper (II) carbonate, 10 g of oxalic acid and 4 g of quartz chippings are placed in a ball mill and the products used are ground by means of porcelain balls. After a grinding time of 45 minutes, copper (II) oxalate is obtained with a yield of 95%.

Example 6

In a ball mill, 8 g of oxalic acid are ground with 9.5 g of copper (II) oxide with the addition of 5.3 g of sea sand as grinding aid for 60 minutes by means of porcelain balls. The yield of copper (II) oxalate is 92%.

Claims (4)

1. A process for the preparation of copper (II) oxalate, characterized in that the copper powder and crystalline oxalic acid in molar ratio at room temperature in oinem milling unit using grinding aids in an amount of 1Öbis40 parts by mass in%, based on the starting materials whose grain size greater than that of the copper powder is milled to complete implementation. 2. The method according to claim 1, characterized in that instead of the copper powder compounds of copper in the form of oxides and carbonates are used. 3. The method according to claim!, Characterized in that corundum, quartz grains, silicon carbide or sea sand are added as a grinding aid. 4. The method according to claim 1, characterized in that the grinding aids have been used preferably in an amount in the range of 20-30 parts by weight in%, based on the starting materials.