The publication of the journal is supported by
SIA "P&M-Invest" Ltd and INEOS RAS
Volume # 4(41), July - August 2005 — "Fluorine containing polymer materials based on unsaturated acids modified according to ester fragment and their practical application "

Fluorine Notes, 2005, 41, 1-2

FLUORINE CONTAINING POLYMER MATERIALS BASED ON UNSATURATED ACIDS MODIFIED ACCORDING TO ESTER FRAGMENT AND THEIR PRACTICAL APPLICATION
 

V.B. No a,  G.G. Furin b

a  PIKO Enterprise LLC , 8 Galterina str., Perm City Russia 614113.

b  Novosibirsk Institute of Organic Chemistry named after N.N. Vorojtsov SD of RAS,  9 Academic Lavtrentiev avenue, Novosibirsk, 630090, Russia E-mail : furin@nioch.nsc.ru

     Here we discuss the approach to the fluorine modification of acrylates and maleates ester fragment using partly fluorinated alcohols and acrylic, methacrylic and maleic acids' derivatives to synthesize them. We also discuss the reactions involving multiply bond and carboxylic group of maleic acid fluorine containing mono-ester and acrylic acid esters.  We analyze acrylates polymerization processes their co-polymerization with other olefines,  and also fluorine containing polymers' characteristics. We also take a look at practical application fields of such polymer materials. 

Contents

      Introduction.

1. Approaches of fluorine modified ester fragment acrylates synthesis.

2. Maleic acid fluorine containing mono- and diesters obtaining.

3. The synthesis of sulfoacids derivatives based on fluorine containing acrylic and maleic acids esters and their salts. 

4. Polymerization and co-polymerization of fluorine containing acrylates.

5. Practical application fields of fluorine containing polymer materials based on fluorinated acrylates and maleates.


Introduction

At every stage of technical progress the role and direction of fundamental researches, especially the ones of new class of organic compounds is initiated by society's need in new materials, which can't exist without creating fundamentally new, possessing high consumer properties and able to work under more severe conditions materials. Indeed fluorine compounds meet such requirements and can play a defining part in intensification and production simplification of many goods without fundamental reconstruction of existing manufactures. Perfluorinated compounds are the compounds of our present and future. The production of such perfluorinated organic compounds has already been developed. Such compounds meet up-to-date requirements by thermophysical and dielectric characteristics, they can be used in a wide temperature and thermal loads ranges their practical application field is also found. The entire replacement of hydrogen atoms for fluorine in the organic molecule results in sharp changing of properties, what has been used to create new generation materials possessing excellent working characteristics. They began to be used for metals and alloys atmospheric and salt corrosion defense, and also as lubricating oils, applied at aggressive conditions, in hydraulic liquids, as heat-transfers, liquids for vacuum pumps, operating in corrosion active medium, as additives for oils, used at high pressure in different compressors etc. In terms of scope and level of scientific achievements and scale of their commercial implementation the fluorine chemistry is now a powerful independent scientific and technical direction of organic chemistry.

The production of fluorine containing materials doesn't only depend on the level of our knowledge regarding fluororganic compounds properties, but also on their practical application perspective, which is dictated by development of technical conception.

Among fluoropolymers [1-3] an independent and intensively developing class of polymers and co-polymers, acrylates and methacrylates [3-7] fluorine modified fills an important place. It occurs because of the fact, that acrylates based on fluorinated alcohols posses unique properties, especially high hydro- and oleophobic abilities. It makes a base to obtain polymeric suspensions for fibrous articles surface proccessing and creating coatings for non-organic materials. In most cases water and oil-repellent agents are obtained out of polymers, which main chains are poly-acrylic and polymetacrylic acid, turning acid groups into fluorocarboxylic chains ester ones (C8-C10) [8-12]. They are surfactants, sorbing at the edge of phase break sharply change surfaces' nature and properties. Their specific surface activity, which can't be reached in case of hydrocarboxylic component, made a base to create materials, which achieved a strong position among commercial products. Surface energy of coatings made of such fluorine containing polymers is low, and that's why they can be hardly dampened and are characterized by low friction coefficients comparatively to other solid materials. All said above allows creating materials for field of technics. The field of their practical application includes different directions. For example, we can point out the water and oil-repellent properties adding chemicals for fabrics [13], materials for microelectronics [14], surfactants (SAM) for olefin's polymerization processes [10], systems stable to electronic strike and X-rays [15-17] etc.

Here we see the chemical enterprises re-orientation to science intensive articles production, new technologies and new products.

The synthesis of fluorine modified monomers (acrylates) is mainly carried out by interaction of acrylic and metacrylic acids with linear partially fluorinated alcohols, that was boosted by patent claim [18]. The interest for modified acrylates is constantly growing a great file of information on this class compounds, especially in the field of practical application. If earlier at acrylates synthesis they used linear poly-fluorinated aliphatic alcohols, then by now the interest for introduction opportunity of hydophilic fragments such as ether bounds, nitrogen atoms etc into main chain of molecule is shown. Such opportunity for acrylates can be implemented in hydrocarboxylic skeleton of ester part.

Acrylic and metacrylic acids are commercially produced in huge amounts. Because of this the researchers paid a lot of their attention to developing of partly fluorinated alcohols obtaining methods and technology and other unsaturated organic compounds co-polymeriazation proccesses [1,3]. The requirements for properties of polymer materials used for techniques, in regards to wearing qualities, weather resistance, incombustability, antiadhesive and anti-corrosive properties, dielectrical and other special characteristics remain high. Owing to so strict requirements for such materials and in spite that their production is complicated and price is high compare to other plastics they work up the market. Combination of fluorine containing polymer materials based on acrylates improves characteristics of chemical and atmosphere stable coatings.

In this review we demonstrate the last decade achievements in the field of synthesis and application of polymer materials based on acrylates and maleates, containing fluorine modified ester fragments, synthesis of which is based first of all on use of partly fluorinated alcohols. These alcohols production technology is based on the following chemical transformations. .

1) Alcohols like RFCH2CH2OH are produced out of RFI perfluoroalkyliodides, which at first are introduced into reaction with ethylene with further saponification of new sub-derivative [19,20].


The method is implemented in commercial scale.

2) Synthesis method of H(CF2CF2)nCH2OH (n = 1-15) telomeric alcohols is based on telomerization of tetrafluoroethylene and other fluorolefines in methyl alcohol or aliphatic alcohol in presence of peroxide initiators [21-55].


This process is implemented commercially.

3) Alcohols like RFCH2OH are obtained by reduction of polyfluorinated carbonyl containing compounds (perfluorocarboxylic acids ethers [51,56-69] and diketons and ketofluoroanhydrides [70]) by NaBY4 or LiAlH4 action.


4) Synthesis of diols with polyfluoroalkyl groups was developed by Paleta and his co-workers. It is carried out by reaction of partly fluorinated alcohols and 4(hydroxymethyl)-2,2-dimethyl-1,3-dioxolane tosylate with further deprotonation of reaction product [71-79].


Acrylic acid itself and methacrylic acid or its chloroanhydride, anhydride, maleic acid or its anhydride are used as unsaturated carboxylic acids.


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

Fluorine Notes, 2005, 41, 1-2

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