1. Obtaining of Fluorine Modified Acrylates Ester Fragment.   

Esterification of acrylic and methacrylic acid by poly-fluorinated alcohols like R(CF₂CF₂)_nCH₂OH (R = H, F; n = 1-4) or F(CF₂CF₂)_nCH₂CH₂OH (n = 1-4) is carried out in presence of acidic catalyst sulfocoal and concentrated sulfuric acid in toluene medium at 110 ^oC for 6-8 h [80-83]. 2-perfluoroalkylethyliodides like (CF₃)₂CF(CF₂)₄CH₂CH₂I can also be used, but in this case  acrylic acid potassium salt is used and reaction is held in presence of C₆H₁₃N⁺Et₃ ^.I^- salt in isopropyl alcohol at 120 ^oC  for 5 h [84].

Fluorine containing acrylate synthesis can be carried out without isolating of corresponding alcohol. Thus, the authors of the work [85] showed such an opportunity, using two apparatus. Inside the first one the tetrafluoroethylene's telomerization is carried out in the presence of ethyl iodine, then reaction products are put inside the second apparatus, where the acrylic acid and tert-butyl alcohol are added, that leads to formation of corresponding acrylate.

Most often acrylic and methacrylic acid chloroanhydride and anhydride are used, the reaction is carried out in the presence of Et₃N.

    When H(CF₂CF₂)_nCH₂OH ( n = 1-4) linear fluorinated alcohols are influencing acrylic acid chloroanhydride in the presence of bases (KOH, NEt₃)  acrylates are formed in acetonitrile (1a-d) [30,80,81]. Here the base plays the definitive part. Thus when using potash (K₂CO₃) in acetonitrile we get corresponding ester of acrylic acid 1a in the mixture of initial alcohol; NEt₃ promotes the forming of only one product 1a, while KOH is very effective, however we get not only the 1a product we expected but also (2a) compound, which is a result of fluorinated alcohol addition according to C=C bond of reaction product 1a. It should be noticed that before was showed [86] the formation of addition product according to C=C bond of telomeric alcohols with acrylonitrile, though those authors carried out their reaction in the presence of sodium metal at  40 ^oC (yield is 73 %). At present conditions with acrylic acid chloroanhydride other telomeric alcohols along with 1b-d acrylates produce also 2b,c compounds.

 Thus, depending on fluorinated alcohol being used we should apply either triethylamine or KOH as a base, that dependes on their activity. Other fluorinated alcohols 3a-g  which have a branching in carbon chain especially in the beginning, or oxygen atoms are introduced into reaction with acrylic acid anhydride, at that acrylates 4a-g were obtained [30].

As the 3g alcohol used had an admixture of isomeric alcohol (11 %) the 4g acrylate formed is also a mixture of two isomers with the same composition. In case of  3d alcohol (mixture of diastereomers of 1:1.65 proportion) the formed  4d acrylate is also obtained as a mixture of two diastereomers, which proportion is 1:1.1 (according to chromato-mass-spectrometry data and NMR ¹H and ¹⁹F spectra).

     By the example of  3d alcohol reaction  they show the opportunity of methacrylic acid chloanhydride introducing into reaction forming the corresponding methacrylate  5 [58].

    Alcohols with spatially branched carbon chains are also effective for the acrylates synthesis [87,88]. You can look for the review on 2-phenyl-1,1,1,3,3,3-hexafluoropropan-2-ol using for polyacrylates synthesis in [89].

Esterification of methacrylic acid using secondary fluorocontaining alcohols in the presence of sulfuric acid isn't very much effective, that's why it is more preferable to use chloroanhydride or methacrylic acid anhydride.  Thus, morpholine fluorinated metacrylate is obtained with high yield when corresponding alcohol reacts with the methacrylic acid anhydride [60].

 Secondary alcohols like F(CF₂)_nCH(CH₂Cl)OH (n = 6,8,10) react with acrylic acid choloanhydride in the presence of Et₃N in benzene at room temperature for 2 hours forming the corresponding acrylate with high yield [90].

      1-(Polyfluoroalkyl)ethan-1,2-diols produce corresponding bis-metacrylates [73] when methacrylic acid chloroanhydride influence them. We should note, that process conditions essentially influence the proportion of monoester and diester. Thus, using the medium of pyridine, diethyl ether and boiling for 72 h- produces solely monoether [74], while in the system of triethylamine, diethyl ether, room temperature and  2 h time of reaction we get solely diether [73].

The authors of work [71] point out an important role of process conditions for the conversion level of fluorocontaining 1,2-diol with methacrylic acid chloroanhydride. 

 Initially only one of the two -OH groups of fluorocontaining 1,2-diol reacts. Perfluorinated group influences its reactivity. The authors of work [71] have established the following row of activity for some of 1,2-diols.

Other esters of methacrylic acid also react with  1,2-diol having perfluoralkyl group [91-93]  or with perfluoropolyether [94], at that the compounds, having acrylic and urethane fragments are formed.

Monoester, obtained by interaction of fluorocontaining 1,2-diol and acrylic acid chloroanhydride reacts with 2- methacrylethylisocyanate and as a result we get a compound with acrylates and urethane functions [95,96].

The authors of work [97] showed the opportunity of acrylates obtaining using perfluorolefines according to the following scheme and without using fluorinated alcohols.

 -fluoroacrylic acid fluoroanhydride, which is transformed into esters by reaction with telomeric alcohols[98-101], is obtained by interaction of  2,2,3,3-tetrafluoroxetane, alkali metals halogenides and dehalogenizing agent in aprotic bipolar solvents in the presence of radical polymerization inhibitor.

  Polymer materials based on fluorine modified acrylates and methacrylates according to ester fragment are of great interest of waveguides and optical glassfiber production because they are high transparent in the range of 1200-1600 nm, what is used for optical connection, along with their relatively low refracting indexes [102-104]. These properties can be enhanced by introducing fluorine atoms or other heavy atoms into carbon chain. Modified derivatives of initial monomer are of interest, they are obtained by introducing pentafluorophenyl group into eater part of molecule. The works [105,106], during which authors had carried out acrylates' synthesis using fluorine containing phenols, are devoted to this subject. It turned out, that a base used plays an important part. Thus in case of pyridine application the acrylate forming reaction goes together with polymerization process, while in the presence of 2,6-lutidine we get only acrylic acid ester.

    The reactions of pentafluorophenol with  -chloroacrylate, -fluoroacrylate and metacrylate were earlier described in the [102-104].

To be continued