Anionic polymerization of 1,2-butylene oxide

Anionic polymerizations of 1,2-butylene oxide were carried out in vacuum-sealed dilatometers in the range of 30–60°C. Potassium terbutoxide and dimsyl sodium were used as initiators; dimethyl sulfoxide (DMSO) and mixtures of DMSO with tetrahydrofuran were solvents. The polymer products were analyzed by gel permeation chromatography and infrared spectroscopy. The object of the investigation was to obtain information on the mechanism of the reaction and to elucidate some of its kinetic aspects. It has been shown that the polymerizations occur by two different processes, depending on the choice of experimental conditions. One of the processes involves free ions and ion-pairs, the other, ion-pairs alone. In the first case, where dimethyl sulfoxide is used as solvent, the order of the reaction with respect to the initiator concentration far exceeds unity (～1.8), while in the second case, involving mixed solvents, the order of the reaction, for all practical purposes, is one.     

Ionic polymerization of 1,2-butylene oxide: GPC,NMR, and IR characterization of the reaction products

The triphenylmethyl hexafluoroarsenate-initiated cationic polymerization of 1,2-butylene oxide in dichloroethane between ?25 and +25°C and its sodium-initiated anionic polymerization in bulk at 20°C have been carried out. Gel permeation chromatography (GPC) molecular weight distribution curves of the reaction products are multinodal. Nuclear magnetic resonance (NMR) and infrared (IR) analyses show that the cationically prepared polymers are composed of cyclic oligomers and linear high-molecular-weight products, while the anionically prepared polymers contain only linear products some of which include double bonds. NMR analyses further reveal that the cationically prepared polymers consist of monomer repeat units, while the anionically prepared polymers are essentially made of side products originating from the reaction of 1,2-butylene oxide with the sodium mirror used as the anionic initiator.     

Micellisation of triblock copolymers of ethylene oxide and 1,2-butylene oxide: effect of B-block length

We have used pyrene fluorescence spectroscopy and isothermal titration calorimetry (ITC) to investigate the effect of hydrophobic-block length on values of the critical micelle concentration (cmc) for aqueous solutions of triblock poly(butylene oxide)-poly(ethylene oxide)-poly(butylene oxide) block copolymers (B(n)E(m)B(n), where m and n denote the respective block lengths) with hydrophobic block lengths in the range n=12-21. Combined with results from previous work on B(n)E(m)B(n) copolymers with shorter B blocks, plots of log(10)(cmc) (cmc in molar units and reduced to a common E-block length) against total number of B units (n(t)=n for diblock or n(t)=2n for triblock copolymers) display transitions in the slopes of the two plots, which indicate changes in the micellisation equilibrium. These occur at values of n(t)which can be assigned to the onset and completion of collapse of the hydrophobic B blocks, an effect not previously observed for reverse triblock copolymers. The results are compared with related data for diblock E(m)B(n) copolymers.     

Polymerization of 1,2-butylene oxide initiated by triphenylmethyl salts. I. Kinetics with 1,2-dichloroethane as solvent

1,2-Butylene oxide was polymerized in 1,2-dichloroethane in the temperature range ?20 to + 10°C. Triphenylmethyl salts of hexafluoroantimonate (Ph₃CSbF₆), hexafluoroarsenate (Ph₃CAsF₆), and hexafluorophosphate (Ph₃CPF₆) were employed as initiators. The reactions are characterized by a fast initiation process accompanied by rapid consumption of monomer. This initial stage is followed by a relatively slower polymerization during which the rate of monomer consumption is first-order in respect to monomer. Variation of the counteranion produces very little influence on the rate. The difference between the thermodynamic parameters found for the first and second stages of the reaction are explained on the basis of two different polymerization mechanisms. The linear dependence of rate on initiator concentration indicates that propagation takes place by ion-pairs only within the range investigated here.     

Synthesis and properties of novel aliphatic polycarbonate from carbon dioxide with 1,2-butylene oxide and ε-caprolactone

A new degradable aliphatic poly(butylene-co-e-caprolactone carbonate) (PBCL) was synthesized through the terpolymerization of carbon dioxide, 1,2-butylene oxide (BO) and e-caprolactone (CL), a polymer supported bimetallic complex (PBM) was used as a catalyst. The terpolymers prepared were characterized by FT-IR,1H NMR, 13C NMR, WXRD and DSC. The hydrolysis tests were carried out to appraise the degradability of the copolymers.     

Selective reduction of racemic 1,2-butylene oxide with (–)-diisopinocampheylborane in the presence of lithium chloride

Two equivalents of 1,2-butylene oxide was reduced with one equivalent of (–)-diisopinocampheylborane lithium chloride (1:0.1) system at 0° and ?20° to give optically active R-2-butanol, 22.0% e.e. and 22.6% e.e., respectively.     

Radiation-induced polymerization of 1,2-cyclohexene oxide in the plastic crystalline state

Radiation-induced solid state polymerization of 1,2-cyclohexene oxide has been investigated. By the differential thermal analysis and x-ray diffraction analysis, it was found that this compound has a phase transition point at ?81°C and behaves as a plastic crystal in the temperature range from ?81°C to ?36°C (melting point). The in-source polymerization proceeded not only in the plastic crystalline state but also in the ordinary crystalline state at temperatures below the phase transition point. The overall rate of polymerization and the rate of chain transfer to monomer in the plastic crystalline state were larger than those in the ordinary crystalline state by a factor of about forty, but the kinetic mechanisms were identical, i.e., the termination mechanisms were unimolecular in both solid states. In contrast, the kinetic mechanisms in the plastic crystalline state and in the liquid state were different. From these observations, the effects of molecular motion and molecular arrangement on the polymerizations of 1,2-cyclohexene oxide in the three phases were discussed.     

Rheological behavior of aqueous micellar solutions of a triblock copolymer of ethylene oxide and 1,2-butylene oxide: B10E410B10

A triblock copolymer of ethylene oxide and 1,2-butylene oxide, denoted B10E410B10, was prepared by sequential oxyanionic polymerization and characterized by 13C NMR spectroscopy and gel permeation chromatography. Micellization and the formation of micelle clusters in dilute aqueous solution, the latter a consequence of micelle bridging, was confirmed by dynamic light scattering, and average association numbers of the micelles were determined by static light scattering for T = 20-40 degrees C. The frequency dependence of the dynamic storage and loss moduli was investigated for solutions in the range of 5-20 wt %. Comparison with results for poly(oxyethylene) dialkyl ethers (10 wt %, T = 25 degrees C) indicated that the viscoelasticity of a copolymer with terminal B10 hydrophobic blocks was roughly equivalent to one with terminal C14 alkyl chains. The temperature dependence of the modulus was investigated for 15 wt % solutions at T = 5-40 degrees C. Superposition of the data led, via an Arrhenius plot, to an activation energy for the relaxation process of -40 kJ mol(-1). The negative value contrasts with the positive values found for poly(oxyethylene) dialkyl ethers and related HEUR copolymers with urethane-linked terminal alkyl chains. This difference is attributed to the block-length distribution in copolymer B10E410B10, whereby the activation energy of the relaxation process has a positive contribution from the disengagement of B blocks from micelles but a negative contribution from micellization. The negative value of the activation energy for solutions of B10E410B10 was confirmed by determining the temperature dependence of the zero-shear viscosity of its 15 wt % solution.     

三苯甲基衍生物的合成

以二苯基(对甲氧基)苯基氯甲烷和溴乙酸乙酯反应得到3,3-二苯基-3-(对甲氧基)苯基丙酸乙酯,然后水解和酰氯化得到3,3-二苯基-3-(对甲氧基)苯基丙酰氯,再用LiAlH4还原得到其醇,再氧化得到3,3-二苯基-3-(对甲氧基)苯基丙醛。     

1-(Triphenylmethyl)allyl potassium :conformational preference and [1,2]-rearrangement

Upon treatment with the superbasic 1 : 1 mixture of butyllithium and potassium tert-butoxide cis- and trans-1,1,1-triphenyl-2-butene as well as 4,4,4-triphenyl-1-butene undergo a hydrogen/metal exchange to afford 1-(triphenylmethyl)allyl potassium [4,4,4-triphenyl-2-butenyl potassium] which can exist in two stereoisomeric forms. Torsional equilibration leads to an endo/exo-ratio of approximately 50 : 50. Novel endo-stabilizing interactions are discussed to rationalize this result. At temperatures around or above 0°C a phenyl 1,2-migration, though no 1,4-migration takes place.     

Cationic copolymerization of propylene oxide with tetrahydrofuran. VI. Triphenylmethyl hexafluorophosphate as initiator

Copolymerizations at ?10 to +20°C of propylene oxide (PO) with tetrahydrofuran (THF) were carried out in 1,2-dichloroethane (DCE) under dry, inert atmospheric conditions. Reactions were initiated by triphenylmethyl hexafluorophosphate (TPM-HFP) and subsequently followed by vapor-phase chromatography. Vacuum-dried residual copolymer products (RCP) were analyzed by gel-permeation chromatography (GPC), vapor-pressure osmometry (VPO) and nuclear magnetic resonance spectrometry (NMR). Attempts to homopolymerize THF in equimolar mixtures of DCE and THF at THF/TPMHFP ratios of 1:1 × 10^?3 proved futile, while the homopolymerization of PO under identical operating conditions took place quite readily. Copolymerizations of PO–THF mixtures were easily carried out with high and often complete consumption of both monomers though, more often than not, THF was the principal residual monomer at the end of the 24 hr reaction period since, under no circumstances could additional THF be polymerized when the PO charged was completely consumed. Linearity of plots of ?ln (C₀/C) versus time showed the reactions to be first order with respect to both PO and THF concentrations. Influence of temperature reveals, via Arrhenius plots and overall activation energies (16.0 kcal/mole for PO and 13.0 kcal/mole for THF), that the initiator system functions similarly to other reported systems. Reactivity ratios (0.26 for PO and 0.80 for THF) indicate that monomer units tend to alternate along the chains rather than form extended segments of a given kind. This is supported by NMR analyses of RCP samples. Bimodal GPC distributions observed in the present study suggest that the copolymerization reaction may be proceeding by either a dual mechanism or a two-step process.     

Photoinitiated cationic polymerization of limonene 1,2‐oxide and α‐pinene oxide

Limonene 1,2‐oxide (LMO) and α‐pinene oxide (α‐PO) are two high reactivity biorenewable monomers that undergo facile photoinitiated cationic ring‐opening polymerizations using both diaryliodonium salt and triarylsufonium salt photoinitiators. Comparative studies showed that α‐PO is more reactive than LMO, and this is because it undergoes a simultaneous double ring‐opening reaction involving both the epoxide group and the cyclobutane ring. It was also observed that α‐PO also undergoes more undesirable side reactions than LMO. The greatest utility of these two monomers is projected to be as reactive diluents in crosslinking photocopolymerizations with multifunctional epoxide and oxetane monomers. Prototype copolymerization studies with several difunctional monomers showed that LMO and α‐PO were effective in increasing the reaction rates and shortening the induction periods of photopolymerizations of these monomers. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013     

1,2-disubstituted ethylene in radical polymerization

Effect of Tsinkamin-02 additive on characteristics of electrolytically fabricated zinc electrode for backup power sources was studied. Its influence on how a zinc powder is formed, deposition process parameters (current efficiency by zinc, cathodic polarization), and utilization factor of the active substance of the negative electrode in a nickel-zinc power source discharged in a high-intensity mode was determined. The component concentrations of the electrolyte used to deposit the zinc powder were optimized. An explanation was suggested for the mechanism of Tsinkamin-02 action.     

Synthesis and polymerization studies of 1,2-dimethyleneoctafluorocyclohexane

1,2-Dimethyleneoctafluorocyclohexane has been prepared by the pyrolysis of 2-chloro-methyl-1-methyloctafluorocyclohexane. Free radicals initiate the polymerization of the diene in both bulk and emulsion systems to give a highly crystalline (mp 214–218°C) polymer that has an all-cis 1,4-structure. The polymer is insoluble in common laboratory solvents, but will dissolve in perfluorokerosene above 175°C and in 2,5-dichlorobenzo-trifluoride above 150°C. This diene is not polymerized by cationic, anionic, or Ziegler-Natta catalysts. The diene is readily copolymerized with many common monomers to give soluble, high molecular weight polymers. Relative reactivity ratios have been measured with styrene by the Fineman and Ross method and Q–e parameters for the diene have been calculated.     

Anionic polymerization of propylene oxide

The anionic polymerization of propylene oxide with the use of potassium tert-butoxide and naphthalene sodium as initiator and dimethylsulfoxide, tetrahydrofuran and mixtures of both as solvent was investigated. The reactions were carried out in vacuum-sealed dilatometers over the temperature range 20?60°C. The products were analyzed by gelpermeation chromatography and infrared spectroscopy. The object of the investigation was to obtain information on the mechanism of the reaction and elucidate some of its kinetic aspects. It is shown that the polymerization occurs by two different processes depending on the experimental conditions: one involving free ions and ion-pairs, the other, ion-pairs alone. In the first case, where DMSO was used as solvent, the order of the reaction with respect to the initiator is greater than unity (～1.7), while in the second case, involving the mixture of DMSO and THF and ion-pairs alone, the reaction order is only one. Transfer to monomer is believed to take place only in the strongly dissociating DMSO medium, where free ions are present.     

Radiation-induced polymerization of isobutylene oxide

In the absence of oxygen, liquid isobutylene oxide is polymerized by high energy radiation. The resultant polyethers may possess the same gross structures as those prepared by Lewis acid catalysis: The reaction is characterized by (1) a small, apparent activation energy (2.7 kcal/mole), (2) a polymerization rate proportional to the first power of the dose rate, (3) inhibition by Lewis bases, and (4) moderate inhibition by free-radical scavengers. The molecular weights of the polymers increase with decreasing temperatures of polymerizations. These results will be discussed in terms of a cationic propagation mechanism.