James R. Griffith

The synthesis of highly fluorinated phthalonitrile resins and cure studies

Abstract The reactions of the potassium salts of 1,3- and 1,4-bis(2-hydroxy-hexafluoro-2-propyl) benzene 1 and 2 with tetrafluorophthalonitrile 3 afforded three isomeric products in each case with reaction at the 4-position of 3 predominating. When each mixture was submitted to the usual thermal conditions for phthalocyanine formation [1–5], the expected characteristic color change (blue or green) did not develop. Evidence was procured from our study which indicated that fluorine substituted on the phthalonitrile moieties hindered phthalocyanine formation. Instead, as an alternative reaction, some nucleophilic displacement of fluorine from the aromatic rings by the cyano substituents appeared to have occurred.

Synthesis and trimerization of fluorinated tertiary cyanates

Abstract Monofunctional and bifunctional bis(α,α-trifluoromethyl) cyanates were prepared by reaction of a fluorinated alkoxide with cyanogen bromide or cyanogen chloride. In the synthesis of bifunctional cyanates, the cyanation reaction required sufficient intramolecular separation for independent functional group reactivity. Monofunctional cyanates could be rapidly and quantitatively trimerized to cyclic cyanurates by catalytic quantities of AlCl 3 . Polymerization by trimerization of bifunctional cyanates under identical conditions was not successful, apparently, due to encasement of the catalyst by the polymer network.

Preparation of 1.3.5-tris(2-hydroxyhexafluoro-2-propyl) benzene and some of its derivatives

Abstract Grignard and lithium exchange methods have been used to prepare the polyfluoro alcohol, 1,3,5,-tris(2-hydroxyhexafluoro-2-propyl)benzene. Preparation of the tris glycidyl ether of this alcohol and other derivatives are reported.

The synthesis and attempted polymerization of an α,β,β-trifluorostyrene disubstituted by hexafluoro-2-propanol groups

Abstract The preparation of [(5-(trifluoroethenyl)-1,3-phenylene)bis[2,2,2-trifluoro-1- trifluoromethylethylidene]oxy]-bis[trimethylsilane] 2 in excellent isolated yield from the corresponding aryl iodide 4 is described. The synthesis features conversion of the known dialcohol 3 to the trimethylsilyl ether 4 which gave excellent protection against organometallic reagents and allowed the Pd(PPh 3 ) 4 catalyzed coupling with trifluoroethenylzinc bromide. Compound 2 exhibited good thermal stability with little propensity to form the corresponding F -cyclobutane dimer at room temperature.

Copper coupling reactions of 1,3-bis(2-hydroxyhexafluoro-2-propyl)-5-iodobenzene and its derivatives

Abstract Attempts to homocouple 1,3-bis(2-hydroxyhexafluoro-2-propyl)-5- iodobenzene (diol iodide) with copper fail to give the desired biphenyl tetrol. However, the dimethyl ether derivative of the diol iodide reacts smoothly with copper to give the biphenyl tetramethyl ether in good yields. The diacetate derivative of the diol iodide with copper gives only reduction of the aryl iodide. Heterocoupling of the diol iodide with 1,4-diiodoperfluorobutane gives a tetrol containing the -(CF 2 ) 4 -bridge.

Melt condensation and solution polymerization of highly fluorinated aliphatic polyesters

Abstract Highly fluorinated aliphatic polyesters were synthesized from a fluorodiol [HOCH2CH2(CF2)8CH2CH2OH] and both sebacoyl chloride and adipoyl chloride. Melt condensation polymerization followed by fractionation resulted in polymer samples with number average molecular weights in excess of 10 000. The use of solution polymerization yielded inferior results - with sebacoyl chloride the resultant polymers were of lower molecular weight, and with adipoyl chloride no polymer was formed. The fluoropolyesters have been characterized by 1H NMR and FT-IR spectroscopies, solubility, water contact angle, DSC and TGA. Crosslinking via peroxide of the polyester derived from sebacoyl chloride was successful; however, the resultant elastomeric-type material possessed residual crystallinity (from the parent polymer) and a low melting point.

The Synthesis of Fluorinated Acrylics Via Fluoro Tertiary Alcohols

Acrylic polymers of linear and of cross-linked varieties are important classes of materials, and the fluorocarbon polymers are likewise important for substantially different reasons. The broad resistance of fluorocarbons to physical and chemical attack suggests that acrylics could be enhanced by the introduction into the molecules of substantial amounts of fluorine, provided such an addition did not compromise the characteristic acrylic properties. Fluorocarbons also possess a range of unusual surface chemical properties which could make for greater versatility in the acrylics if imparted thereto. For example, a fluoroacrylic resin in the liquid, precured state is expected to be of low surface tension and excellent wetting capability for difficult-to-wet fillers, such as powdered Teflon, whereas the cured fluoracrylic can be expected to be relatively non-wetting and non-absorptive of most liquid systems, particularly those that are water based. In order to attempt such an enhancement of acrylic properties, the synthesis of a series of fluorine-bearing acrylics of various functionalities was undertaken.

The synthesis of a fluorinated phthalocyanine

Abstract The reaction of perfluoroalkylcopper with 4-iodophthalonitrile provides a convenient route to fluorinated phthalonitriles which readily form phthalocyanines in the presence of stannous chloride dihydrate. During the course of preparing 4-perfluoroheptylphthalonitrile 1 , a secondary reaction was observed when the reaction time was extended beyond two hours. This reaction involves the interaction of the orthodinitrile with copper and/or cuprous iodide to afford the phthalocyanine nucleus. This coaction is portrayed by the appearance of a green color in the reaction media.

Micellar interaction and its catalytic role in the polymerization of acrylamide catalyzed by bisulfite

Abstract A micellar interaction of cetyltrimethylammonium bromide (CTAB) with sodium bisulfite was observed, which coincided with a pH shift. This shift probably resulted from the formation of a complex that seemed highly susceptible to oxidation. Bisulfite-catalyzed polymerization of acrylamide was thus accelerated by the addition of CTAB to the polymerization system. The rate of acceleration of a CTAB-containing system was nearly three times as high as that of a CTAB-free nonmicellar system at pH = 5.3, which is an optimum for the highest rate for all cases of polymerization. It was observed that there were some salt effects in nonmicellar simple systems with a gradual increase in R p in proportion to the salt concentration. The unique kinetic feature of a CTAB-micellar system, was in sharp contrast, was a slow increase in R p at the CMC region but a sharp increase in R p at [CTAB] ⋍ 8.0 × 10 ṫ M . The R p approached a limiting value with further increase of CTAB concentration.

Synthesis of Reactive Fluoroaliphatic Diamines

Abstract The synthesis of “reactive” ( i.e. aminoacylated) fluoroaliphatic diamines [H2N(CH2)3C(ue5fbO)NHCH2CH2(CF2)nCH2CH2NHC(ue5fbO)(CH2)3NH2; n=4,8] has been accomplished through the use of peptide blocking group and coupling techniques. Also, the synthetic route to these diamines and their dihydrobromide salts has been improved over that of a recently published procedure.