Katsukiyo Ito

Generation and thermal polymerization of 1-fluoro-2-phenylacetylene

Abstract Some routes to the synthesis of 1-fluoro-2-phenylacetylene were attempted. Although the halogen exchange of chloro- and bromophenylacetylenes and dehydrobromination of dibromofluorophenylacetylene were unsuccessful, defluorosilylation of 1,1- difluoro-2-phenyl-2-trimethylsilylethene (which was prepared by lithiation of bromodifluorovinylbenzene followed by silylation with chlorotrimethylsilane) with CsF gave an oligomer of fluorophenylacetylene. The reaction of the phenyldifluorovinylsilane with CsF in DMF in the presence of phenylazide afforded a 1,3-dipolar cycloadduct, fluorodiphenyl-1,2,3-triazole. Vapor phase vacuum pyrolysis of the phenyldifluorovinylsilane yielded the acetylene, which spontaneously polymerized.

Synthesis and polymerization of some ethynyl trifluoromethyl napthhalenes

Abstract Some bromonaphthoic acids were fluorinated with SF4 to bromo(trifluoromethyl)naphthalenes. Although a reaction of Grignard reagent of one of the bromides with Cl2C=CF2 gave low yield of a (dichlorofluorovinyl) (trifluoromethyl) naphthalene, lithio derivatives gave the desired ethynyl(trifluoromethyl) naphthalenes in improved yields after subsequent eliminations of the vinylic halogens with n –butyllithium. Polymerization of the acetylenes was carried out with photo-activated W(CO)6 catalyst to yield high-molecular-weight polymers.

Synthesis of some ethynyltrifluoromethylfurans and their polymerization

Abstract Some trifluoromethyl group substituted ethynylfurans were prepared according to the method of Okuhara. However, dichlorofluorovinylation of lithiated 2,3-bis(trifluoromethyl)- furan did not undergo so smoothly because of the electron- withdrawing trifluoromethyl groups and the initially substituted dichlorofluorovinyl group. Thermal, γ-ray induced, or oxidation polymerizations were investigated, and 1,4-diethynyl- 2,3-bis(trifluoromethyl)furan thermally polymerized to give an insoluble polymer in a violent exothermal reaction.

Modification of calibration curve for measurement of molecular weight of small polymers by gel permeation chromatography

Abstract When the molecular weight of a polymer is so small (M 1 [η] = − A 2 + A 1 M 1 2 ([η] = intrinsic viscosity; A1, A2 = constants), with polystyrene and polybutadiene used as the polymer samples. It is shown that the modification is adoptable for M

Radical polymerization initiated by primary radicals with similar structure to the end radical on the polymer

Abstract 1,1′-Azobisethyl-1-phenylethane and dimethyl-2,2′-azobisisobutylate decompose to yield 1-phenylethyl radical (PER) with a similar structure to the end radical on polystyrene (ST) and 1-methyl-1-methylcarboxylate ethyl radicals with that of poly(methylmethacrylate) (MMA). The data on the polymerizations of ST and MMA initiated by the above primary radicals at 60°C are treated by using some equations obtained before. Rate constants of termination between small polymeric radicals such as the primary radicals are estimated to be k tST : ST = 5.2 × 10 8 l mol −1 s −1 and k tMMA : MMA = 1.1 × 10 8 . A rate constant of primary radical termination between PER and polyMMA radical is also estimated to be k ti = 3.1 × 10 8 ( ⋍ k tST : MMA ). From these values, k tST : MMA ( k tST : ST k tMMA : MMA ) 1 2 is calculated to be 1.3, which is close to unity. However, it differs from o ⋍ 13 obtained before for cross-termination in polymerization between ST and MMA.

Some unsymmetrical azo compounds as initiators in radical polymerization

Abstract 2-Propylazodiphenylmethane (PAD), cyclohexylazodiphenylmethane (CAD), benzylazodiphenylmethane (BAD) and 1-phenylethylazodiphenylmethane (PEAD) were prepared. These materials decomposed through first order reactions. The ease of decomposition increased in the order: CAD

Gamma-Ray-Induced Polymerization of Fluorine-containing Pentadiene

cis型の3, 4, 5, 5, 5-ペンタフルオルペンタジエン-1, 3 (PFP) と2-メチル-3, 4, 5, 5, 5-ペンタフルオルペンタジエン-1, 3 (MPFP) のγ線塊状重合について+25～-196℃で検討した。 PFPはモノマーが液相, 低温固相のいずれのときにもtrans型の1, 4-付加のポリマーを与えるが, 液相で得られたポリマーの [η] は固相のときより著しく大きい。 一方, MPFPは液相のときに限って重合し, 1, 4-付加のポリマーを与えた。 液相におけるMPFPの重合速度はPFPの約1/10であった。 これらの結果はペンタフルオルペンタジエンの2の位置をメチル基で置換するとモノマーの反応性は小さくなるが, これは立体障害によると考えた。