(69% of theor.) m.p. 1570° (cryoscopy). Softening temperature 115–127°C.

In the IR spectrum of the polymer (IKS-14a, vaseline oil), absorption bands in the region 3400–3600 cm\(^{-1}\), characteristic of secondary amino groups and oxy groups, are absent; absorption bands appear in the region 1625 cm\(^{-1}\), 995 cm\(^{-1}\), corresponding to absorption by the terminal vinyl group, which confirms the structure of poly-N-(4-vinyloxy)-vinylideneamine.

The polymer is a dark-cherry-colored powder, readily soluble in ketones, dimethylformamide, and aqueous alkali solutions.

References

1. W. H. Watanabe. J. Amer. Chem. Soc., 79, 2833, (1957).
2. M. F. Shostakovskii. ZhOKh, 31, 1237, (1961).
3. R. P. Lastovskii, Yu. M. Vanshtein. Technical Analysis in the Manufacture of Intermediates and Dyes. Moscow, Goskhimizdat, 1958, p. 173.
4. S. P. Mushtakova, N. S. Frunkina, L. A. Gribov. ZhAKh, 26, 430, (1971).
5. R. Adelman. J. Amer. Chem. Soc., 75, 2678, (1953).

Silicate Formation during the Melting of Glass of Diopside Composition

P. G. Usov, V. I. Vereshchagin, E. P. Tsymbaluk

Recently, intensive work has been carried out in the field of obtaining glass-ceramics with good dielectric characteristics. The most promising in this respect are glass-ceramics with a diopside-like crystalline phase. Studies by a number of authors have shown that such glass-ceramics possess not only good mechanical and chemical characteristics /1/, but also fairly good dielectric properties /2/. In our previously conducted work /3/ it was shown that crystallization of diopside compositions of glass proceeds readily and without the formation of by-products only on the basis of the natural mineral tremolite.

Tremolite, \(Ca_2Mg_5[Si_8O_{22}](OH)_2\), is a typical representative of the amphibole minerals, whose structure is characterized by infinite ribbons \([Si_4O_{11}]_\infty\), consisting of doubled pyroxene chains \([SiO_3]_\infty\). The synthesis of diopside from tremolite proceeds

melilite occurs readily as a result of the similarity of the diopside structure to the tremolite structure (for diopside \(a,b,c\)—\(9.71; 8.89; 5.24\ \text{Å}; \beta = 105^\circ 50'\), for tremolite, respectively, \(9.84; 18.05; 5.28\ \text{Å}; \beta = 104^\circ 42'\)).

The discovery of large tremolite deposits at the Al’guiskii deposit (Kemerovo Oblast) eliminates the shortage of such raw material for obtaining diopside materials. An important feature of this tremolite is its high calcite content (20–25%), which greatly reduces the additional introduction of calcium carbonate for diopside formation. The low content of iron oxides (0.3–0.4%) and the absence of oxides of transition metals make it possible to obtain materials with good dielectric characteristics. The crystallization process of glass is strongly influenced not only by the heat-treatment regime, but also by the thermal history of glass production. Therefore, establishing the genetic relationship between silicate-formation processes taking place in the batch, the preservation of molecular groupings of diopside in the melt and glass, and its crystallization capacity is of great scientific and practical interest. Similar work was carried out by L. A. Kupina et al. for batches based on technical products /2/.

In our work, the task was set to trace the reactions of silicate formation in batches both on the basis of tremolite and on the basis of pure oxides.

The calculation of the batch composition was based on obtaining a material with 75% crystalline phase of diopside composition and 25% glass phase of composition \(\mathrm{CaO}\)—11.0; \(\mathrm{Al_2O_3}\)—14.0; \(\mathrm{SiO_2}\)—75.0 wt.%. The chemical and component composition of the investigated batches is given in Tables 1 and 2.

Table 1

Specified chemical composition of the batch (wt.%)

Table 2

Component composition of batches (wt. %)

As the main components, tremolite from the Altai deposit, Chasov-Yar clay, calcium carbonate, Tashlin sand, and oxides of reagent-grade purity (“ch.d.a.”) were used (Table 3).

Table 3

Chemical composition of batch components
(wt. %)

The tremolite-based batch was ground and mixed by the wet method in a ball mill until it passed through sieve No. 0060 (10,000 openings/cm$^2$).

The batch based on pure oxides was prepared by thorough—

of mixing the components in a ball mill by the dry method. The batches obtained were briquetted and heated at a rate of 300–500 deg/hour to a temperature of 1200–1300°C, with holding at the final temperature for 1 hour.

As X-ray phase analysis showed, the processes of silicate formation begin in the temperature range 500–600°C (decomposition of calcium carbonate) and end at temperatures of 1100–1200°C.

For the tremolite-based batch, the process of diopside formation occurs upon decomposition of tremolite already from 900°C (the maxima 1.438; 1.500; 2.70 Å disappear and 3.00; 2.52; 1.62 appear). At the same time, the formation of other decomposition products, apart from diopside, is not observed. At higher temperatures (from 1100°C), the process of formation of wollastonite \((CaSiO_3)\) is observed as a result of the binding of free calcium oxide with silica. Thermogravimetric and differential-thermal analyses confirm the scheme of silicate formation in the tremolite-based batch. The maxima of endothermic effects on the DTA curve of the tremolite-based batch correspond to 865°C for calcite and 1030°C for tremolite. They are shifted toward higher temperatures owing to the continuity of the heat treatment (10–15 deg/min). The total weight losses on the TG curve for this batch amount to 11.1%, which corresponds to the theoretically possible losses (11.7%).

In the batch based on pure oxides, the reactions of diopside formation do not proceed even at temperatures up to 1250°C, which strongly affects the crystallization product of such a glass. During crystallization of glass obtained on the basis of tremolite, the principal crystalline form is diopside; during crystallization of glass from oxides, along with diopside, silica and magnesium metasilicate are present. The melting of the glass is also facilitated in tremolite-based batches. In melting glass from pure oxides at a temperature of 1450°C, holding for 3 hours does not lead to complete melting.

In general, the picture of silicate-formation reactions in the tremolite-based batch may be represented as follows.

I. At low temperatures, decomposition of the compo-

components of the batch into oxides:

monothermite:

\[ \mathrm{Al_2O_3 \cdot 4SiO_2 \cdot H_2O} \ \xrightarrow{500^\circ\text{--}600^\circ \mathrm{C}}\ \mathrm{Al_2O_3 \cdot 2SiO_2 + 2SiO_2 + H_2O}\uparrow \]

calcite:

\[ \mathrm{CaCO_3} \ \xrightarrow{500^\circ\text{--}800^\circ \mathrm{C}}\ \mathrm{CaO + CO_2}\uparrow \]

1. At higher temperatures, processes of diopside formation take place.

At first, an intermediate-composition pyroxene is formed, corresponding to the structure of diopside:

\[ \mathrm{2CaO \cdot 5MgO \cdot 8SiO_2 \cdot H_2O} \ \xrightarrow{900^\circ\text{--}1000^\circ \mathrm{C}}\ \mathrm{2CaO \cdot 5MgO \cdot 7SiO_2 + SiO_2 + H_2O}\uparrow \]

Then, through the interaction of this primary product of tremolite decomposition with free calcium oxide and silica, diopside of stoichiometric composition is formed:

\[ \mathrm{2CaO \cdot 5MgO \cdot 7SiO_2 + 3CaO + 3SiO_2} \ \xrightarrow{1000^\circ\text{--}1100^\circ \mathrm{C}}\ \mathrm{5CaMgSi_2O_6} \]

In total the reaction appears as follows:

\[ \mathrm{2CaO \cdot 5MgO \cdot 8SiO_2 \cdot H_2O + 3CaO + 3SiO_2} \ \xrightarrow{900^\circ\text{--}1100^\circ \mathrm{C}}\ \mathrm{5CaMgSi_2O_6 + H_2O}\uparrow \]

Beginning at temperatures of \(1000^\circ\mathrm{C}\), in parallel with the reactions described above, calcium oxide interacts with silica with the formation of wollastonite:

\[ \mathrm{CaO + SiO_2} \ \xrightarrow{1000^\circ\text{--}1100^\circ \mathrm{C}}\ \mathrm{CaSiO_3} \]

In turn, at temperatures above \(1200^\circ\mathrm{C}\), wollastonite begins to interact with the remaining primary product of tremolite decomposition:

\[ \mathrm{2CaO \cdot 5MgO \cdot 7SiO_2 + 3CaSiO_3} \ \xrightarrow{1200^\circ\text{--}1300^\circ \mathrm{C}}\ \mathrm{5CaMgSi_2O_6} \]

With this reaction, at temperatures of about \(1300^\circ\mathrm{C}\), the process of formation of diopside of stoichiometric composition is completed.

Conclusions

1. In a batch based on tremolite, the reactions of diopside formation begin at \(900^\circ\mathrm{C}\). Diopside of stoichiometric composition is finally formed at temperatures of \(1300^\circ\mathrm{C}\). In a batch based on pure oxides, at a temperature of \(1300^\circ\mathrm{C}\), there are observed

only traces of diopside.

1. The formation of diopside at the stages of solid-phase reactions in a batch based on tremolite promotes rapid glass formation and clarification of the melt. Glass based on oxides at melting temperatures (1425–1450°C) is not completely clarified.

2. The formation of diopside at the stages of silicate formation promotes an increase in the crystallization capacity of the glass. In this case the principal crystalline phase is diopside of stoichiometric composition.

Literature

1. L. A. Zhunina, Z. I. Govorushko, V. D. Mazurenko. Change in the structure and properties of glasses of pyroxene compositions as a function of heat-treatment conditions. In the collection Glass, Glass-Ceramics and Silicate Materials. Issue I, “Vysshaya shkola,” Minsk, 1970.

2. L. A. Zhunina. Study and synthesis of pyroxene glass-ceramics. In the collection Glass, Glass-Ceramics and Silicate Materials. Issue I, “Vysshaya shkola,” Minsk, 1970.

3. V. I. Vereshchagin, E. P. Tsymbalok. Preparation and study of glass-ceramics based on tremolite with a diopside and crystalline phase. Abstracts of reports at the XVI Regional Scientific-Technical Conference, Novosibirsk, 1973.

CORRELATION ANALYSIS OF THE RELATIONSHIPS BETWEEN THE YIELD OF LIGHT PETROLEUM FRACTIONS AND ITS SPECIFIC GRAVITY

T. G. Blagopoluchnaya, N. M. Smolyanikova, A. F. Fedorov

Many years of practice have established a number of indices of petroleum and petroleum products that characterize their properties with sufficient completeness. Such characteristics include: specific gravity, fractional composition, viscosity, pour point, coke content, flash point /1/.

Specific gravity, belonging to the number of the most widespread—