Structural characterization of hydroxyl terminated polyepichlorohydrin obtained using boron trifluoride etherate and stannic chloride as initiators

Epichlorohydrin was polymerized using boron trifluoride etherate or stannic chloride as initiators in presence of diols. The molecular weight of the polymer increased with increase in the ratio of epichlorohydrin to the diol in the reaction mixture. The polymers were characterized by IR, proton NMR and ¹³C NMR analysis. The terminal hydroxyl groups of the polymers were characterized by derivatizing them using trifluoro acetic anhydride and analyzing the resulting ester by NMR. Both primary and secondary hydroxyls were present in the polymer. The primary hydroxyl terminals of the polyepichlorohydrin (PECH) prepared using stannic chloride initiator were twice the amount of that present in the polymer prepared using BF₃ etherate initiator. The ¹³C NMR spectrum of PECH prepared using BF₃ etherate indicates that the polymer backbone is rich in H-T diad. Both cationic and co-ordination mechanisms operate during the polymerization in the presence of SnCl₄ and the ¹³C NMR spectrum of the polymer showed more of T-T and H-H sequences.     

Review and Future of Ionic Polymerization with Special Emphasis on Carbonyl Polymerization

Ionic polymerization received prominence about 35 years ago when isobutylene was commercially polymerized by two processes which, with some modifications, are still used today [1]. One process uses aluminum chloride as the initiator and the other uses boron trifluoride; both cationic polymerization processes are carried out at low temperatures. A number of additional commercial processes based on cationic and anionic polymerization have since been developed. Cyclic ethers, most prominently tetrahydrofuran, are polymerized cationically to relatively low molecular weight hydroxyl terminated polyethers which have found important uses in polyurethanes. Trioxane is copolymerized with a small amount of ethylene oxide to form a useful copolymer of polyoxymethylene. Other products which are of interest are the polymers of caprolactone and epichlorohydrin and polymers of various epoxides, mainly those of glycidyl ethers which are most commonly known as epoxy resins. Anionic polymerization on a commercial scale has developed along the lines of styrene and isoprene polymers. Stereorubber, stereoregular 1,4-cis isoprenes, are based on lithium initiators and were introduced in the middle 1950s. Triblock polymers based on A-B-A block polymers of isobutylene with styrene as endblocks and prepared from living polymers have been known since the early 1960s.     

Homopolymers and copolymers of vinyl ethers of rosin-derived alcohols

Two vinyl ethers of rosin-derived alcohols were homopolymerized with free-radical and cationic initiators. A polymer was obtained from the vinyl ether of the alcohol from Foral in good conversion by free-radical initiators but it was not a high molecular weight product. Cationic initiators were more effective; boron trifluoride etherate proved to be best. All of the homopolymers were obtained as white powders with high crystallinity. Copolymerizations of the vinyl ethers and vinyl chloride have been studied with the use of free-radical initiators. Cationic-initiated copolymers of the vinyl ethers and isobutyl vinyl ether were studied. Those containing less than 20% of the rosin vinyl ethers were rubbery, of high molecular weight, and could be crosslinked with peroxide.     

Polymerization of allyl(vinyl phenyl) ethers and reactions of the resulting polymers

Solution polymerizations of allyl(o-vinyl phenyl)ether and allyl(p-vinyl phenyl)ether with cationic and radical initiators were investigated. Soluble polymers were formed in polymerizations with boron trifluoride etherate and with benzoyl peroxide. In polymerization with azobisisobutyronitrile the polymerization in dilute solution gave a soluble polymer, whereas that in concentrated solution gave a crosslinked, insoluble one. For informationon the polymerization behavior some infrared and ultraviolet spectroscopic investigations of the soluble polymers were made. From these results it appears that polymers with pendant allyl groups are formed in polymerization with boron trifluoride etherate at low temperature, and polymers containing pendant vinyl groups and allyl groups are obtained with the two types of radical initiator. Copolymerizations of these monomers with ethyl vinyl ether and styrene with the use of boron trifluoride etherate were sucessfully effected. Such reactions as Claisen rearrangement, crosslinking induced with radical initiators, and epoxidation with perbenzoic acid were examined for the polymers prepared in the polymerization with boron trifluoride etherate. Good results were obtained for the former two reactions. However, the latter was unsuccessful.     

Haloaldehyde Polymers. XIV. Endgroups in Polychloral

Chloral polymers prepared by anionic polymerization have alkoxide endgroups as terminal ends at the end of this polymerization. The initiating anion has, as expected, no influence on the type of terminal group formed. Polychloral with terminal alkoxide ends degrades easily thermally to monomeric chloral. Alkoxide endgroups in polychloral do not readily react with alkylating or acylating agents, although partial stabilization has been observed when alkoxide-terminated polymers were allowed to stand for periods of time; the endgroups seem to react either with impurities or with excess chloral in side reactions. With protic acids, alkoxide-terminated polychloral is transformed into hydroxyl-terminated polymer of higher thermal stability. Studies of the initiation step of the chloral polymerization revealed that above the ceiling temperature of polymerization, strong nucleophiles, such as soluble tertiary butoxide, initiate quantitatively, but polymerization does not proceed until the mixture is cooled. When chloral is initiated with weaker nucleophiles such as chloride or carboxylates, the initiation equilibrium is not on the side of the initiated species, although it shifts effectively as polymerization proceeds; with carboxylates as initiators the ester group has been found incorporated as the initial endgroup in polychloral. With sufficient amounts of lithium tertiary butoxide as anionic initiator, polychloral of low molecular weight was prepared. This polymer does not react with end-capping reagents (other than PCl₅) as does high molecular weight polychloral; in spite of considerable effort it was not possible to prepare low molecular weight soluble polychloral or oligomeric polychloral. Polychloral prepared with cationic initiators is thermally more stable than unstabilized anionically initiated polychloral but is generally crumbly and incoherent. The end-groups of such polymers are usually hydroxyl endgroups. Identification of endgroups of the polymers has been done where possible by IR spectroscopy, for the initiation reaction by NMR spectroscopy, but for high molecular weight insoluble polymers almost exclusively by comparative thermal polymer degradation.     

Ionic Polymerization of 1,2-Butylene Oxide: NMR Study of the Reaction Products

An NMR study on the reaction products of the ionic polymerization of 1,2-butylene oxide has been carried out. Polymers prepared via a cationic mechanism by using a trityl salt as the initiator are built up of repeat monomer units, and the propagation reaction follows Bernoullian statistics. Polymers prepared via an anionic mechanism with the use of sodium metal as initiator, on the other hand, are not made up of repeat monomer units, and the propagation reaction follows a first-order Markov statistics. In the cationic polymers the mean chemical shifts of the triads and tetrads move upfield on replacing m dyads by r dyads; however, the pentads move downfield on changing m by r. In the anionic polymers the mean chemical shifts for the triads and tetrads of the ethyl group along with the pentads of the methine protons move upfield whereas tetrads associated with the remaining methylenes move downfield on replacing m dyads by r dyads as well as on replacing 0-C6H4CI2 by CCU or DMSO-de as the solvent for recording the spectrum. The anionic polymer M-b, which is rich in double bonds and hydroxyl groups, has relatively lower values for the geminal couplings J_AB and the vicinal couplings J_AX.and J_BX as compared to those obtained with polymer M-a, which has practically no double bonds and very few (if any) hydroxyl groups. The appearance of the methylene protons in polymer M-b as well as the coupling constants J_AB., J_AX, and J_Bxvary on changing the solvent from O-C6H4Cl2 to CCh or DMSO-de.     

Synthesis of functional polymers bearing cyclic carbonate groups from (2-oxo-1,3-dioxolan-4-yl) methyl vinyl ether

(2-Oxo-1,3-dioxolan-4-yl) methyl vinyl ether (OVE) was synthesized with high yield by addition reaction of glycidyl vinyl ether with carbon dioxide using tetrabutylammonium bromide (TBAB) as a catalyst. OVE was also prepared by reaction with β-butyrolactone or sodium hydrogencarbonate in the presence of TBAB as the catalyst. Poly [(2-oxo-1,3-dioxolan-4-yl) methyl vinyl ether] [P(OVE)] was obtained with high yield by cationic polymerization of OVE catalyzed using boron trifluoride diethyl ether complex in dichloromethane. Polymers bearing pendant 5-membered cyclic carbonate groups were also prepared by radical copolymerization of OVE with some electron-accepting monomers. Furthermore, addition reaction of P(OVE) with alkyl amines yielded the corresponding polymer having pendant 2-hydroxyethyl carbamate residue with high conversions. © 1994 John Wiley & Sons, Inc.     

Specific phenomena during the copolymerization of trioxane and ethylene oxide

We, at Asahi Chemical in Japan, have industrialized three types of polyacetal resins, that is, the acetal homopolymer, copolymer and block copolymer using anionic, cationic and anionic polymerization techniques, respectively. During this industrialization, we observed various phenomena, which were not previously reported. First, the authors outline the three technologies for producing each type of polyoxymethylene from an industrial viewpoint. Next, the authors discuss a newly found reaction during the induction period of the trioxane and ethylene oxide copolymerization. Experimental proof of direct ring expansion between the reaction of trioxane and ethylene oxide is discussed and various novel cyclic compounds are also shown. To the best of our knowledge, this reaction may be the world's first experimental proof of direct ring expansion of the reaction of a cyclic monomer. Third, the authors also discuss the newly founded morphospecific polymer from the copolymerization of trioxane and ethylene oxide using boron trifluoride dibutyl ether as an initiator.     

Synthesis of a side chain liquid crystalline polymer containing the cholesteryl moiety via ROP and “click” chemistry

Propargyl monocholesterylsuccinate (ChPS) was prepared through the esterification of monocholesterylsuccinate with propargyl alcohol, and poly(3-azidomethyl-3-methyloxetane) (PAMMO) was synthesized via cationic polymerization, using boron trifluoride etherate as catalyst and benzyl alcohol as initiator in methylene chloride. Through the copper-catalyzed “click” reaction between the azide group on PAMMO and the alkyne group on ChPS, a side chain liquid crystalline polymer containing the cholesteryl moiety (Ch-SCLCP) was obtained. The “click” reaction was confirmed by IR, ¹H NMR, ¹³C NMR, and GPC studies. The resulting polymer showed thermotropic mesophase as judged by polarized optical microscopy (POM) and differential scanning calorimetry (DSC).     

Cationic-Initiated Ring-Opening Polymerization of Cyclopropenone Ketals. II. Novel Polymers via Bromine as Polymerization Initiator

Cyclopropenone ketals are functionally capable of undergoing both vinyl and ring-opening polymerization. In a previous paper we reported ring-opening polymerization via boron trifluoride etherate initiation to yield a polymer of complicated structure. However, this previous study showed that conventional cationic initiators yield an exceptionally stable carbocation intermediate which is essentially incapable of further propagation. This paper reports the effective use of the unconventional cationic initiator, elemental bromine, to yield polymer, proposed to be formed by a sequence of steps which involve initial addition of bromine to the cyclopropene double bond, followed by electrophilic ring opening of the brominated cyclopropane ring and propagation via the carbocation intermediate formed. At least three different and simultaneous pathways are believed to be involved. The resulting polymers have [Mbar]_n values in the range of 10,000.     

Cationic polymerization of vinyl compounds in the presence of tetra-n-butylammonium salts

The effects of salts were examined in cationic polymerization of vinyl compounds. Cationic polymerization of styrene was carried out at 0°C, with acetyl perchlorate, stannic chloride, stannic chloride–trichloroacetic acid and boron trifluoride etherate as catalysts. Tetra-n-butylammonium perchlorate, fluoroborate and iodide were used as salts. The presence of small amounts of the salts changed both the polymerization rate and the molecular weight of polymer considerably. The consideration of various effects led to the conclusion that the results are explicable principally on the basis of counterion exchange. To confirm this, the copolymerization of 2-chloroethyl vinyl ether with γ-methylstyrene was investigated at ?78°C. The copolymer composition curve when stannic chloride was used as catalyst was changed and coincided with that of polymer obtained with acetyl perchlorate catalysis when the perchlorate salt was added. This supports the concept of counterion exchange.     

A facile method for the N-formylation of primary and secondary amines by liquid phase oxidation of methanol in the presence of hydrogen peroxide over basic copper hydroxyl salts

N-formylation reactions by catalytic oxidation of methanol in the presence of primary or secondary amines and hydrogen peroxide has been investigated using a liquid phase reaction system over basic copper hydroxyl salts. A series of basic copper hydroxyl salts was prepared by the conventional precipitation method using aqueous ammonia and sodium hydroxide as precipitating agents. PXRD, SEM, FT-IR, BET were employed for physical characterization of the prepared basic copper hydroxyl salts. The composition of the catalytic material obtained was found dependent on the nature of the anion associated with the copper salt precursor. The copper hydroxyl chloride catalyst has shown the best catalytic performance in terms of the reaction rate and product selectivity whereas for the copper oxide catalyst the reaction rate was extremely slow. It is interesting to observe that 4-piperidone protected with acid-sensitive functional groups such as N-acetyl piperazine and ethylene glycol can also be formylated from moderate to good yields by these catalysts.     

SYNTHESIS OF A COMB GRAFT COPOLYMER VIA RING OPENING METATHESIS POLYMERIZATION CATALYZED BY SUPPORTED RHUTHENIUM CARBENE COMPLEX

Comb graft copolymers (CGC), a special kind of the hyper-branched polymer series, have unique and excellent properties [1,2]. Synthesizing CGC via ring opening metathesis polymerization (ROMP) of cycloolefinyl macromonomer catalyzed (initiated) by the molybdenum carbene complex (Schrock complex) is a newly-developed method [3,4]. Though showing excellent catalytic behavior the complex has the disadvantage of highly moisture and oxygen sensitive and is hence operation-inconvenient. We repor…     

Synthesis of novel ladder polymers of poly(3,4‐dihydro‐2H‐pyran‐2‐methanol)

Polydi(3,4‐dihydro‐2H‐pyran‐2‐methyl) esters of oxalic, adipic, and phthalic acids were prepared at different temperatures in the presence of different cationic initiators, namely, the boron trifluoride/diethyl ether complex system, anhydrous ferric chloride, and p‐toluene sulfonic acid. The obtained polymers were hydrolyzed under basic conditions, and the polydispersity indices of these polymers were determined before and after hydrolysis. The results are discussed to shed some light on the ability to use this analysis to investigate the precise structure of the obtained polymers and to predict the ability of these polymers to form ladder or semiladder polymers. Characteristics of such polymers were dependent, to some extent, on the type of crosslinks and the cationic initiators used for polymerization as well as the reaction temperature. It seems possible to optimize the conditions leading to formation of ladder or semiladder polydi(3,4‐dihydro‐2H‐pyran‐2‐methyl) esters of oxalic acid and adipic acid, respectively. The ladder structure was confirmed through determination of the polydispersity index before and after hydrolysis of the polymer formed at different temperatures and through computer‐aided molecular modeling. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 3909–3915, 2002     

SYNTHESIS OF A COMB GRAFT COPOLYMER VIA RING OPENING METATHESIS POLYMERIZATION CATALYZED BY SUPPORTED RHUTHENIUM CARBENE COMPLEX

5－Chloromethyl-2-norbornene was synthesized via Diels-alder reaction of cyclopentadiene and allyl chloride using a polymer supported boron trifluoride as the catalyst,and was then lithiated and used to initiate a livcing anionic polymerization of styrene to prepare a macromonome,5-polystryl-2-norbornene NB-PS,Comb graft copolymer PNB-g-PS was synthesized via ring opening metathesis polymerization of the macromonomer under the catalysis of ruthenium carbene complex RuCl2(PPh3)2(=CCHtBu)and its polymer supported correspondent.Experimetal results showed that the behavior of both the supported boron and supported ruthenium catalysts are superior to their unsupported counterparts.The possible promotion mechanism of the tailor-made supports is discussed.     

载体化络合催化开环歧化聚合合成梳形接枝共聚物研究

由环戊二烯（CPD）及烯丙基氯（AC）经聚合物支载三氟化硼催化的Diels-Alder反应合成了5-氯甲基-2-降冰片烯（NB-CH2Cl),锂代后用以引发甲基丙烯酸甲酯（MMA）及苯乙烯（S）的活性阴离子聚合,合成了带聚合物取代基的降冰片烯大分子单体NB-PMMA及NB-PS。在聚合物支载钌卡宾络合物催化作用下进行所合成大分子单体的开环歧化聚合反应（ROMP）,合成了二种接枝于开环歧化聚降冰片烯（PNB）主链的梳形接技共聚物PNB-g-PMMA及PNB-g-PS。实验结果表明所研制聚合物支载硼、钌络合物催化性能明显优于对应非支载活性种。     

Ionic Polymerization of α-lsopropyl-a-methylstyrene

The polymerization of p-isopropyl-α-methylstyrene was carried out with anionic and cationic initiators. Polymers prepared in bulk through an anionic mechanism yielded narrowly dispersed products whereas those prepared with sodium-naphthalene complex in solution as well as with cationic initiators gave broad or bimodal distributions when analyzed with gel-permeation chromatography. The presence of microgels was also detected in these latter polymers and has been attributed to chain transfer reactions leading to branching and possibly crosslinking. The comparison of the proportions of different protons in these polymers, as computed from their nuclear magnetic resonance and infrared spectra, with those obtained for a polymer of regular structure suggests that reactions originating from the isopropyl group, along with substitutions on the benzene ring, are responsible for the anomalous structures.     

Synthesis and characterization of poly(ethylene oxide‐co‐ethylene carbonate) macromonomers and their use in the preparation of crosslinked polymer electrolytes

Methacrylate‐functionalized poly(ethylene oxide‐co‐ethylene carbonate) macromonomers were prepared in two steps by the anionic ring‐opening polymerization of ethylene carbonate at 180 °C, with potassium methoxide as the initiator, followed by the reaction of the terminal hydroxyl groups of the polymers with methacryloyl chloride. The molecular weight of the polymer went through a maximum after approximately 45 min of polymerization, and the content of ethylene carbonate units in the polymer decreased with the reaction time. A polymer having a number‐average molecular weight of 2650 g mol^?1 and an ethylene carbonate content of 28 mol % was selected and used to prepare a macromonomer, which was subsequently polymerized by UV irradiation in the presence of different concentrations of lithium bis(trifluoromethanesulfonyl)imide salt. The resulting self‐supportive crosslinked polymer electrolyte membranes reached ionic conductivities of 6.3 × 10^?6 S cm^?1 at 20 °C. The coordination of the lithium ions by both the ether and carbonate oxygens in the polymer structure was indicated by Fourier transform infrared spectroscopy. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 2195–2205, 2006     

Microwave Effects Due to Anionic or Cationic Initiators in Emulsion Polymerization Reactions

Summary: Emulsion polymerization reactions were performed under microwave irradiation and conventional heating using anionic or cationic initiators and surfactants. Microwave irradiation promoted higher reaction rates for both initiators and surfactants, in comparison with the conventional heating. The effect of high power microwave irradiation was studied using a method of cycles of heating and cooling, where rapid polymerization reactions were obtained. In the reactions with anionic initiator and surfactant, a decrease in the particle diameters was observed with microwave heating, and even smaller particles were obtained using high power microwave irradiation. Moreover, the decrease in the particle size was acompanied by an increase in the polymer molecular weight. On the other hand, these effects were not observed for reactions with cationic initiator and surfactant.     

Copolymers of vinyl and vinylidene chlorides with alkyl acrylates

High-molecular-weight copolymers of vinyl chloride and ethyl or butyl acrylate were prepared in high conversion and yield in the presence of boron trifluoride as the acrylate ester complexing agent. When the vinyl chloride monomer is in excess of equimolar amounts, the resulting copolymers are alternating; and when the alkyl acrylates are in excess, acrylate-rich copolymers are obtained. Ethylene–vinyl chloride–ethyl acrylate and propylene–vinyl chloride–ethyl acrylate terpolymers were also obtained with an ethyl acrylate content of 50 mole %. The relative reactivities of propylene, vinyl chloride, and ethylene in these polymerizations were 5.4, 3.8, and 1.0, respectively. Vinylidene chloride–ethyl acrylate copolymers that are nearly alternating and rich in acrylate or in vinylidene chloride have also been prepared. The monomer reactivity ratios for vinylidene chloride and ethyl acrylate in the presence of boron trifluoride are considerably lower than in its absence.