全氟和多氟烷基磺酸的研究 XVI.以二氟甲磺酸作为二氟卡宾前体合成全氟或多氟烷基磺酸二氟甲酯

二氟甲磺酸(1)在室温下即可和五氧化二磷作用,但和全氟烷烃磺酸不同,它并不生成相应的磺酸酐。脱水后进一步消除二氧化硫产生二氟卡宾,二氟卡宾再插入二氟甲磺酸得到二氟甲磺酸二氟甲酯(2)。若有其它全氟烷基磺酸或全氟烷基羧酸存在时,也可得到相应的全氟烷基磺酸二氟甲酯(4)或全氟烷基羧酸二氟甲酯(6)。用三氯氧磷或二氯亚砜代替五氧化二磷和1作用,也得到类似的结果。对二氟卡宾生成的可能机理进行了讨论。     

全氟和多氟烷基磺酸的研究XX.二氟甲磺酸二氟甲酯与亲核试剂的反应

二氟甲磺酸二氟甲酯HCF~2SO~3CF~2H(1)和三氟甲碘酸二氟甲酯CF~3SO~3CF~2H(2)相比,在亲核反应中显出较大的差异.由于α-氢的存在,在一定程度上影响了它和亲核试剂的反应,如KF和2作用时得到HCF~3.但与1反应却只进攻其硫原子,得到HCF~2SO~2F(3).而KI与1作用时既可进攻硫又可进攻其烷氧基碳.其它亲核试剂如RCO~2^-,ArS^-等却只进攻1的硫原子.碱性较强的苯酚钠和1作用时除分别进攻硫和碳外,还可攫取其氢原子而产生二氟卡宾.若反应温度较低时,则仅攫取其二氟甲基的氢;若于90℃反应,则还可同时攫取二氟甲氧基的氢,碱性更强的乙醇钠与1反应时则是以攫氢为主.     

全氟和多氟烷基磺酸的研究——ⅩⅣ.由二氟甲基磺酰氟和亲核试剂生成二氟卡宾

亲核试剂和HCF_2SO_2F反应时,一般均进攻硫原子,而碱性较强的试剂如RO-(R=C_2H_5,R_FCH_2,C_6H_5,C_6H_5CH_2等),还可夺取其α-氢,此时并不生成CF_2—SO_2,而是在同时消除SO_2和F-后,产生二氟卡宾,再与ROH反应得到相应的醚ROCF_2H。     

全氟和多氟烷基磺酸的研究 ⅩⅦ.全氟烷磺酸二氟甲酯及其反应

和R_FSO_3CH_2R(1)及R_FSO_3CF_2R′_F(2)不同,R_FSO_3CF_2H(3)(RF=CF_3,3a;ICF_2CF_2OCF_2CF_2,3b;Cl_2CFCF_2OCF_2CF_2,3c;ClCF_2CF_2OCF_2CF_2,3d)和亲核试剂的反应较为复杂。除X-(X=F,Cl,I)及C_2H_5OH与3反应时只发生C—O键断裂外,其它试剂如RCO_2~-,C_6H_5S~-等既可进攻硫原子又可进攻碳原子,但以前者为主,碱性较强的试剂如RO~-还可夺取二氟甲基的氢原子而产生二氟卡宾,在3中由于甲基碳上存在两个氟原子,确实有着一定的屏蔽作用,因此阻碍了某些试剂对它的亲核进攻,但由于这个碳上还连有一个氢原子,所以这种屏蔽作用并不完全。     

全氟及α,α-二氯多氟烷基亚磺酸盐的反应

全氟烷基亚磺酸钠与溴水反应,得到全氟烷基磺酰溴(RfSO2Br),(但在乙腈,乙酸等有机溶剂中与溴反应,则生成溴代全氟烷.在碘化钾水溶液中,全氟烷基亚磺酸钠与碘反应,生成碘代全氟烷.α,α-二氯多币烷基亚磺酸钠在类似条件下与溴水反应,生成1-溴-1,1-二氯多氟烷,与碘在磺化钾水溶液中反应,生成1-碘-1,1-二氯多氟烷.1-溴-1,1-二氯多烷及1-碘-1,1-二氯多氟烷易对烯键加成,也可与连二亚硫酸钠在温和条件下发生亚磺化脱溴及脱碘反应.α,α-二氯二氟乙基亚磺酸钠在强酸中比较稳定,与强碱,氧化剂或还原剂发生反应,得到相应的产物.     

全氟和多氟烷基磺酸的研究 XI: 全氟3-氧杂戊磺酸全氟苯酯的合成及其和亲核试剂的反应

Pentafluorophenyl and p-chlorotetrafluorophenyl-3- oxaperfluoroalkanesulfonates XCF2CF2OCF2CF2SO3C6F4Y (1) (Y=F, p-Cl) were synthesized by the reaction of 3-oxaperfluoroalkanesulfonyl fluoride with the corresponding sodium phenoxide in good yield. 1 reacted with various nucleophilic reagents more readily than phenyl perfluoroalkanesulfonates. The reactivity of nucleophiles toward 1 is parallel to the pKa values of their corresponding acids. All nucleophiles used (except C6H5S^-) attacked sulfur of 1 giving RfSO2Nu. Treatment of 1 with CH3CO^-2 produced perfluorophenyl acetate. When equivalent amount of KF was added to the reaction mixture the yield of the acetate decreased and main product was acetyl fluoride. This showed that the reaction followed the course of intermediary mixed anhydride formed through the attack of CH3CO^-2 on sulfur of 1. But when 1 was treated with ArS^- the only reaction occurred was C-O scission of the sulfenate by the nucleophilic attack of ArS^- on the fluorinated benzene ring to give the totrasubstituted perfluorobenzene, 1, 2, 4, 5-C6F2 (SAr)4. In contrast to the nucleophilic reaction of the mono-substituted pentafluorobenzene it was shown that in all reactions with nucleophiles para or ortho di-substituted compounds such as ReSO3C6F4Nu were not found.     

抑铬雾剂F-53的研制带动了有机氟化学的发展

回顾了在抑铬雾剂F-53研制的推动下,在(i)亲核试剂进攻下全氟(或多氟)磺酸酯的S-O和/或C-O断裂方式(ii)全氟碘代烷的单电子转移反应(iii)二氟卡宾和三氟甲基化等方面所取得一些反应结果。     

全氟和多氟烷基磺酸的研究 X:在亲核取代反应中全氟烷基3-氧杂全氟烷基磺酸酯的唯一的硫-氧键断裂

Perfluoroalkyl 3-oxaperfluoralkanesulfonates XCF2OCF2CF2SO3CF2OCF2X (1) (X=CF2I (1a), CF2Cl (1b), HCF2 (1c), Cl2CF (1d)) reacted readily with various mucleophiles leading to S--O seission exclusively, thus 1 -- XCF2OCF2CF2SO2Y+XCF2OCF2COZ In the presence of a catalytic amount of halide (F-, Cl-, Br-, I-) and thiecyanate in diglyme 1 decomposed to give the corresponding sulfonly fluoride 2 (X=F) and acyl fluoride 3(Z=F). At room temperature 1 did not react with excess ethanol, but under refluxing for 12.5h, 1 was converted to 2 (Y=F) and 3 (Z=OEt). More powerful nucleophile ethoxide ion reacted readily with 1 at-60 - -50`C yielding Et2O and 3 (Z=OEt) but no 2 (Z=F). When the reaction was carried out at 80`C the yields of the products varied with the order of mixing of the reactants i.e. when 1 was added to excess ethoxide in ethanol, products are 3(Z=OEt), Et2O and 2(Y=F), but with ethoxide adding to 1 the yield of 2 (Y=F) was increased and that of ether decreased whereas the yield of 3 (Z=OEt) remained constant. Carboxylates (CF3CO2-, CH3CO2-) also caused S--O cleavage of 1 to give acetyl fluoride, 2 (y=F) and 3 (Z=F) as a result of decomposition of the intermediary mixed anhydride by the fluoride ion. In the same manner R2NH, C6H5NH2 reacted with 1 giving the products of S--O cleavage. In contrast to the nucleophilic reactions of α, α-di-H-perfluoroalkyl perfluoroalkanesulfonates (mainly C--O cleavage) it has been found that all nucleophies attack the sulfur atom of 1 exclusively. A possible interpretation is that the SN2 attack at sp3 carbon atom in highly fluorinated system is made impossible by the shielding effect of the two fluorine atoms in the alcoholic moiety and leaving the attack on the sulfur as the only alternative.     

氟烷基化和氟烷氧基化的研究 21: 锌存在下全氟烷基碘与亚硝酸阴离子的反应及其机理探讨

在过量锌粉的存在下, 全氟烷基碘(RFCF2I, RF:CF3CF2, Cl(CF2)n, n=3,5,7)(1)能与亚硝酸阴离子反应, 一步生成全氟烷基羧酸钠, 酸化后得到相应的羧酸. p-DNB不能阻止反应. NO3^-, SCN^-或F^-等阴离子在同样条件下和1反应只能生成1-氢-全氟烷烃.反应可能经锌单电子转移诱发的非链式自由基亲核取代机理.     

含氟磺酰胺和聚含氟磺酰胺的合成

为了合成聚含氟磺酰胺,进行了含氟磺酰氟与胺、含氟磺酰氯与胺及含氟磺酰胺钠盐与含氟磺酸酯或碘代烷反应的三种模型反应。制得了十七种新的含氟磺酰胺R_fO(CF_2)_2SO_2NR~1R~2(1a～1h),R~1R~2NSO_2R_fSO_2NR~1R~2(2a～2h)及[Cl(CF_2)_4O(CF_2_2SO_2NH(CH_2)_3]_2(3)。应用第三种合成途径制备了两种聚含氟磺酰胺,测定了它们的元素组成,IR.~(19)F NMR,M_n,T_g,断裂强度,热及化学稳定性。