Polymerization of Acrylonitrile Initiated by the System Tetramethyl-2-tetrazene and p-Toluenesulfonic Acid

The polymerization of acrylonitrile (AN) initiated by tetramethyl-2-tetrazene (TMT) and p-toluenesulfonic acid (TSA) in dimethylformamide (DMF) was studied. The polymerization was confirmed to proceed through a radical mechanism. The initial rate of polymerization R was expressed by the equation: R_p = k[TMT]^0.6 [TSA]^0.46 [AN]^1.35. The overall activation energy for the polymerization was estimated as 20.7 kcal/mole. In the absence of monomer, the reaction of TMT with TSA was also studied kinetically by measuring the evolution of nitrogen. From these results and ESR measurement of the TMT/TSA system, a possible initiation mechanism is proposed.     

Vinyl polymerization. Part 268. Polymerization of acrylonitrile initiated by the system of tetramethyl tetrazene and bromoacetic acid

The polymerization of acrylonitrile (AN) initiated by the system of tetramethyl tetrazene (TMT) and bromoacetic acid (BA) in dimethylformamide (DMF) was studied. The TMT–BA system could initiate the polymerization of AN more easily than TMT alone. The polymerization was confirmed to proceed through a radical mechanism. The initial rate of polymerization R_p was expressed by the equation: R_p = [TMT]^0.62-[BA]^0.5[AN]^1.5. The overall activation energy for the polymerization was estimated as 9.4 kcal/mole. In the absence of monomer, the reaction of TMT with BA in DMF was also studied kinetically by measuring the evolution of nitrogen gas. The reaction was first-order in TMT and first-order in BA; the rate data at 49°C were k₂ = 9.1 × 10^?2l./mole-sec., ΔH? = 17.0 kcal/mole, and ΔS? = ? 6.6 eu. In addition, the treatment of TMT with BA in benzene led to the formation of tetramethylhydrazine radical cation, which was identified by its ESR spectrum. On the other hand, the relatively strong interaction between TMT and DMF was observed by absorption spectrophotometry.     

Catalytic Action of Metallic Salts in Autoxidation and Polymerization. VII. Polymerization of Methyl Methacrylate by Cobalt(ll) or (III) Acetylacetonate-Dioxane Hydroperoxide

Abstract

Polymerization of methyl methacrylate by Co(II or III) acetylacetonate-dioxane hydroperoxide [abbreviated as Co(acac)2, Co(acac)₃, and DOX HPO, respectively] was carried out in dioxane solvent, and the differences in polymerization rate and the degree of polymerization between two initiating systems were compared. Co(acac)₂-DOX HPO for the initiation of the polymerization system was more effective than Co(acac)₃-DOX HPO. The polymerization rate equations for both initiating systems obtained from kinetic data were as follows. For Co(acac)₂-DOX HPO initiating system: R_p=k [M]^3/2[Co(acac)₂]^1/7[DOX HPO]^?     

Vinyl Polymerization. 282. Vinyl Polymerization Initiated by Dimethylhydroxylamine-Titanous(lll) Chloride Redox System

Abstract

The polymerization of vinyl monomers initiated by dimethylhydroxylamine hydrochloride (DHA)-titanous(III) chloride redox system has been studied in water under a nitrogen atmosphere. In the polymerization of methyl methyacrylate (MMA) initiated by the above system, the rate of polymerization has been found to be proportional to [DHA]^0.5 for DHA concentrations of less than 2.06 × 10^?3 mole/liter, whereas at higher concentrations the rate tends to fall rapidly. The rate has also been found to be proportional to [Ti(m)] ^0.58 and to [MMA] ^1.0. The maximum rate of polymerization has been observed at a 1:1 molar ratio of DHA to Ti(III). The polymerization proceeded via a radical mechanism. The overall activation energy was estimated as 5.5 kcal/mole. It has been suggested that the reduction of dimethylhydroxylamine by titanous(III) chloride yields the dimethylamino radical, which initiates vinyl polymerization. An examination of the initiating capacity of the initiator system for the polymerization of some vinyl monomers has also been made.     

含胺基功能性单体的聚合研究——ⅫⅠ.丙烯腈在N-丙烯酰-N′-苯基哌嗪及其聚合物作为增感剂下的光聚合

The photopolymerization of AN by using N-acryloyl-N'-phenylpiperazine (APP) and N-methacryloyl-N'-phenylpiperazine (MPP) as sensitizers under UV irradiation has been investigated. The corresponding polymerization kinetic equations are as follows:Rp [APP]^0.81[AN]^0.61 R_p [MPP]^0.48[AN]^0.77 R_p [P(APP)]^0.53[AN]^0.78 From the fluorescent analysis, it was confirmed that APP, MPP and P(APP) not only initiated the polymerization of AN but also entered into the chains of AN polymer. The photopolymerization mechanism for exciplex formation of AN with above sensitizers was proposed.     

Vinyl Polymerization. 269. Polymerization of Methyl Methacrylate Initiated by p,p'-Dimethoxydiphenyldiazomethane

Using p,p'-dimethoxydiphenyldiazomethane (DMDM) as initiator, the polymerization of methyl methacrylate (MMA) in benzene or in bulk was carried out. The initial rate of polymerization, R_p, was found to be expressed by the following equation:

R_p = k[DMDM]^0.53 [MMA]^0.84

The polymerization was confirmed to proceed by a radical mechanism. The over-all activation energy for the polymerization in benzene was calculated as 19.3 kcal/mole. The rate of thermal decomposition of DMDM was also measured in benzene and the rate equation was obtained as follows:

k_d (sec^?1) = 1.0 × 10¹⁵ exp (^?29.1 kcal/RT) (for 50-80°C)

Explanations of these observations are discussed in connection with those of the preceding papers.     

含胺基功能性单体的聚合研究——ⅫⅠ.丙烯腈在N-丙烯酰-N′-苯基哌嗪及其聚合物作为增感剂下的光聚合

关于含有芳香叔胺基的烯类单体,我们曾报道过N,N-二甲氨基苯乙烯,N-(4—N′,N′-二甲氨基苯基代丙烯酰胺(DMAPAA),N-(4-N′,N′-二甲氨基苯基代甲基丙烯酰胺(DMAPMA),甲基丙烯酸-4-N,N-二甲氨基苄脂(DMABMA),8-丙烯     

Vinyl polymerization. 275. Polymerization of vinyl monomers photosensitized by tetramethyltetrazene

A study of the photopolymerization of vinyl monomers in the presence of tetramethyltetrazene (TMT) was made. TMT was found to act as an effective sensitizer. In the photopolymerization of vinyl monomers such as methyl methacrylate or styrene the rate of polymerization was expressed by the equation: R_p = k[TMT]^1/2[monomer]. The chain-transfer constant of TMT under ultraviolet irradiation was estimated to be 3.8 × 10^?2 for the above monomers. A linear correlation was found to exist between the reactivity of dimethylamino radical toward the vinyl monomers and e values for the corresponding monomers.     

Phase-Transfer Catalysis: Free-Radical Polymerization of Methyl Methacrylate using K2S2O8-Quaternary Ammonium Salt Catalyst System. A Kinetic Study

Abstract

The kinetics of phase-transfer-agent-assisted free-radical polymerization of methyl methacrylate using K₂S₂O₈ as the water-soluble initiator and triethylbenzylammonium chloride (TEBA) as the phase-transfer catalyst (PTC) was investigated in toluene-water biphase media at 60°C. The effect of varying [MMA], [K₂S₂O₈], [TEBA], [H⁺], the ionic strength of the medium, and the temperature on the rate of polymerization (R _p) was studied. R _p was found to be proportional to [MMA]², [K₂S₂O₈]¹, and [TEBA]^0.5. Based on the kinetic results, a mechanism involving initiation of polymerization by phase-transferred S₂O₈ ^2- and termination by Q⁺ (quaternary ammonium ion) is proposed.     

Polymerization of Acrylonitrile Initiated by 1,4-Dimethyl-1,4-bis(p-nitrophenyl)-2-tetrazene

The polymerization of acrylonitrile (AN) initiated by 1,4-dimethyl-1,4-bis(p-nitrophenyl)-2-tetrazene (Ie) was studied in dimethylformamide (DMF) at high temperature. The polymerization proceeds by a radical mechanism. The rate of polymerization is proportional to [Ie]^0.64 and [AN]^1.36. The overall activation energy for the polymerization is 21.5 kcal/mole within the temperature range of 115-130°C. The chain transfer of Ie was also undertaken over the temperature range of 120-135°C. The activation parameters for the decomposition of Ie at 120°C are k_d = 2.78 × 10^?6 sec^?1, ΔH^? = 40.8 kcal/mole, and ΔS^? = 19.5 cal/mole-deg, respectively.     

亚硝酸钠引发丙烯腈聚合的研究

研究了亚硝酸钠引发硝酸溶液中丙烯腈的聚合反应。测得表现聚合速度 Rp=Ae~(-10,800/RT)[AN]~2.2[NaNO_2]~(0.17-1.0)[HNO_3]~(1.0-0.67 丙烯腈-丙烯酸甲酯共聚合反应中竞聚率分别是γ_An=0.96,γ_MA=1.17,表明聚合反应是按自由基机理进行。 根据聚合动力学和红外光谱分析,认为以亚硝酸钠引发硝酸溶液中丙烯腈的聚合反应与电解或金属溶蚀过程中的次级引发相同。     

以阳离子乳化剂进行丙烯酸丁酯－苯乙烯乳液共聚的动力学研究

采用十二烷基二甲基苄基氯化铵（１２２７）乳化剂，对丙烯酸丁酯（ＢＡ）－苯乙烯（Ｓｔ）进行乳液共聚，研究了影响聚合速度的各种因素，得出了聚合速率方程和表观活化能。     

Metal compounds in free-radical processes. III. Polymerization of acrylonitrile initiated by copper (II) nitrate in presence or absence of triphenylphosphine

The bulk polymerization of acrylonitrile (AN) initiated by copper (II) nitrate, Cu(II), in the absence of light has been studied. The rate of the AN polymerization may be expressed in the Cu(II) concentration range from 5 × 10^?4 to 1 × 10^?1 mole 1.^?1 by the equation, R_p = k₅[Cu(II)]^0.68, where k₅ = K_AN[AN]/(1 + K_AN[AN]). From the spectrophotometric measurements the values of 0.70 l./mole and 0.08 l, mole were obtained for the equilibrium constant at 20 and 60°C, respectively, K_AN = [C]/[AN]-[Cu(II)], corresponding to the formation of the complex C from acrylonitrile and copper (II) nitrate. An addition of triphenylphosphine (C₆H₅)₃P into the polymerization system reduces R_p, and no polymerization takes place at all provided [(C₆H₅)₃P]/[Cu-(II)] ≧ 5. The retardation effect of (C₆H₅)₃P on the polymerization of AN initiated by Cu(II) is attributed to a competitive reaction of Cu(II) with (C₆H₅)₃P in which Cu(II) is reduced and the product of this reduction CuNO₃·2(C₆H₅)₃P is inactive with respect to the polymerization of AN.     

Cyclic Acetal-Photosensitized Polymerization. 9. Photopolymerization of Triallylidene Sorbitol

Abstract

The photopolymerization of triallylidene sorbitol (TAS) was carried out in benzene at 40°C without the usual initiator. The polymerization of TAS was found to be initiated with the ester radical generated via the acetal radical from TAS by means of photoirradiation. The rate of polymerization and the molecular weight of polymer were small due to the degradative chain transfer, It was kinetically investigated from the standpoints of the degradative chain transfer by the allylidene group and the cyclization by three double bonds. The following results were obtained: (1) The relation between the rate of polymerization, R_p, the monomer concentration, [M], could be expressed by [M] /R_p = (A[M] + B)/(3[M] + C), where A, B, and C were constant; (2) the ratio of the rate constant of unimolecular cyclization to the total rate constant of bimolecular propagation and the chain transfer of uncyclized radical was estimated to be 3.0 mol/dm³. A small amount of cyclopolymerization took place.     

Redox-Initiated Polymerization of Vinyl Monomers with Cu(II)=Cyclohexanone System in Acetonitrile Medium. A Kinetic Study

The kinetics of the oxidation of cyclohexanone (CHN) by hydrated copper(II) perchlorate (HCP) in an acetonitrile medium has been studied. The orders with respect to [CHN] and [HCP] were found to be one each. This HCP + CHN redox system has been used for the polymerization of acrylonitrile, methyl methacrylate, and methyl acrylate. The rate of polymerization was proportional to [CHN]^0.5, [HCP]^0.5, and [M]^1.8. Based on the above results, a probable mechanism for oxidation and polymerization is proposed.     

STUDY ON THE POLYMERIZATION OF ACRYLONITRILE INITIATED BY POLYPROPYLENE-BASED VANADYL POLYIMIDODIACETATE——THIOUREA REDOX SYSTEM

The present paper deals with the kinetics of polymerization of acrylonitrile (AN) initialed by the redox system of polypropylene-based vanadyi polyimidodiacetate (PV)-thiourea (TU)in aqueous sulfuric acid in the temperature range from 25 to 40℃. The polymerization rate was measured by varying the concentrations of monomer, vanadyl polyimidodiacetate, thiourea and sulfuric acid. The overall rate of polymerization was summarized asRp=2.2×10~5e~(-6.560/RT) [AN]~(1.0)[PV]~(0.50)[TU]~(1.5)[H_2SO_4]~(2.0)The molecular weight of polyacrylonitrile based on the experimental data was:(?)=k 1/T [pv]~(0.50)[TU]~(1.5)[H_2SO_4]~(2.0)These results indicated that the chain radicals are terminated by combination and/or disproportionation rather than chain transfer. The cooperation effect of carboxylic groups and the macromolecular field effect of polymer supporter are the characters of vanadyl polyimidodiacetate such as the case reported in early paper.     

Epoxide Polymerization and Copolymerization with Carbon Dioxide Using Diethylaluminum Chloride-25,27-Dimethoxy-26,28-dihydroxy-p-tert-butyl-Calix[4]arene System as a New Homogeneous Catalyst

ABSTRACT

Previously unknown substituted chelate phenolatoaluminum chloride, (25,27-dimethoxy-p-tert-butylcalix[4]arene-26,28-diolato) aluminum chloride, was derived from the reaction of diethyl-aluminum chloride and 25,27-dimethoxy-26,28-dihydroxy-p-tert-butylcalix[4]arene at reactants 1:1 mole ratio. It was applied successfully for the polymerization of propylene oxide and cyclohexene oxide, and their copolymerization with carbon dioxide, leading to respective oligomers and co-oligomers. The catalyst structure and the structure of the obtained low-molecular-weight polymers and copolymers were studied using NMR spectroscopy. Poly(propylene oxide) obtained in the presence of the studied catalyst appeared to contain isotactic diads predominantly, whereas the obtained poly(cyclohexene oxide) did not exhibit any significantly prevailing sequences of either isotactic nor syndiotactic diads. The polymerization mechanism has been proposed and discussed in view of the obtained results.     

Syndiotactic Polystyrene Polymerization Results Using a Titanium(III) Complex,Cp*Ti(OMe)2 and Implications to the Mechanism of Polymerization

Abstract

Syndiotactic polystyrene (SPS) is a new semi-crystalline engineering thermoplastic synthesized via homogeneous Ziegler/Natta type catalysis. The polymer was first prepared in 1985 by Idemitsu Kosan Co. Ltd. [1] and has been under joint product and process development by Idemitsu Petrochemical Co. Ltd. and Dow Plastics since 1988. Recently, Dow and Idemitsu announced that they will complete semicommercial plant construction in 1996 utilizing a unique continuous polymerization process.     

Transition metal complexes bearing 2,6-bis(imino)pyridyl: Synthesis,structure, ethylene polymerization/ oligomerization studies

A series of new complexes {2,6-bis[1-((2-methyl-4-methoxyphenyl)imino)ethyl]pyridine}Cl₂ [M=Fe(II) (2), Co(II) (3), Ni(II) (4), Cu(II) (5), Zn(II) (6)] have been synthesized. At 25°C, using 500 equiv of methylaluminoxane (MAO), the activities of Fe(II), Co(II) catalysts can reach 4.02 ×10⁶ g/mol-Fehatm for ethylene polymerization and 3.98×10⁵ g/mol-Cohatm for ethylene oligomerization. The effects of polymerization conditions such as reaction temperature, Al/M molar ratio and time on the activity of catalyst have been explored.

     

Polymerization of Styrene Initiated by 1,4-Dimethyl-1,4-bis(p-anisyl)-2-tetrazene

Abstract

The polymerization of styrene (St) initiated by 1,4-dimethyl-1,4-bis(p-anisyl)-2-tetrazene (1a) was studied kinetically in benzene. The polymerization proceeds through a radical mechanism. The rate of polymerization is proportional to [1a]^0.5 and [St]^1.0. The overall activation energy for the polymerization is found to be 81.2 kJ/mol within the temperature range of 65 to 80°C. The activation parameters for the decomposition of 1a at 70°C are k_d = 1.88 × 10^?5s^?1, δH? = 133.1 kJ/mol, and δS? = 29.9 J/mol·deg.