3. Surfactants - Fire Extinguishants.

With the advent of new materials made of synthetic organic compounds the problems of their inflammation protection arose. The ordinary fire extinguishants are not effective for them. Moreover the worked out fire extinguishants based on perfluoroalkylchlorides and perfluoroalkylbromides, appeared to be ozone unsafe and their production is stopped. Foam is widely used for fire extinguishing at industrials plants, oil storages, transport etc. Foam is a dispersion, consisting of gas bubbles, surrounded by liquid films, and it is characterized by thermodynamic instability regarding the aggregate one.

 Aerosols on the base of organic compounds also possess a number of disadvantages. Fire extinguishants on the base of fluorine-containing compounds have more potential. They can be divided into several groups. The main among them are:

1. Extinguishants, consisting of ozone safe chladones (freons),

2. Foam former, intended to obtain air-mechanical foam for fire extinguishing.

In spite their high cost the compounds on the base of fluorine-containing compounds have rather fast proved their effectiveness and they are used both for common fire extinguishing, fire extinguishing of reservoirs with petroleum and other organic solvents and end use, in particular, of cars, movable installations and places with mass people stay.

Earlier, freons, mainly bromine-containing ones, had found their application in different field of techniques. However, they are ozone destructive and according to Montreal Protocol were prohibited for operation. Russia follows this protocol and production of such chladones (chladones 13B1, 12B1, 114B2 and other) now is stopped in Russia.

Compounds close to them by physical properties and reproducing their high operational characteristics are considered as an alternative for bromo-chladones.

On the basis of defined in laboratory conditions fire extinguishing concentrations of ozone safe compounds and opportunity of their production as most promising ones for application chladones 125 and 227ea were chosen. At that the most preferred is chladone 125 [138]. The action of present chladones lies in formation of aerosol cloud, which covers the extinguished object, that prevents air oxygen to pass into combustion zone or blocks its inflow. Because of this the combustion is ended.

The practical interest in wide group of different purposes' fluorine-containing surfactants is constantly increasing, that causes search for optimal, available for commercial production compounds. Fluorine-containing surfactants of cationic, anionic and nonionic types with necessary physical - chemical and colloid-chemical properties are created.

Foams made out of fluoroorganic surfactants are effective, because solution, isolating from foam, gives film on the surface of combustible liquid, this film prevents foam from destruction. They are chemically and thermally stable, biologically resistant and their surface stability is high. High fire extinguishing capability of film-forming compounds on the base of fluorine compounds allows to feed foam under to the layer of combustible and also spraying from over it, that facilitates the fire extinguishing process. At layer-by-layer method of fire-extinguishing the coming to surface foam can bypass constructions sunken in reservoir and spread all over the surface later. After fire extinguishing and ending of feeding all over the combustible summary surface the stable layer with the thickness up to 5 cm is formed, which prevents it from re-inflammation.  Such foam formers on the base of fluorine-containing surfactants found their application for fire extinguishing of both polar and non-polar liquids (benzine, acetone, kerosene etc.) and also for A and B class fire extinguishing. 

 High reliability of fire-extinguishing, particularly the high resistance to re-inflammation of laying under the foam layer liquid already extinguished is also referred to the advantages of such materials. Foam formers on the fluororganic compounds are hard- to -inflame liquids, and their work solutions are fire-safe and explosion-proof. In industry foar formers are produced by solution of fluoroorganic concentrate in water.  Mainly, the following fluorine materials: PO-6 FP, Foretol, "Universal" find their application. The intensity of frother feed at fire extinguishing of standard fuel (n-hexane) using foam of medium multiplicity, kg/m²s is : 0.05, 0.08, 0.08. Work concentration % vol. 6, 10, 10 respectively. They are homogeneous coloured liquids without sediment and fibering.

Technical requirements for complete product (work solution)

Purpose of use/designation:

1. PO-6 FP- for fire extinguishing of hydrocarbons using air-mechanical foam with fresh water
   
2. Foretol - for fire extinguishing of burning polar liquids (alcohols, organic acids etc/) using air-mechanical foam with fresh water
   

In Russia the production of such fire extinguishing facilities is organized as test version (layer-by-layer frother PO-6 FP (TU 241279-130-05807960-97)) at JSV Halogen  (Perm city). Foam former named “Easy water” of 3M company (USA) is analogue of PO-6 FP. Foam former PO-6 FP is a biologically degradable product, the rate of biodegradation > 80%. Application limitation – can't be used for fires of B2, C, D classes.

3.4. Compositions for Surface Treatment of Products, Antirust Coatings.

The need for high-temperature lubricants, which at treatment of moving components increase the operation life of mechanisms, is great, because their friction coefficient is low. Along with that they can be used as lubricants of both rolling mills for steel and for other metals. Other field of application is for oil equipment and oil pipelines, because such lubricants are not washed out by organic compounds compare to mineral oils.

A group of chemicals for treatment of waterproof cotton fabric with high consumer properties was created on the base of perfluorinated carboxylic acids [139]. Fluorocarboxylic chemical AFS (Hechst, Germany) gives the best water-repellent ability to fabric. Fabric trimming using this chemical results in improving of stability of shape, moisture resistance, fabric strengh, light resistance etc.

Fluorinated surfactants found their application in technics as modifiers of solid surfaces for giving antiadhesive, antofriction, antiscruff, antiwear, corrosion preventing properties to them. [140].

Fluorine-silicon organic compounds on the base of perfluorocarboxylic acids' amides are used for treatment of monuments, they create a protective layer on their surface, blocking moisture, acid admixtures and industrial pollution penetration into pores of buhr/limestone. [141]. These materials are obtained according to the following scheme:

Conclusion

The material, we had discussed in this review, shows a growing researchers' interest to development of new introduction methods of perfluorinated fragments into molecules of organic compounds and methods of ordinary substituents' transforming into complicated functional groups. Noticeable success, reached in creation of new perfluoroalkylating agents show, that in a few cases they can be an alternative for classical and well-known reagents. 

Thus, perfluoroalkyliodides are widely used to carry out perfluoroalkylating reactions in the presence of initiators and catalysts. Such processes as radical perfluoroalkylating, formation of perfluoroalkylsulfine and perfluorocarboxylic acids, poly-fluorinated alhydes, electrochemical synthesis of perfluoroalkyl derivatives have obvious advantages, they are rather simple and can be commercially realized. We can hope, that later new reactions and transformations resulting in fluorine-containg compounds' formation, would be found.

In this review there was made an attempt to demonstrate new approaches and synthetic opportunities of new reagents, to show tendencies and main directions of researches in the field of perfluoroorganic compounds, containg different molecular skeletons and functional groups. The discussion over material appeared to be very useful, because it often allowed to see the problem from the untraditional for chemists point of view, to find some original solutions, based on use of new approaches to generation of perfluoroalkyl radicals, their involving into reactions with different compounds. As reaction of perfluoroalkyliodides with alkenes is one of the most important fundamental reactions not only in fluororganic compounds' chemistry but also in organic chemistry in general, it's obvious that more delicate work is necessary to solve these puzzling problems.

There is no doubt, that implementation of discussed above ideas and processes, passing according to the scheme of one-electrone transfer is of interest not only of chemists-fluororganics, but also of specialists in the field of organic synthesis, of scientists developing fundamentally new influiencing methods on organic compounds molecules with the purpose of creating new technologies. At that you can see, that in a number of cases perfluoroorganic compounds are convenient and sometimes unique models both for creation of new effective reagents and for setting and solving a number of fundamental problems of theoretical organic chemistry. Thereby the role of perfluorine-containing organic materials is increasing non-stop, though only a small number of perfluoroalkylating agents, which could be commercially used, is known so far. However, soon you can expect a great progress in this field. Thus, the effective working out of methods transforming organic compounds into valueable fluorine-containing products will promote the progress of organic synthesis as a whole.

References