CLUSTERS OF WATER IN THE COMPOSITION OF ANTIFREEZES

Aleksandr Miroshnikov,Aleksey Gushchin,Nadegda Ushakova,Zoya Esina

doi:10.12737/11468

Abstract

Antifreezes based on water eutectics are widely spread in engineering and by crio-preservation of biological objects as well. Salts of inorganic and organic acids, alcohols, glycols, glycol ethers, glycerin, acids, bases, amino- acids, and other chemical compounds are suitable here as supplementary means. Part of these compounds is capable to take part in the formation of H-bonds with water molecules, the others do not form H-bonds (CaCl2), but they are united into crystal-hydrates of CaCl2 · 6 Н2О type. In this case H-bond of water molecules can become the bond of intermolecular-cluster type. It is assumed that basic structural components of liquid water are cyclic penta- (H2O)5 and hexamers (H2O6), built with the participation of the long hydrogen bond and capable of producing the crown effect. Cyclic water clusters - short-range order of water in terms of cavity size and the number of oxygen atoms correspond to crown ethers: 15-crown-5 and 18-crown-6, sodium and calcium ions being absorbed into them. Energy estimation of water and ice (snow) interaction with the components of antifreezes: ethylene- and diethylene glycols, ethylene glycol ethers, hydrogen chloride and ammonia is made. Possibility of solution formation with low freezing temperatures is shown. The analysis of the eutectics and diagrams of water antifreeze fusion based on the salts, alcohols, ethylene glycol, ethylene glycol ethers, hydrogen chloride and ammonia by comparison with an ideal solution of water concerning cryoscopic constant is carried out. It is established that the coefficient K in the equation of linear melting curve y = К·x + в for effective antifreezes, in terms of freezing temperature, exceeds the cryoscopic constant of water, that testifies to the destruction of long-range order of water. Penta- and hexamers of water responsible for short-range order of water pass into the eutectics as monomers or oligomers with the degree of cross linking equal to 2-4. To create effective antifreeze it is important to avoid the destruction of cyclic water clusters. It is desirable, as in the case with ethylene, to have the second component of water antifreeze in a cyclic form too. There is an analogy with naphthenic (cyclic) hydrocarbons of oil, which provide mobility of the condensed state. Promising are antifreezes based on mixtures of inorganic and organic compounds.

Highlights

Solutions with low freezing temperature based on water are known in nature and are widely used in the technology of food production
Small (b = 6–46) water clusters should essentially be in the eutectic and the second eutectic component cluster join the structure of water clusters or voids between them
Analysis of eutectics and diagrams of aqueous antifreeze fusion, based on salts of inorganic and organic acids, alcohols, ethylene glycol and its ethers, consisted in the comparison with an ideal water solution on cryoscopic constant. It made it possible to reveal cyclic water clusters of (H2O)5 and (H2O)6, which pass into the eutectics as monomers or oligomers with the degree of cross linking 2–4

Summary

Introduction

Solutions with low freezing temperature based on water (antifreezes) are known in nature and are widely used in the technology of food production. The antifreeze composition comprises salts of inorganic and organic acids, alcohols, glycols, glycerin, acids and bases, amino acids and other compounds. Interaction force in the solution is evaluated by the osmotic pressure P, which depends on the concentration of the solute [1]. Diluted (thin) solutions (10–6 - 10–2 mole / dm3), in which osmotic pressure does not depend on the nature of the solvent and solute and is determined only by the number of interacting particles. The osmotic properties of solutions include lowering the freezing point of the solvent (water) caused by the additive

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