CS265748B1 - Double cobalt-magnesium cyclo-tetraphosphates and process for preparing them - Google Patents

Abstract

The present invention relates to novel cobalt tetrachlorophosphate double cobalt tetraphosphate compounds of the formula c-Co2-xMgxP40i2 'where x ranges from near zero to near two. It is prepared by crystallization in a dry melt atmosphere at a temperature above 1060 ° C, containing cobalt and magnesium cations in a Co / Mg molar ratio corresponding to (2-x) / x and further containing phosphate anions in an amount corresponding to P2O5 / (Co + Mg) 0.96 to 1.1 when solidified.

Description

The invention relates to new compounds of type double cyklotetrafosforečnanů kobaltnatohořečnatých formula ^{C CO} 2 ^M gx _x ^P 4 ⁰ 12 ^{y where x} ranges from values close to zero up to a value approaching the two.

Of the compounds of the condensed phosphate type having a single cation of a divalent metal and an oxide of the oxide (p) n to the corresponding metal, one known mostly cyclotetaphosphates (formula ^Me 2 ^lp 4 ° 12 ^{) and} 3 ^Gdnak higher linear phosphates (formula ^We n / 2 ^I 2 ^P n ^O 3 n 4 P * * ^{rak tons, u} is also in the case of cobalt condensed phosphates, where there exists both decaphthalic cyclotetaphosphate ( c-Co ^ P ^ O ^^^ ^tnk higher linear cobalt phosphates (Co ^ / 2 ^I 2 ^P n ° 3n + 1 ^{in the} case of magnesium compounds where higher linear phosphates exist ^{M M} 9n / ₂ ^H 2 ^P n ° 3n + PP ^{products with} cyclic tetraphosphate anions (c- ^Mg2P4O4 ) have the importance of double cyclotetaphosphates containing magnesium cations in addition to other divalent metal cations. However, these higher linear phosphates of divalent metals, whether single-cation or double-cation-double-cation, have some properties which are less suitable for their use. They are substances of amorphous, non-crystalline, glassy character, which are fragile. They are also relatively easily soluble and some even tend to be moisturized. Their thermal stability is limited by recrystallization temperatures (500-800 ° C). Due to the existence of simple higher linear (single-cation) phosphates and simple cyclotetaphosphates with the corresponding cation, and especially from a comparison of their properties, it is expected that double compounds of the cyclotetaphosphate type, where one of the cations is magnesium, will have completely different properties. It can be assumed that they will be far more appropriate than higher linear phosphates for all the contemplated uses of condensed phosphates to date.

The invention consists in that it provides double cyklotetrafosforečnany kobaltnatohořečnaté as novel compounds of the formula ^{C ~ i} - ^{'2-x M} 9x 4 ^P ^ i 2, ^{wherein X} 3 ^EV range from values approaching zero until two values close. The lower and upper limits for x results from the fact that the values of zero to two can not be used because it is not a product has dual, but clean, simple cyklotetrafosforečnan díkobaltnatý ^{c <} "° 4®i2 2 ^{P R,} respectively. simple cyklotetrafosforečnan dihořečnatý ^CM 92 ^P 4 ° 12 ^{'blocks for suspen} ° 3 ^No cyklotetrafosforečnany kobaltnatohořečnaté are blue-violet solid (according to the Co content) the density is in the ratio of Co / Mg ranging from 2.87 to 3.40 g / cm. They have a crystal structure in a monoclinic system with a spatial group C 2 / c. Its lattice parameters are in the range of 1.174 9 to 1.179 9 nm for a, 0.827 8 to 0.830 4 nm for b, 0.988 7 to 0.990 5 nm for c, 118.70 ° to 118.92 ° for angle according to Co / Mg ratio beta and elemental cell volume is in the range of 0.843 3 to 0.849 7 nm. Double cobalt-magnesium magnesium cyclotetrophosphates are chemically and thermally very stable substances. They are insoluble in water, organic solvents and dilute mineral acids, but slowly dissolve in lye solutions. It melts at high temperatures according to the Co / Mg ratio in the range of 1060 to 1160 ° C, with the latent heats of melting in the range of 130 to 305 J / g. In a completely dry atmosphere or in vacuum, they melt congruently, in an atmosphere containing at least traces of water vapor they melt non-congruently.

The present invention further provides that cobalt magnesium magnesium double cyclotetaphosphates are prepared in such a way that a melt having a temperature above 1060 ° C, preferably above 1160 ° C, containing cations of cobalt and magnesium in a Co / Mg molar ratio corresponding to (2- x) / xa and further comprising phosphate anions in an amount corresponding to a molar ratio P ₂ O ₌ / (Co + Mg) of 0.96 to 1.1, preferably of 1 to 1.005, is allowed to solidify in a completely dry atmosphere by cooling at a preferred rate less than 5 ° C / min to give the product as microcrystals. The melt temperature must be selected above the melting point or the melting point. solidification of the products, which ranged from 1060 to 1160 ° C according to the Co / Mg ratio. The ratio of cobalt and magnesium cations in the melt is selected according to the requirement for their content in the product, and the amount of magnesium cations may range from zero to two. The content of phosphate anions in the melt must correspond to a molar ratio P C> ₅ / (Co + Mg) equal to one, or values differing only slightly from one, corresponding to the c-Co ₂ _ _x Mg _x P 0 _{12 total} formula. otherwise, by-products in the form of other types of condensed phosphates would be formed and the proportion of the main product would decrease significantly. Crystallization of the product by solidification from the cooling melt should be conducted in a completely dry atmosphere (or under vacuum), since the presence of only trace amounts of water vapor would again lead to condensed phosphates with other anions and not and with ricotetaphosphate anions. In this case, it is advantageous to provide cooling of the melt at a rate of ineinil · l · · · ·. The products of the invention may optionally be further purified by curing with hydrochloric, sulfuric, nitric or phosphoric acid, since the double cyclotetrophosphates have this leaching. The preferred acid concentration for curing is 0.05 to 10% by weight, wherein the by-product separation is sufficiently effective, while the risk of attacking the main product is negligible.

The advantages of the invention are that it indicates the existence of new compounds which have not been known so far. These compounds accumulate advantageous physicochemical and application properties having simple divalent metal cyclotetaphosphates.

He did

The melt prepared by melting 100 g of higher linear cobalt phosphates and 84 g of higher linear magnesium phosphates at 1200 ° C was cooled in a dry atmosphere at a rate of 5 ° C / min. 184 g of a microcrystalline product were obtained which contained 99.2 wt. 1 of the double cobalt-magnesium magnesium cyclotetaphosphate of the formula CoMgP2O3. Blue-violet microcrystals are in a monoclinic system, spatial group C 2 / c, whose lattice parameters are a = 1,177 6 nm, b = 0,828 5 nm, c = 0,990 0 nm, beta = 118,84 ° and elementary cell volume 0,846 1 nm ³ . Their density is 3.15 g / cm ³ , the melting point is 1090 ° C and the heat of fusion is 160 J / g.

Example 2

The melt prepared by melting 150 g of higher linear cobalt phosphates and 42 y higher linear magnesium phosphates at 1120 ° C was cooled under vacuum at a rate of 20 ° C / min. 192 g of a microcrystalline product were obtained, which contained 99.4 wt. % of double cobalt-magnesium magnesium cyclotetaphosphate of formula c-CO _{3 5} Mg _Q 5 ^P 4 °] 2 ' ^Mo <3 violet microcrystals are in a monoclinic system, spatial group C 2 / c, whose lattice parameters are a = 1.178 9 nm, b = 0.829 4 nm, c = 0.989 6 nm, beta = 118.77 ° and elemental volume, 0.848 2 nm ³ . Their density is 3.26 g / cm ³ , the melting point is 1073 ° C and the heat of fusion is 137 J / g.

Example 3

The melt prepared by melting 50 g of higher linear cobalt phosphates and 126 g of higher linear magnesium phosphates at 1250 ° C was cooled in a dry atmosphere at a rate of 2 ° C / min. 176 g of a microcrystalline product containing 99.0 wt. % of double cobalt- ^{magnesium magnesium} cyclotetaphosphate of formula ^c_Co 0 (; S ^P 4 ^O 12 ' ^Blue -violet microcrystals are in a monoclinic system, spatial group C 2 / c, whose lattice parameters are a = 1,176 9 nm, b = 0,828 9 nm, c = 0,989 7 nm, beta = 118.91 ° and the volume of the elemental cell is 0.845 3 nm ^3. Their density is 3.00 g / cm ³ , the melting point is 116 ° C and the heat of fusion is 204 J / g.

Claims (1)

SUBJECT OF THE INVENTION 1. Double cobalt magnesium magnesium cyclotetrophosphates of the formula ^σ £ ^ο 2-χ ^Μ 9χ ^Ρ 4 ^ο ι2 ^{de de} x is in the range from near zero to near two. ? . of mouth, ili ρ ί I pi. t υ y ρ / "I v <,) ι · 1ι i y I". It is characterized by the fact that I <v v in 1 ep I,, 1 above I 060 ° C, preferably above 1160 ° C containing cobalt and magnesium cations in a Co / Mg molar ratio corresponding to (2-x, / x) and further comprising phosphate anions in an amount corresponding to a molar ratio of P 10 O 4 / (Co + Mg) of 0.97 to 1.1, preferably equal to 1 to 1.005 are allowed to solidify in a completely dry atmosphere by cooling, preferably at a rate of less than 5 ° C / min, to produce double cobalt-magnesium magnesium microcrystalline cyclic character and the products optionally purified by curing with hydrochloric, sulfuric, nitric or phosphoric acid, preferably , 05-10%.