SU1740315A1 - Method for sodium methaphosphate (gram salt) preparation - Google Patents

Abstract

The invention relates to methods for producing phosphorus compounds that can be used in optical glassmaking. Sodium acetate is taken as the sodium-containing compound, dry metaphosphoric acid is used as the phosphorus-containing compound in a weight ratio of (1.01-1 04) -1. 1 ill., 1 tab.

Description

The invention relates to methods for producing phosphorus compounds, in particular vitreous sodium metaphosphate, which is used primarily in optical glassmaking.

The closest to the present invention is a method for the synthesis of vitreous sodium metaphosphate (Graham salt) by melting sodium dihydrogenphosphate, MANPHOS 2HaO, followed by quenching of the melt. Melting of sodium dihydrogen phosphate is carried out at a temperature slightly below 1000 ° C. Then the melt is poured onto a cooling plate made of copper or another metal with good thermal conductivity and cooled with water.

The disadvantages of this method are the high temperature of the process of melting sodium dihydrogen phosphate (about 1000 ° C), the use of precious platinum crucibles, contamination of the final product as a result of the corrosion of the metals used (cooling plates) and the complexity of instrumentation. Purity of products 97 - 99% Remaining 1 - 3% - impurities.

The purpose of the invention is to obtain the desired product of high purity.

The goal is achieved by taking sodium acetate as the sodium-containing compound, metaphosphoric acid as the phosphorus-containing compound with the mass ratio of sodium acetate to metaphosphoric acid (1.01 - 1.04) 1 -246-76 (70) and NROZ brand ch GOST 841-64. The process of interaction and melting is carried out in a muffle furnace using a porcelain cup at 200 - 800 ° C, with step heating at 200 ° C for 120 minutes, then after 400 ° C - 120 minutes, at 600 ° C - 60 minutes at 700 ° C - 60 min., At 800 ° C - 20 min. The resulting liquid alloy is poured onto ice. After quenching and cooling, glassy sodium metaphosphate is obtained (Gram's salt). The yield of the product is 81.14 - 84 66%. The target product contains almost no impurities. Purity 100%

Found% Na20 30.34 - 30 38 P205 69 62 - 69.66

IAROS (Graham's salt);

Calculated,% NaaO 30.39; P20s 69.61

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The resulting sodium metaphosphate was studied by IR spectroscopy. IR absorption spectra and absorption maxima in the region,. 475; 525; 730; 770; 865; 990; 1094; 1150; 1280, which corresponds to the glassy metaphosphate of sodium (Graham's salt).

The drawing shows the IR spectra of vitreous sodium metaphosphate.

IR absorption spectra are identical to the spectrum of the Graham salt — NaPOs.

Example 1.82 g of sodium acetate and 80 g of metaphosphoric acid are placed in a porcelain dish, mixed and heated in a muffle oven at 200 ° C for 120 minutes, at 400 ° C - 120 minutes, at 600 ° C - 60 minutes, at 700 ° C - 60 min, at 800 ° С -20 min. The resulting liquid melt is poured onto ice, after quenching and cooling, a vitreous product is obtained.

The yield of sodium metaphosphate (Graham salt) is 83.53%. Product purity 100% IR absorption spectra are identical to Graham's salt (a).

Found,%; Na20 30.34; PaOs 69.66.

#Rose

Calculated% Na2030.39-P20s 69.61.

Example 2. 81 g of sodium acetate and 80 g of metaphosphoric acid are placed in a porcelain dish, mixed and heated in a muffle oven at 200 ° C for 120 minutes, at 400 ° C - 120 minutes, at 600 ° C - 60 minutes, at 700 ° C-60min, at 800 ° C-20min. The resulting liquid melt is poured onto ice, after quenching and cooling, a vitreous product is obtained.

The yield of sodium metaphosphate (Graham salt) is 84.66%. The purity of the product is 100%. IR absorption spectra are identical to Graham's (b) salt spectra.

Found,%: Na20 30.37; P20s 69.63.

#Rose

Calculated,%: Na20 30.39; P2U5 69.61.

Example 3. 83 g of sodium acetate and 80 g of metaphosphoric acid are placed and heated in a muffle oven at 200 ° C for

120 min, at 400 ° C - 120 min, at 600 ° C - 60 min, at 700 ° C - 60 min, at 800 ° C - 20 min. The resulting liquid melt is poured onto ice, after quenching and cooling, a vitreous product is obtained.

The yield of sodium metaphosphate (Graham salt) is 81.14%. The purity of the product is 100%. IR absorption spectra are identical to Graham's salt (c).

Found,%: № 20 30,38; P20s 69.62.

#Rose

Calculated,%: NaaO 30.39; P2U5 69.61.

Examples of a specific implementation of the method and a number of additional examples are given in the table.

As can be seen from the table (examples 1–3), when the process is carried out with a ratio of sodium acetate and metaphosphoric acid less than (1.01: 1), the resulting product contains 0.5–4.5% P20s.

When carrying out the process with a ratio of sodium acetate and metaphosphoric acid more than (1, C4 1), the resulting product contains 0.7-5% C (examples 7-10 in the table).

When carrying out the process below 800 ° C, the reaction mixture does not convert to liquid melt.

Thus, the proposed method allows to obtain vitreous sodium metaphosphate (Graham salt) and completely eliminate impurities. The purity of the sodium metaphosphate obtained is 100% versus 97 - 99% (in the prototype).

Claims (1)

Invention Formula The method of producing sodium metaphosphate (Graham salt) by heat treatment of phosphorus and sodium-containing compounds under step heating, with the fact that, in order to obtain the target product of high purity, sodium acetate is used as the sodium compound, the phosphorus-containing compound is used Ny acid in a mass ratio (KOI - 1.04); 1. The degree of purity of pies, the impurities in the product, 400 i I 11 i) i i i I i l i I i I, g. i i i. I i i i i 600 n 90 ° i30Q i700 2000 Z2DO 2b °° 00 ° TOOfj. No PjOj E5,5 Naro, but f four  00 ° fj No