1. The development of obtaining technology of partly fluorinated alcohols using interaction of teterafluoroethylene and hexafluoropropylene with alcohols in the presence of radical initiators.

Partly fluorinated primary alcohols like H(CF₂CF₂)_nCH₂OH (n = 1-6), the production of which is based on interaction of tetrafluoroethylene with methyl alcohol at increased temperature and pressure in the presence of peroxide initiator with decomposition point higher than 100 ^oC (tert-butyl diperoxide, tert-butylperoxy-2-ethylhexanoate , carboxylic acids peroxides, ethers peroxides, 2,5-bis-(tert-butylperoxy)-2,5-dimethylhexane and others) [7-21]. Thus alcohols ROH (R = CHCF₂CF₂CH₂, CF₃CHFCF₂CH₂) are obtained by heating of peroxide initiator (3,5-15,4 %) in alcohol at 110-120 ^oC  and pressure of 3,4-6,5 bar with control of fluoroolefine introduction and increasing of pressure up to 9 - 15 bar at 150 ^oC . The process is carried out at proportion of fluoroolefine / initiator (7.2 - 28.1 ) / 1 and in presence of 0.2-1.2 % polyfluorinated alcohol [8]. At these conditions the initiator decompose to radical and its reaction with alcohol is induced. For example, CHF₂CF₂CH₂OH with the yield of 99.8 % is obtained at reaction of methyl alcohol and tetrafluoroethylene in the presence of di(tert-butyl)peroxide [8].

The radical telomerization of tetrafluoroethylene with methyl alcohol regardless of the initiator's nature results in formation of mixture consisting of ,,-trihydroperfluoroalcohols  and their isomers H(CF₂)_nCH(OH)(CF₂)_mH, where n and m are numbers, divisible by 2. There are no indications regarding dependence of formed products' structure on used initiator. In the work [22] it was stated, that telomerization of tetrafluoroethylene using methyl alcohol at temperature within 65-75 ^oC and pressure equal to 15-18 bar using hydrogen peroxide as initiator results in formation of mixture consisting of 1,1,4-trihydroperfluorobutanol and 1,1,6-trihydroperfluorohexanol (alcohols with odd number of difluoromethylene groups) along with telomeric alcohols. Although the yield of these products is extremely low and amounts to 0.5-2 % of overall alcohols' sum. The formation of these products the authors account for the proceeding of process according to the following scheme:

Telomeric alcohols have found a wide application in fluoroorganic synthesis [23]. Thus, they are used for production of many fluorine containing materials and they also are semi-products first of all for production  partly fluorinated carboxylic [24-28] and -alkansulfine [23] acids, fluorinated ethers of glycols (via CH₂OH and CHF₂- groups)[23]. At the same time they in the presence of base act as active O-nucleophiles, which allow to receive the entire spectrum of ethers and esters [1]. The interest to the development of definitely specified alcohol obtaining technologies has sharply raised in recent years, when the effectiveness of their use at production of information-reproducing medias with reproducing layer able to read laser information was shown, and also it was shown in production of high effective surface active materials and photo developing compounds in photography. [29].

It is stated [30], that in addition to methyl alcohol other alcohols can be introduced into reaction of tetrafluoroethylene and hexafluoroethylene. At that the conditions of the process carrying out do not change (temperature 125 ^oC, pressure 0.8 MPa, radical initiator di-tert-butylperoxide). Although the conversion is not high (20.2 %) high selectivity is observed (95 % and more). In new patents the obtaining method of fluoroalkanols is based on the main process - the radical addition of methyl alcohol to tetrafluoroethylene [8]. The difference of patents is brought to optimization of process of  2,2,3,3-tetrafluoropropanol producing. It turned out [31-40], that process carrying out is more effective in the presence of CaCO₃. If at that the process temperature is kept within 60-65 ^oC (4 hours), then 2,2,3,3-tetrafluoropropanol [32] is formed, while at 125 ^oC and pressure equal to 0.8 bar (6 hours) the mixture of telomeric alcohols is obtained [32]. The best results for synthesis of 2,2,3,3-tetrafluropropyl alcohol were obtained at proportion: tetrafluoroethylene/methanol equal to 1/15 [33]. Thus, 2,2,3,3- tetrafluoropropyl alcohol is obtained in autoclave at proportion: tetrafluoroethylene/methyl alcohol (1/15) in the presence of CaCO₃ and di-tert-butylperoxide at 125 ^oC and pressure 0.8 bar during 6 hours [33,36]. It is stated [8,29,41], that hexafluoropropylene and thermal perfluorolefines RCF=CF₂ (R = CF₃, C1-C4-perfluoralkyl) react with methyl alcohol in the presence of dialkylperoxides [41], producing respective partly fluorinated alcohols. It is stated [34], that telomeric alcohols H(CFRCF₂)nCH₂OH (R = F, CF₃, n = 1; R = F, n = 2) obtained out of tetrafluoroethylene and hexafluoropropylene and methyl alcohol in the presence of di-tert-butylperoxide better produce under laser acceleration, UV-irradiation [35] or in the presence of base  (for example, NaOCH₃) [34] 

This information shows the general interest to developing of such type alcohols obtaining technologies, which availability essentially widens the sphere of practical application. At the same time the attention should be paid to mechanism of this process. It is generally accepted, that it includes generation of radical or anion radical under the action of initiator on alcohol, which leads the process [18-21]. It can be supposed, that present reactions as in the case of tetrafluoroethylene reaction with methyl alcohol in the presence of tert-butyl peroxide proceed through generation of intermediate radicals, generated out of alcohols by removal of hydrogen radical from -position under the action of tert-butyl peroxide with further interaction of these radicals with tetrafluoroethylene, producing oligomerization products. At using of tert-butyl peroxide excess partly fluorinated alcohols and very small amounts of tetrafluorethylene oligimerization products are obtained.

The reaction mechanism includes photochemical stimulation of fluoroolefine's double bound and its reaction with alcohol, resulting in generation of alkoxy-radical. Further reaction of last one mentioned with fluorolefine produces radical, which eliminate hydrogen radical from alcohol with formation of reaction product [42].

In the pilot variant there had been realized safe and wasteless production of partly fluorinated alcohols on the base of tetrafluoroethylerne and hexafluoroethylene and alcohols reactions in the presence of peroxide initiator with yield close to quantitive. It is stated, that chain length in partly fluorinated alcohols depends greatly on proportion of tetrafluoroethylene to initiator, that allows to obtain the telomeric alcohol needed. On the basis of obtained results the telomeric alcohols obtaining commercial plant was created, that really extended the possible producing methods of semi-products for fluoroorganic synthesis. The production of partly fluorinated carboxylic acids and dialkyl ethers is developed on the base of telomeric alcohols.

The syntheses of partly fluorinated secondary and tertiary alcohols out of tetrfluoroethylene and hexafluoropropylene [8] were carried out under following conditions: tetrafluoroethylene reacts with ethanol or iso-propanol at 125 ^oC, pressure 0,8 MPa and excess of tert-butyl peroxide. At these conditions 3,3,4,4-tetrafluorobutan-2-ol and 3,3,4,4-tetrafluoro-2-methylbutan-2-ol are formed with high yield. A small amount of tetrafluoroethylene telomerization products is also formed as by-products, they are extracted using simple distillation [43]. 

In case of hexafluoropropylene reaction with methyl and ethyl alcohols in the presence of tert-butyl peroxide only 2,2,3,4,4,4-hexafluorobutan-1-ol and 3,3,4,5,5,5-hexafluoropentan-2-ol are formed respectively. The opportunity of two radicals generation out of hexafluoropropylene according to assymentric double bound supposes the formation of two isomeric alcohols. In fact, at interaction of hexafluoropropylene and methyl alcohol the formation of two alcohols and 2-difluoromethyl-2,3,3,3-tetrafluoropropan-1-ol (ratio 93:5) is recorded, while the reaction with ethyl alcohol produces mixture consisting of two stable conformers (ratio 58:38) [43].

If chlorotrifluoroethylene is introduced into the reaction and  2,5-bis-(tert-butylperoxy)-2,5-dimethylhexane is used as radical initiator [44], that HClFCCF₂CH₂OH is obtained as main product with 95% selectivity.

UV-irradiation  can be an  initiator of these processes, at that the products of alcohols regioselective addition according to multiply bond of fluoroolefine are formed [45]. Both hexafluoropropylene and perfluorinated alkyl vinyl ethers react in such reactions [46]. As a rule, two regioisomeric adducts are formed, the conversion of fluoroolefine is rather high.

Radiolysis of internal perfluoroolefines by  ⁶⁰Co -irradiation in alcohol media results in formation of secondary alcohols [46]. Thus, perfluor-2-butene with methanol produces mixtures of threo/erithro in proportion of 1 to 1, while in case of perfluor-2-pentene with methyl alcohol reactions two isomeric products are formed in proportion 3:2. At the same time trans-perfluoro-4-methyl-2-pentene with methyl, isopropyl and ethyl alcohols produces only two diastereoisomers.

The free radical addition of alcohols, initiated by -irradiation also exists for non fluorinated cyclic olefins, at that the mixture of diastereoisomers is formed [47,48].

The cyclic alcohols also regioselectively reacts with hexafluoropropylene under the influence of -irradiation or in the presence of di-tert-butyl peroxide with formation of the replacement product of hydrogen atom at tertiary carbon. (table. 1) [49].

Table 1. Free radical addition of alcohols to hexafluoropropylene [49].

A - -irradiation, 20 ^oC, 10 days:  B - di-tert-butyl peroxide, 140 ^oC, 24 hours.

It should be noted, that for some alcohols the formation of dimeric products exists but in small amount. Thus, for cyclohexanol and exo-bisyclo[2,2,1]-heptan-2-ol the yield of dimeric product was 40 and 11% respectively.

In case of hexafluoropropylene reactions with different cyclic and acyclic diols in these conditions the replacement of hydrogen atom according to both tertiary carbon atoms with CF₂CHFCF₂ group takes place (table 1) [49].

It is not necessary to use alcohols for these purposes, you can base yourself on dialkyl ethers. Thus, the authors of the work [50] showed, that 1,2-dimethoxyethane, 1,2,-diethoxyethane, 1,5-diethoxyethyl ether and 2-methoxyethanol  in the presence of crown ether (18-crown-6) at -irradiation treatment react with hexafluoropropylene, producing replacement products of methoxyl group hydrogen  with 2-H-hexafluoropropenyl group.

Partly fluorinated alcohols are also obtained by reduction of respective esters of perfluorcarboxylic acids [51].

For example, methyl ether of perfluorooctanoic acid produces CF₃(CF₂)₆CH₂OH with the yield of 98.3% at 100% alcohol conversion.

If you use oxidizing agents, for example oxygen or fluorine derivatives in the presence of Al₂O₃ or copper powder, then instead of perfluoroolefine you can use partly fluorinated hydrocarbons. Thus, the oxidization of 1,1,1-trifluoroethane at these conditions results in formation of CF₃CH₂OH [52].

The fluorinated alcohols like R_FCH₂OH (R_F = C 1-10 perfluoroalkyl) are obtained with high yield and selectivity by fluoroalkylhalides RFCH₂X (X = halide) condensation with carboxylated salts like HA( CR¹R²)_mCOOM  (A = O, NH, M = alkali element, m = 3-5) at 100-180 ^oC , pressure 0.1 - 2 bar in 1,3-dimethyl-2-imidazolidone medium [53].

The process of Grignard reagent CF₃CF₂CF₂MgI and silicon containing aldehydes interaction is more complicated, resulting in formation of general formula R₃Si(CH₂)_nCH(OH)R_F (n = 1-3) alcohols   [54] .

Unsaturated alcohols like R_FCH=CHCH₂OH (RF = perfluoroalkyl, polyfluoroalkyl) are obtained by reaction of RFCF₂CH=CH₂ with water in the presence of acidic catalyst [55]. Analogously CF₃CF₂(CF₂CF₂)₂CH=CH₂ by water action in the presence of zeolite, containing silicon, at 300 ^oC is turned into alcohol CF₃(CF₂)₄CF=CHCH₂OH with yield of 80 % [55].