Industrial fluorine compounds

Article abstract of DOI:10.1134/S1070427209060408

Technological research in the area of the industrial fluorine-containing compounds: ozone safe fluorocarbons (freons), fluoro-olefins, compounds with the functional groups, thermoresistant liquids, oils, lubricants, fluorine surfactants and other.

Full text of DOI:10.1134/S1070427209060408

ISSN 1070-4272, Russian Journal of Applied Chemistry, 2009, Vol. 82, No. 6, pp. 1133−1141. © Pleiades Publishing, Ltd., 2009.
Original Russian Text © V.G. Barabanov, B.N. Maksimov, 2009, published in Khimicheskaya Promyshlennost’, 2009, Vol. 86, No. 2, pp. 55−64.
TECHNOLOGY OF ORGANIC
AND INORGANIC CHEMISTRY
Industrial Fluorine Compounds
V. G. Barabanov and B. N. Maksimov
Russian Scientific Center “Applied Chemistry”, St. Petersburg, Russia
Received December 4, 2008
Abstract—-Technological research in the area of the industrial fluorine-containing compounds: ozone safe
fluorocarbons (freons), fluoro-olefins, compounds with the functional groups, thermoresistant liquids, oils,
lubricants, fluorine surfactants and other.
DOI: 10.1134/S1070427209060408
Protocol obligated the parties regarding the limitation of
consumption, production and import/export of ODS.
OZONE SAFE COMPOUNDS
Chlorofluorocarbons and bromofluorocarbons (freons
and halons) as the compounds, which possess a number
of unique properties: chemical inertness, nontoxicity,
explosive-fire safety, were widely used in the technology
as the aerosol propellants, the refrigerants, the frothing
agents for plastics, solvents, highly effective fire
extinguishers and others. However, discovered in 1980th
a destructive action of some chlorine- and bromine-
containing compounds on the ozone layer attracted
attention to the large group of industrial freons, which
contain in their composition chlorine and bromine, as to
the potentially dangerous compounds. The contemporary
evaluations of the relative role of the anthropogenic and
natural factors of the destruction of ozone layer showed
that above Western Europe the relative contribution of
anthropogenic factors is ~75%, above the East coast of
the USA, 60%, above Japan, Baikal and the Far East,
50%. The Viennese convention about the protection of
ozone layer, accepted in 1985 was the first international
document, which foresees measures for the protection
of ozone layer. The states signed convention, accepted
obligations regarding collaboration in the area of control
and averting activity potentially threatening ozone
layer of stratosphere. In September 1987 was accepted
Montreal Protocol (MP) on the substances, which destroy
ozone layer. In the application to MP was published a list
of ozone destroying substances (ODS), that be subject to
regulation by all country-parties of MP. To the list were
included the chlorofluorocarbons, bromofluorocarbons
(halons) and some chlorohydrocarbons. The Montreal
The Soviet Union was one of the most important in the
world producers of ODS: in 1987 it held ~15% of world
volume of ODS productions (~200 thousand ton per year),
simultaneously the Soviet Union was one of the largest
exporter of ODS, supplying not only all republics of the
former USSR, but also many countries of Europe and
Asia. Producers of ODS were six large chemical plants in
the Russian Federation. The users of freon in the Russian
Federation were practically all branches of industry [1−3].
Structure of the application of freon in 1990 appeared as
follows: production, repair and service of everyday and
commercial industrial refrigeratoring equipment were
27%; the production of aerosols in containers, 45%; the
production of foam producing agents, 11%; the use of
freon as the solvents, 14%; the production of the means
of fire extinguishing, 2%; other, 1%.
The Russian Federation, being the lawful successor of
the USSR, which ratified in 1988 the Montreal Protocol
on the substances, which destroy ozone layer, completely
accepted the obligations on this protocol to cancel
production and consumption of ODS.
Russian Scientific Center “Applied Chemistry”
together with the number of the institutes in the country
is executed large volume of the works on the transfer
of industry to produce the new class of the chemical
compounds instead of forbidden ODS. As a result of the
conducted investigations is proposed the nomenclature of
new freons: hydrofluorihydrocarbons 134a (CF3CFH2),
152a (CF2HCH3), 125 (CF3CF2H), 32 (CH2F2) and other.
1133

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BARABANOV, MAKSIMOV
Company “Caustic” (Volgograd), Joint Stock Company
“Khimprom”(Volgograd), JointStockCompany“Caustic”
(Sterlitamak), Joint Stock Company “Usolekhimprom”
(Usole Siberian) and other.
A basic difference in the ozone safe compounds from
ODS is absence in their molecules of the atoms of chlorine
and bromine, which can participate in “chlorine” and
“bromine” cycles of the ozone decomposition. Besides
the zero value of the ozone destroying (ODS) and the
permissible value of the potential (ODP) and the value
of the potential of the global warming of climate (GWP),
the main guide for selection of substitutes ODS is the
proximity of physicochemical and performance properties
to the analogous characteristics of replaced ODS. The
basic nomenclature of ozone safe compounds, accepted
for the development and the introduction in the industrial
production in the Russian Federation, is represented in
Table 1.
The special features of liquid-phase catalytic hydro-
fluorination are well seen on the example of the synthesis
of difluoromethane (Freon 32) [4]. The process of
synthesis proceeds according to Scheme 1.
Scheme 1.
k0
SbCl5 +HF → SbClnF5−n + HCl
At the development of the technologies of ozone
safe fluorocarbons, depending on their structure and
taking into account the existing production capacities of
replaced freons 11, 12, 113 at the plants of the country
are used in essence two methods of their manufacturing:
liquid-phase fluorination by waterless hydrogen fluoride
of organochlorine compounds (Freons 152a, 32, 143a
and other) and the gas-phase catalytic fluorination of
chlororganic compounds by waterless hydrogen fluoride
(Freons of 134a, 125 and other).
k1
CH2Cl2 + SbClnF5−n → CH2ClF + SbCln+1F4−n + HCl
HF
k2
CH2ClF + SbClnF5−n → CH2F2 + SbCln+1F4−n + HCl
HF
The kinetics of the fluorination of methylene chloride
is described by the following equations [5]:
The basic raw materials for the production of ozone
safe Freons including trichloroethylene, perchlorethylene,
vinylidene chloride, vinyl chloride and chloromethanes
are produced in the enterprises of Russia: Joint Stock
−rCH2Cl2 = 2.2 × 105/{exp(−5.8 × 107/RT)CCH Cl Ck},
2
2
rCH2F2 = 8.3 × 105/{exp(−6.2 × 10/RT)CCH ClFCk},
2
Table 1. Principal characteristics of hydrofluorocarbon (ozone safe Freons)
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INDUSTRIAL FLUORINE COMPOUNDS
1135
where CCH Cl , CCH ClF, Ck are the concentrations of
dichloromethane, chlorofluoromethane and catalyst,
respectively.
(of the organic part of the products of synthesis). For
conducting the process is used a chromomagnesium
fluoride catalyst [8], prepared by impregnation of the
powder of magnesium fluoride with the solution of
chromium chloride followed by stirring, molding, drying
and working up by hydrogen fluoride for the transfer of
CrCl3 into the fluoride CrF3 [9, 10].
2
2
2
On the basis of the kinetic data is perfomed calculation
of the reactor for the synthesis of Freon 32 1000 ton per
year, and the flow chart of the synthesis of Freon 32,
which is standard for the liquid-phase synthesis of
ozone safe Freons, is developed. Synthesis is carried
out at a temperature of 95−105°C and pressure 1.5−2.0
MPa. According to analogous scheme is carried out
the synthesis of Freon 152a from vinyl chloride and
hydrogen fluoride at the temperature of 90°C and
pressure 0.6−0.8 MPa in the presence of catalyst tin
tetrachloride [6], and also the synthesis of Freon 245fa
from pentachloropropane and hydrogen fluoride in the
presence of SbCl5 at a temperature of 100−120°C and
pressure 1.6−1.8 MPa [7].
A study of the mechanism of the action of catalyst in
this process showed that the catalyst bears a function of
the carrier of fluorine and chlorine atoms [11, 12]. The
process of the hydrofluorination of fluorinechloroethanes
can be considered proceeding according to Scheme 3.
Scheme 3.
However, the liquid-phase method of hydrofluorination
has certain limitations:
− the replacement of chlorine atom by the atom of
fluorine in the groups, CH2C1 and =CHCl proceeds
difficultly,
where chromium fluoride replaces chlorine by fluorine in
the fluorinechloroethanes, changing its own composition
to CrF2Cl, and then hydrogen fluoride replaces chlorine
by fluorine in the active part of the catalyst with the
formation of hydrogen chloride and CrF3.
− at the hydrofluorination the catalyst SbClnF5− n can
behave as a chlorinating agent with the formation of ozone
decomposing chlorofluoroalkanes.
Therefore for obtaining the hydrofluohydrocarbons
with the high content of fluorine in the molecule
(CF3CFH2, CF3CF2H) is used the method of gas-phase
catalytic hydrofluorination.
Besides the basic processes of hydrofluorination,
in the presence of this catalyst occur also the reactions
of dehydrofluorination, dehydrochlorination and
disproportionation (Scheme 4).
Features of gas-phase catalytic hydrofluorination are
well seen from the example of the synthesis of 1,1,1,2-
tetrafluoroethane (Freon of 134a) from trichloroethylene
and hydrogen fluoride. The process of synthesis proceeds
into two stages (Scheme 2).
Scheme 4.
CF3−CH2Cl ' CF2=CHCl + HF
CFCl2−CH2Cl ' CFCl=CHCl + HCl
2CF3−CH2Cl ' CF3−CH2F + CH2−CHCl2
Scheme 2.
C2HCl3 +3HF → C2H2ClF3 +2HCl + 93 kJ mol–1 (1)
C2H2ClF3 +HF → C2H2F4 + HCl– – 18 kJ mol–1 (2)
Theformedunsaturatedfluorine-containingcompounds
(in particular, CF2=CHCl that forms azeotrope with
1,1,1,2-tetrafluoroethane) complicate further isolation of
the targeted compound from the reaction mixture.
As follows from the experimental data and the
thermodynamic calculation of stage (1), the content
of Freon of 133a in the organic part of the products of
synthesis can reach 90−98%.
The stage (2) is reversible. Depending on the
conditions, the content of Freon of 134a in the organic
part of the products of synthesis can be 10−40 vol %
The mechanism of the reaction of hydrofluorination
of tetrachloroethylene has been studied , and on this basis
using a method of pathways of complicated reaction was
developed kinetic model of the process of synthesis of
1,1,1,2-tetrafluoroethane.
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BARABANOV, MAKSIMOV
tetrafluoroethylene, vinylidene fluoride and other. The
The standard flow chart of the synthesis of ozone
technology of manufacturing of industrial fluoroolefins
by the pyrolysis of initial fluorochlorohydrocarbons in
the presence of water vapor is developed:
safe freons by the method of gas-phase catalytic
hydrofluorination is developed.
On the basis of the investigations conducted in
the Russian Federation are created and continue to be
created the industrial productions of ozone safe Freons
(Table 2).
It is interesting for more detailed study a new class
of ozone safe compounds, the fluorine-containing ethers
presented in Table 3.
In these processes the conversion of initial compounds
and the selectivity of fluoroolefins considerably exceed
the appropriate indices of the “dry” pyrolysis. Thus, at
the pyrolysis of difluorochloromethane at 750−850°C
the selectivity on tetrafluorine ethylene is 90−95% at the
conversion of difluorochloromethane ~80%, and at the
FLUORINE-CONTAINING OLEFINS
(1) In recent years in the Center “Applied Chemistry”
have been carried out wide investigations on the
perfection of the industrial technologies of fluoroolefins:
Table 2. Production of ozone safe Freons at the plants of Russian Federation
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INDUSTRIAL FLUORINE COMPOUNDS
1137
Table 3. Promissing ozone safe alternative compounds: ODP = 0, GWP < 300, (F/H + F) > 65%
S
pyrolysis of 1,1-difluoro-1- chloroethane at 800−840°C
the selectivity of process on the 1,1- difluorine ethylene
equals to 98−99% at the practically complete conversion
of initial 1,1-difluoro-1-chloroethane. The new technology
of obtaining tetrafluoroethylene is launched in the Kirovo-
Chepetsk chemical plant.
FLUORINE-CONTAINING INERT DIELECTRIC
LIQUIDS, OILS AND LUBRICANT
(1) In the Russian Scientific Center “Applied
Chemistry” is developed a series of the fluorine-containing
liquid dielectrics, obtained according to standard scheme
by the method of electrochemical fluorination.
(2) The technology of obtaining fluoromonomers for
the ion-exchange membranes has been developed and is
improved. At present the most effective membranes for
the fuel cells are the perfluorinated membranes of the
type of Nation (du Pont, USA).
The fluorine-containing liquids based on the perfluorin-
ated tertiary amines have the wide spectrum of application
due to their unique properties: low solidification point
(−100°C and below), low dielectric constant (~1.8 and
below), a wide interval of the boiling point (45−250°C),
high dielectric premeability (40−50 kV/mm) and
others.
In the Center “Applied Chemistry”also are developed
the studies on the creation of promising membranes for
the fuel cells and analogous designation on the basis of the
copolymers of tetrafluoroethylene and perfluoro(3,6-dioxa-
4-methyl-7-octene) sulfonylfluoride. The overall scheme of
the synthesis of this copolymer is represented below:
Some properties of the perfluorinated dielectric liquids
are given in Table 4.
Together with the application for the synthesis of
fluorine-containing compounds listed in Table 4, the
method of electrochemical fluorination is widely used
in the developments Russian Scientific Center “Applied
Chemistry”forthesynthesisofperfluorinemonocarboxylic
acids C2−C9 on the basis of different forms of source
material, and also petrorsulfo acids or of their derivatives,
for example, of perfluoroethylsulfofluoride, perfluoro(et
hylcyclohexylsulfofluoride) and other.
(2) In the Center “Applied Chemistry” is developed
and implemented a technology of manufacturing a per-
fluoropolyether, unique by their properties oligomers of
hexafluoropropylene oxide, of general formula
The films, which are used for creating the ion-
exchange membranes, are obtained by extrusion on the
basis of this copolymer.
RFO(CCF2O)nR'F
In Russian Scientific Center “Applied Chemistry”
are conducted studies on the development of works on
the creation of the highly effective fluorine-containing
membranes by means of the use of the copolymers from
new fluorinemonomers such as perfluoroalkylvinyl ethers
and similar compounds.
|
CF3
The technology for manufacturing these com-
popunds consists in oxidation of hexafluoropropylene
(CF3−CF=CF2) by oxygen at low temperature (−30° and
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BARABANOV, MAKSIMOV
Table 4. Perfluorinated dielectric heat-transfer agents.
below) at initiation with UV, by fluorine and by other
methods [3, 15].
range, good lubricating properties, radiation stability and
others.
The combination of these properties makes it possible
to use them in different areas of contemporary technology.
Some properties of perfluoropolyethers are given in
Table 5.
Scheme 5. Syntgesis of perfluoropopypropylenixides
SURFACTANTS
It is known that the fluorine-containing surfactants
occupy key place among the known surfactants. Thus,
the surface tension of the derivatives of perfluoroenanthic
and perfluoropelargonic acids is on the level of 15−16
dyn/cm. The low surface tension, and also the chemical
and thermal resistance of fluorine-containing sutfactants
of different structure determine their wide application in
the contemporary technology.
In the Center “Applied Chemistry” on the basis of
perfluoroenanthic (C6F13COOH) and perfluoropelargonic
(C8F17COOH) acids, and also on the basis of poly-
perfluoropolypropilene oxides of the formula
Stabilized oligomers produced by this method, possess
have boiling points in a wide range (from 50°C to 320°C
at 1 mm Hg), in combination with the low freezing point
(-60°C and below). Simultaneously perfluoropolyether
possess the combination of unique properties: they are
highly thermostable (to +450°C), chemically inert in
the highly aggressive media, not combustible, nontoxic,
possess the high dielectric characteristics, the little
changed viscosimetric properties in the wide temperature
and sulfo derivatives of the composition of
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INDUSTRIAL FLUORINE COMPOUNDS
Table 5. Some properties of perfluoropolyethers
1139
is developed a series of fluorine-containing surfactants
different structure:
Interaction of fluorine and graphite proceeds at the
temperature 550−650°C in two steps. In the first step
at the temperature 550−600°C in the regime close to
the adiabatic on the surface of the graphite particle is
formed a layer of solid poly-carbon fluoride (CFx)n. In the
second step in the absence of fluorine proceeds thermal
decomposition of (CFx)n at the temperature 600−650°C
with the formation of perfluoroalkanes.
anion active
(RFCOOMe, RFSO3Me, and others)
cation active
+
RFSONH(CH2)n−N(CH3)2]gas, and others
For providing thermostabilization of the zone of
reaction are used the reactors with the dynamic (stirred
or mobile) layers, the fluidized bed, which ascends by te
gas-dust flow or a freely falling layer of graphite.
Amixture of the gaseous reaction products of fluorine
and graphite with the following composition is obtained:
CF4 40−45 wt %, C2F6 20−25 wt %, C3F8 15−20 wt %,
C4F10 10 wt %.
|
RH
+
RFSO2NH(CH2)n−N−(CH3)2]gas,
|
RH
non-ionogenic
RFCONH(CH2 CH2 O)n−Η].
At the experimental plant of the Russian Scientific
Center “Applied Chemistry” was realized a number of
low-tonnage technologies on the fluorination of solids by
elemental fluorine with obtaining of the corresponding
fluorides: selenium, tellurium and iridium hexafluorides,
selenium and germanium tetrafluorides:
Fluoro-surfactants found wide application as bases for
the frothers: fire extinguishers for the extinguishing of the
burning petroleum products and polar liquids, additives
for oil and diesel fuel for the decrease in friction and
increase in the operational performances of machines
and mechanisms, in microelectronics at the production
of semiconductor materials at the cutting and grinding of
silicic plates, in the processes the cleaning articles, in the
galvanotechnics, etc.
GeO2sol +F2gas → GeF4gas +O2gas
Sesol +F2gas → SeF6gas
Sesol +F2gas → SeF4gas
,
,
,
SYNTHESIS OF FLUORINE COMPOUNDS
WITH THE USE OF ELEMENTAL FLUORINE
Tesol +F2gas → TeF6gas
,
Elemental fluorine found wide application as the
fluorinating agent in the synthesis of different fluorine
compound [16−18].
Irsol +F2 → IrF6gas
The industrial method of the synthesis of lowest
perfluoroalkanes is developed:
The processes of producing these compounds were
achieved in the shelf-type reactors, whose productivity
was hundreds kilograms per year. The reactors were
equipped with the scanning thermocouples, which made
Csol + F2 gas → CF4gas + C2F6gas + C3F8gas + C4F10gas
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BARABANOV, MAKSIMOV
Table 6. Inorganic fluorine-containing oxidizers
concentration in the gas of synthesis reached 90%,
nitrogen was basic admixture. The yield of difluoroamine,
tetrafluorinehydrazine and difluorodiazines did not
exceed 2−3%.
With the use of elemental fluorine is developed the
technology of producing a number of the inorganic
fluorine-containing compounds, which are used as the
oxidizers, etc
l
l
l
A list of these compounds is given in Table 6.
FLUORINE-CONTAINING COMPOUNDS
FOR MEDICINE
it possible to observe the temperature distribution in the
reactor, in this case the heat removal was accomplished
on the basis of free convection.
Atechnology is developed for the synthesis of nitrogen
trifluoride by the fluorination of melted NH4F·nHF by
gaseous fluorine:
In spite of the high aggressiveness of the initial
fluorinating reagents, many flourinated compounds,
polyfluorinated and perfluorinated in particular are of
great interest for medicine and biology owing to their
unique physicochemical properties, and are used widely in
the world as diagnostic, and therapeutic preparations.
Such compounds as perfluorodecaline, perfluorotri-
butylamine, perfluorooctyl bromide possess unique ability
to dissolve oxygen to about 45−50%. Taking into account
chemical inertness they are used as the gas transport
means for different purposes: for creating the artificial
blood substitute, in ophthalomology at the treatment of
the scaling of retina, in roentgenography and in other
areas.
NH4F·nHF2 gas +F2 gas → NF3 gas + NH4F·(n + m)HFliq
NF3 gas +NH4F·(n + m)HFliq → NH4F·nHFliq, where n < m.
Fluorination is conducted in the gradient-free reactor
with the high-speed mixer in the circulation loop, which
makes it possible to remove heat effectively on the
basis of forced convection and to maintain isothermal
regime of the process, and also to provide the maximum
contact area of gaseous fluorine with the melt. At this
method of the process performing, the productivity of
the reactor of fluorination reached 30 g of NF3 l–1 h–1 at
the conversion of fluorine up to 95%. Nitrogen trifluoride
Some fluorocarbons utilized in this direction in
medicine are represented in Table 7.
Introduction of these compounds into medical practice
is carried out in collaboration with medical establishments,
St. Petersburg Military Medical Academy and other.
Table 7. Fluorohydrocarbons for medicine
20
CF3
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1141
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