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1.
Victor A. Rozentsvet Nelly A. Korovina Valentina P. Ivanova Marianna G. Kuznetsova Sergei V. Kostjuk 《Journal of polymer science. Part A, Polymer chemistry》2013,51(15):3297-3307
The microstructure of poly(1,3‐pentadiene) synthesized by cationic polymerization of 1,3‐pentadiene with tBuCl/TiCl4 initiating system is analyzed using one‐dimensional‐ and two‐dimensional‐NMR spectroscopy. It is shown that unsaturated part of chain contains only homo and mixed dyads with trans?1,4‐, trans?1,2‐, and cis?1,2‐structures with regular and inverse (head‐to‐head or tail‐to‐tail) enchainment, whereas cis?1,4‐ and 3,4‐units are totally absent. The new quantitative method for the calculation of content of different structural units in poly(1,3‐pentadiene)s based on the comparison of methyl region of 13C NMR spectra of original and hydrogenated polymer is proposed. The signals of tert‐butyl head and chloromethyl end groups are identified in a structure of poly(1,3‐pentadiene) chain and the new approaches for the quantitative calculation of number‐average functionality at the α‐ and ω‐end are proposed. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 3297–3307 相似文献
2.
Hans R. Kricheldorf William E. Hull 《Journal of polymer science. Part A, Polymer chemistry》1978,16(9):2253-2264
Using sodium as the catalyst and benzoylchloride as cocatalyst, copolymerizations of γ-butyrolactam with ε-caprolactam and ω-capryllactam were carried out at 100°C. In a similar manner copolymerizations of ε-cparolactam, ω-capryllactam, and ε-laurinlactam were achieved at 150 and 250°C without a cocatalyst. The 90.5-MHz 13C-NMR spectra of all random copolyamides in fluorosulfonic acid show three or more CO signals that allow the ratio of homogeneous (A? A and B? B) to heterogeneous (A? B and B? A) amide groups to be determined. These results cleárly demonstrate that despite the reaction temperature or reactivity of the lactams the copolyamides do not contain long homogeneous blocks (An and Bn). The CO signals of the random copolyamides were assigned by comparison with the corresponding homopolyamides and alternating copolyamides. Solutions of the alternating copolyamide (-β-Ala-ε-Aca-)n, in fluorosulfonic acid were measured to determine whether the 13C chemical shifts and line widths are dependent on concentration. 相似文献
3.
Yoshiyuki Oishi Shoichi Nakata Mikio Kajiyama Masa-Aki Kakimoto Yoshio Imai 《Journal of polymer science. Part A, Polymer chemistry》1992,30(11):2357-2364
Random and block disiloxane-containing copolyamides were prepared through one- and two-step procedures, respectively, by the low temperature solution polycondensation in chloroform containing triethylamine hydrochloride starting from 1,3-bis(3-aminopropyl)tetramethyldisiloxane, an aromatic diamine [3,4'-diaminodiphenyl ether (ODA) or m-phenylenediamine], and isophthaloyl chloride. The random copolyamides exhibited composition-dependent single glass transition temperature (Tg), and gave transparent and tough films by solution casting or hot pressing. The ODA-based block copolyamides had two Tg's, and the solvent-cast transparent films exhibited microphase separated morphology. The block copolymers gave better quality films than the single-phase random copolymers. © 1992 John Wiley & Sons, Inc. 相似文献
4.
Gregory B. Kharas Alexander A. Delgado Karen Aco Louise M. Cardenas Miriam L. Lopez Akami D. Mazerat 《高分子科学杂志,A辑:纯化学与应用化学》2013,50(4):365-369
Electrophilic trisubstituted ethylenes, dihalogen ring-substituted ethyl 2-cyano-3-phenyl-2-propenoates, RPhCH?C(CN)CO2C2H5 (where R is 2,3-diCl, 2,4-diCl, 2,6-diCl, 3,4-diCl, 3,5-diCl, 2,3-diF, 2,4-diF, 2,5-diF, 2,6-diF, 3,4-diF, 3,5-diF) were prepared and copolymerized with styrene. The monomers were synthesized by the piperidine catalyzed Knoevenagel condensation of ring-substituted benzaldehydes and ethyl cyanoacetate, and characterized by CHN analysis, IR, 1H and 13C-NMR. All the ethylenes were copolymerized with styrene (M1) in solution with radical initiation (ABCN) at 70°C. The composition of the copolymers was calculated from nitrogen analysis, and the structures were analyzed by IR, 1H and 13C-NMR. The order of relative reactivity (1/r 1) for the monomers is 3,4-diCl (1.89) > 2,4-diCl (1.84) > 3,5-diCl (1.40) > 2,6-diCl (1.21) > 2,4-diF (1.16) > 2,3-diF (1.01) > 2,3-diCl (0.74) > 3,4-diF (0.52) > 2,6-diF (0.45) > 3,5-diF (0.44) > 2,5-diF (0.33). Relatively high Tg of the copolymers in comparison with that of polystyrene indicates a decrease in chain mobility of the copolymer due to the high dipolar character of the trisubstituted ethylene monomer unit. Decomposition of the copolymers in nitrogen occurred in two steps, first in the 250–500°C range with residue (2.6–5.0 wt%), which then decomposed in the 500–800°C range. 相似文献
5.
Gregory B. Kharas Katherine T. Flynn Benjamin L. Hill Mustafa R. Ishaq Darin A. Kopp Brittany G. Koroll 《高分子科学杂志,A辑:纯化学与应用化学》2013,50(2):95-99
Novel copolymers of trisubstituted ethylene monomers, halogen ring-disubstituted 2-phenyl-1,1-dicyanoethylenes, RC6H3CH= C(CN)2 (where R is 2,3-Cl2, 2,4-Cl2, 2,6-Cl2, 3,4-Cl2, 3,5-Cl2, 2-Cl-4-F, 2-Cl-6-F, 3-Cl-4-F) and 4-fluorostyrene were prepared at equimolar monomer feed composition by solution copolymerization in the presence of a radical initiator (ABCN) at 70°C. The composition of the copolymers was calculated from nitrogen analysis, and the structures were analyzed by IR, 1H and 13C-NMR. The order of relative reactivity (1/r 1) for the monomers is 2-Cl-4-F (2.42) > 3,4-Cl2(2.40) > 2,4-Cl2(1.97) > 2-Cl-6-F (1.86) > 3-Cl-4-F (1.68) > 2,3-Cl2 (0.89) > 3,5-Cl2 (0.70) > 2,6-Cl2 (0.47). High Tg of the copolymers, in comparison with that of poly(4-fluorostyrene) indicates a substantial decrease in chain mobility of the copolymer due to the high dipolar character of the trisubstituted ethylene monomer unit. Softening of the copolymers started in 194–216°C range. Decomposition of the copolymers in nitrogen occurred in two steps, first in the 290–400°C range with residue, which then decomposed in 400–800°C range. 相似文献
6.
Franz Brogli Wolfgang Eberbach Edwin Haselbach Edgar Heilbronner Volker Hornung David M. Lemal 《Helvetica chimica acta》1973,56(6):1933-1944
A comparative photoelectron spectroscopical investigation of the title compound ( 11 ) and its 3,4- and 7,8-dihydro derivatives ( 9 and 10 ) indicates that a considerable ‘through bond’ interaction exists between the π-orbitals in 11 . The PE. spectra of the 3,4-diaza-analogue of 10 and 11 , which contain a cis azo group in a four-membered ring, yield a splitting Δn (4-memb. ring) = 1.55–1.60 eV between the nitrogen lone-pair orbital energies. This value contrasts with those obtained for a three-membered ring analogue (3,3-dimethyldiazirine ( 5 ), Δn (3-memb. ring) = 3.55 eV) and for a five-membered ring analogue (2,3-diazanorbornene ( 7 ) Δn(5-memb. ring) = 3.10 eV). The sequence Δn (3-memb. ring) > Δn (4-memb. ring) Δn (5-memb. ring) is satisfyingly reproduced by MINDO/2- and EHT-calculations for the model systems with n = 3,4,5. A similar trend can be deduced from MINDO/2-calculations for cis-diimid where Δn becomes minimal for a N?N? H angle φ ≈ 100°, whereas Δn for the corresponding trans-structure goes through a maximum in this region. The experimental finding as well as the calculated results confirm the predictions made by Gimarc [15] who attributes the behaviour of Δn for cis-azo groups to a ‘through-bond’ interaction of the n +-orbital with a lowerlying N? N σ-orbital; this interaction becomes maximal for N?N? R angles of the size present in a fourmembered ring, e.g. in 12 or 13 . 相似文献
7.
Gregory B. Kharas Lisa M. Gennett Yolondria L. Harvey Elizabeth R. Jennings Denny Petropoulos Ovie C. Smith 《高分子科学杂志,A辑:纯化学与应用化学》2013,50(3):163-167
Novel trisubstituted ethylenes, chlorine ring-substituted 2-cyano-3-phenyl-2-propenamides, RC6H3CH?C(CN)CONH2 (where R is 2,3-dichloro, 2,4-dichloro, 2,6-dichloro, 3,4-dichloro, 2-chloro-5-nitro, 4-chloro-3-nitro, 5-chloro-2-nitro) were synthesized by potassium hydroxide catalyzed Knoevenagel condensation of ring-substituted benzaldehydes and cyanoacetamide and characterized by CHN elemental analysis, IR, 1H- and 13C-NMR. Novel copolymers of the ethylenes and styrene were prepared at equimolar monomer feed composition by solution in the presence of a radical initiation (AIBN) at 70°C. The composition of the copolymers was calculated from nitrogen analysis, and the structures were analyzed by IR, 1H- and 13C-NMR, GPC, DSC, and TGA. Thus, the order of relative reactivity (1/r1) and the tendency toward alternation of monomer units in the copolymer for the monomers is 2-Cl-5-NO2 (3.09) > 5-Cl-2-NO2 (1.88) > 4-Cl-3-NO2 (0.97) > 2,6-Cl2 (0.93) > 3,4-Cl2 (0.31) > 2,4-Cl2 (0.30) > 2,3-Cl2 (0.22). High Tg of the copolymers in comparison with that of polystyrene indicates a substantial decrease in chain mobility of the copolymer due to the high dipolar character of the trisubstituted ethylene monomer unit. Decomposition of the copolymers in nitrogen occurred in two steps, first in the 200–500°C range with residue (3.5–5.0 wt%), which then decomposed in the 500–800°C range. 相似文献
8.
Schiff bases of 1,3-dicarbonyl compounds with triamines and their Fe(III), Co(III), Ni(II) and Cu(II) complexes The preparation of new hexadentate ligands obtained by the reaction of cis, cis-1,3,5-triaminocyclohexane (tach) or 1,1,1-tris (aminomethyl)ethane (tame) with an 2-ethoxymethylidene-1,3-dicarbonyl compound as well as their Fe(III), Co(III), Ni(II) and Cu(II) complexes is reported. Fe(III) and Co(III) yield neutral complexes with an octahedral N3O3-coordination sphere, Ni(II) and Cu(II) complexes with a square-planar coordination-sphere. In the later complexes one of the bidentate branches of the ligand is not deprotonated and stays uncoordinated. 相似文献
9.
Robert N. Macdonald W. H. Sharkey 《Journal of polymer science. Part A, Polymer chemistry》1973,11(10):2519-2536
A series of polyamides was prepared by interfacial polymerization of diamines with 1,2,5-thiadiazole-3,4-dicarbonyl chloride. Polyamides from secondary cycloaliphatic diamines and aromatic diamines have high softening points, high glass transition temperatures, and good thermal stability. Secondary amines, in particular cycloaliphatic secondary amines, form very high molecular weight polyamides. The polyamide from trans-2,5-dimethylpiperazine and 1,2,5-thiadiazole-3,4-dicarbonyl chloride is soluble in chloroform and 1,1,2-trichloroethane and has been cast into films and spun into fibers from those solvents. Fibers of this polymer are strong and have very high work recovery from small strains. In addition, these fibers show good retention of strength and work recovery over a range of temperatures and humidities. 相似文献
10.
Preparation of dihydro-, tetrahydro- and hexahydro-chelidamic-acid derivatives. Three methods for the preparation of 4-oxo-2,6-piperidine-dicarboxylic acid ( 3 ) and derivatives, required as a synthon for betalaine pigments, were explored. The best method was found to be the catalytic hydrogenation of chclidamic acid ( 1 ) with 5% Rh/Alox in water under 2.7 atm. H2 for 33 h at 70° and subsequent esterification with methanol which gave 42% of cis, cis-4-hydroxy-2,6-piperidine- ( 7 ) and 10% of 2,6-cis-piperidine-dicarboxylic acid dimethyl ester ( 8 ), readily separable by chromatography. Oxidation of 7 with dimethylsulfoxide and a carbodiimide attached to a polymer afforded 90% of 4-oxo-2,6-cis-piperidine-dicarboxylic acid dimethyl ester ( 19 ). Other methods of oxydizing 7 to 19 were less successful. The electrochemical reduction of 1 followed by esterification with methanol led in a low yield to a mixture of 4-oxo-0-2,6-trans-piperidine-dicarboxylic acid dimethylester ( 24 ), its dimethyl acetal 25 and presumably trans-4-hydroxy-r-2, cis-6-piperidine-dicarboxylic acid dimethyl ester ( 26 ). Reaction of 4-oxo-hepta-2E, 5E-dienoic acid ( 35 ) with aqueous ammonia gave a 98% yield of a 3 : 2 mixture of cis- and trans-ammonium-4-oxo-2, 6-piperidine-dicarboxylate ( 39 and 40 ). The above mentioned catalytic hydrogenation method was also applied to N-ethyl-chelidamic acid ( 16 ) to give a 4:6 mixture of the N-ethyl derivatives 17 and 18 . Furthermore, a number of functional derivatives of 5 , of 19 , of 39 and of 40 were prepared. Oxidation of the hydroxy-diester 7 with dimethylsulfoxide and a carbodiimidc derivative in the presence of trifluoroacetic acid afforded 4-oxo-1,2,3,4-tetrahydro-2, 6-pyridine-dicarboxylic acid dimethyl ester ( 50 ). This ester was also obtained under the same conditions from thc keto-diester 19 . 相似文献
11.
Rodney L. Willer Robson F. Storey Christopher G. Campbell Steven W. Bunte Damon Parrish 《Journal of heterocyclic chemistry》2012,49(4):919-925
Reaction coordinate mapping was used to study the reaction of 3,4‐diamino[1,2,5]oxadiazole (3,4‐diaminofurazan) and 3,4‐diamino[1,2,5]thiadiazole with glyoxal. The thiadiazole was known to give a good yield of [1,2,5]thiadiazolo[3,4‐b]pyrazine, whereas the oxadiazole had not yielded, until now, [1,2,5]oxadiazolo[3,4‐b]pyrazine (or furazano[2,3‐b]pyrazine). The calculations suggested that the diols, 5,6‐dihydroxy‐4,5,6,7‐tetrahydro[1,2,5]oxadiazolo[3,4‐b]pyrazine and 5,6‐dihydroxy‐4,5,6,7‐tetrahydro[1,2,5]thiadiazolo[3,4‐b]pyrazine should be stable intermediates, and once formed, should provide a pathway to the target compounds via two dehydration steps, under forcing conditions. With this information in mind, the reactions of 3,4‐diamino[1,2,5]oxadiazole with glyoxal and pyruvic aldehyde were re‐examined. The reaction of 3,4‐diamino[1,2,5]oxadiazole with glyoxal and pyruvic aldehyde produced, under slightly basic conditions, a near quantitative yield of the expected initial products, 5,6‐dihydroxy‐4,5,6,7‐tetrahydro[1,2,5]oxadiazolo[3,4‐b]pyrazine and the 5‐methyl analog, respectively. The diols were easily isolated by lyophilizing the aqueous reaction mixture. The diols were pyrolized on silica gel at 160°C to give the desired [1,2,5]oxadiazolo[3,4‐b]pyrazine and the 5‐methyl analog. Both compounds were easily reduced to the corresponding 4,5,6,7‐tetrahydro‐derivative using sodium borohydride in THF/methanol. The [1,2,5]oxadiazolo[3,4‐b]pyrazine also displayed other interesting chemistry. 相似文献
12.
Hwa-Jin Jeong Masa-Aki Kakimoto Yoshio Imai 《Journal of polymer science. Part A, Polymer chemistry》1991,29(5):767-772
A new polymer-forming monomer, 3,4-bis(4-aminophenyl)-2,5-diphenylpyrrole, was synthesized in three steps starting from 4′-nitrodeoxybenzoin. Tetraphenylpyrrole-containing aromatic polyamides and copolyamides were prepared from the diamine with various aromatic diacid chlorides and from a mixture of the diamine and 4,4′-oxydianiline with terephthaloyl chloride, respectively. The resultant polymers had inherent viscosities in the 0.3–1.8 dL/g range and were generally soluble in various organic solvents including N,N-dimethylacetamide and m-cresol. They have glass transition temperatures in the range of 306–333°C and showed no weight loss below 380°C in both air and nitrogen atmospheres. 相似文献
13.
Rodney L. Willer Robson F. Storey William L. Jarrett Damon Parrish 《Journal of heterocyclic chemistry》2012,49(3):705-709
The unusual 12‐membered ring compound, octahydro‐5H,12H‐4,11‐methano‐1H,7H‐bis[1,2,5]oxadiazolo[3,4‐d:3′,4′‐j][1,7,3,9]dioxadiazacyclododecine is obtained from the acid catalyzed reaction of 3‐amino‐4‐hydroxymethylfurazan with formaldehyde instead of the expected methylene‐bridged compound, 4,4′‐methylenebis[4,5‐dihydro‐7H‐[1,2,5]oxadiazolo[3,4‐d][1,3]oxazine]. The compound crystallizes in Tetragonal, P43212, a = 6.4141(4) Å, b = 6.4141(4) Å, c = 26.525(3) Å, α = 90°, β = 90°, γ = 90°, V = 1091.27(16) Å3, Z = 4, dcalc = 1.614 Mg/m3. 相似文献
14.
Klenov M. S. Ratnikov M. O. Churakov A. M. Solkan V. N. Strelenko Yu. A. Tartakovsky V. A. 《Russian Chemical Bulletin》2011,60(3):536-547
Methods for the synthesis of [1,2,5]oxadiazolo[3,4-c]cinnoline 5-oxides, which include the reaction of 3-nitramino-4-(R-phenyl)furazans or their O-methyl derivatives with electrophilic agents, have been developed. Unsubstituted [1,2,5]oxadiazolo[3,4-c]cinnoline 5-oxide was synthesized from 3-nitramino-4-phenylfurazan upon the action of phosphorus anhydride or oleum, as well
as from O-methyl derivative of 3-nitramino-4-phenylfurazan upon the action of H2SO4, MeSO3H, CF3CO2H and BF3·Et2O, while 6-, 7-, 8-, and 9-nitro-substituted [1,2,5]oxadiazolo[3,4-c]cinnoline 5-oxides — from the corresponding 3-nitramino-4-(nitrophenyl)furazans upon the action of the H2SO4-HNO3 nitrating mixture. A suggestion has been made that an oxodiazonium ion is formed in these reactions from nitramines or their
O-methyl derivatives upon the action of electrophilic agents, which is further involved into the intra-molecular reaction of
electrophilic aromatic substitution (S
EAr) with the aryl group. The structure of [1,2,5]oxadiazolo[3,4-c]cinnoline 5-N-oxides was confirmed by 1H, 13C, and 14N NMR spectra. Theoretical studies by the B3LYP/6-311G(d,p) method of combined molecular system (O-methylated 3-nitramino-4-phenylfurazan + [H3SO4]+) resulted in calculation of thermodynamic parameters of the sequence of cascade elementary reactions leading to the formation
of [1,2,5]oxadiazolo[3,4-c]cinnoline 5-oxide. 相似文献
15.
Steven Grossman Andrzej Stolarczyk Otto Vogl 《Monatshefte für Chemie / Chemical Monthly》1981,112(11):1279-1296
Head to head polypropylene was prepared by catalytic hydrogenation of eithercis-1,4-poly(2,3-dimethylbutadiene) ortrans-1,4-poly(2,3-dimethylbutadiene) with cobalt 2-ethylhexanoate/triethylaluminium as the hydrogenation catalyst in decahydronaphthalene solution. The hydrogenation occurred predominantly bycis hydrogen addition, but was not stereospecific. The samples of head to head polypropylene were characterized by IR and NMR, particularly by13C-NMR spectroscopy. The polymers were amorphous and exhibited glass transition temperatures about 20°C lower than that of head to tail poly-propylene; the glass transition temperatures were measured by DSC and varied somewhat from sample to sample (sufficiently high molecular weight) according to their stereochemistry. TheT
gvalues were confirmed by Rheovibron measurements. The thermal stability of head to head polypropylene is not significantly different from that of either atactic or isotactic head to tail polypropylene.Part XVI:Grossman S., Yamada A., Vogl O., J. Macromol. Sci.-Chem.A 16, 897 (1981). 相似文献
16.
A. Kakanejadifard A. Saniei F. Delfani M. Farnia G. R. Najafi 《Journal of heterocyclic chemistry》2007,44(3):717-718
17.
Comprehensive structural characterization of polyisoprene synthesized via cationic mechanism
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Victor A. Rozentsvet Nelly A. Korovina Olesya A. Stotskaya Marianna G. Kuznetsova Frederic Peruch Sergei V. Kostjuk 《Journal of polymer science. Part A, Polymer chemistry》2016,54(15):2430-2442
The microstructure of polyisoprene synthesized with tBuCl/TiCl4 initiating system is investigated using 1D and 2D (HSQC and HMBC) NMR spectroscopy. It is found that trans‐1,4‐units with regular (head‐to‐tail) and inverse (tail‐to‐tail) and (head‐to‐head) enchainments are predominant structures of unsaturated part of polymer chain, while 1,2‐ and 3,4‐units are presented in minor amounts. The new methodology for the quantitative calculation of the content of different structural units in polyisoprene chain including both types of inverse trans‐1,4‐addition (tail‐to‐tail and head‐to‐head) is proposed. It is shown that head groups consist of tert‐butyl group connected to trans‐1,4‐unit of polyisoprene chain. In addition, two types of chlorine‐containing end groups are found (trans‐4,1‐Cl and 4,3‐Cl), while conjugated double bonds at the chain end are totally absent. The methodology for the calculation of number‐average functionality by tert‐butyl head and chlorine end groups, respectively, is developed. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 2430–2442 相似文献
18.
Gregory B. Kharas Emi Hanawa Benjamin L. Hill Katherine T. Flynn Lauren N. Furlan Brandon Holtrup 《高分子科学杂志,A辑:纯化学与应用化学》2013,50(2):91-94
Novel copolymers of trisubstituted ethylene monomers, ring-substituted 2-phenyl-1,1-dicyanoethylenes, RC6H3CH?C(CN)2 (where R is 2,3-(CH3O)2, 2,4-(CH3O)2, 2,5-(CH3O)2, 2,6-(CH3O)2, 3,4-(CH3O)2, and 3,5-(CH3O)2 and 4-fluorostyrene were prepared at equimolar monomer feed composition by solution copolymerization in the presence of a radical initiator (ABCN) at 70°C. The composition of the copolymers was calculated from nitrogen analysis, and the structures were analyzed by IR, 1H and 13C-NMR. The order of relative reactivity (1/r 1) for the monomers is 2,6-(CH3O)2(2.8) > 2,5-(CH3O)2(2.5) > 2,3-(CH3O)2 (2.1) > 3,5-(CH3O)2 (1.8) > 3,4-(CH3O)2 (0.9) > 2,4-(CH3O)2 (0.7). High Tg of the copolymers, in comparison with that of poly(4-fluorostyrene) indicates a substantial decrease in chain mobility of the copolymer due to the high dipolar character of the trisubstituted ethylene monomer unit. Decomposition of the copolymers in nitrogen occurred in two steps, first in the 250–400°C range with residue, which then decomposition in 400–800°C range. 相似文献
19.
Frank R. Prince Eli M. Pearce Robert J. Fredericks 《Journal of polymer science. Part A, Polymer chemistry》1970,8(12):3533-3541
It was desired to determine the effect of geometric configuration on the ability of 4-aminomethylcyclohexanecarboxylic acid (AMCC) to “isomorphously” replace ε-aminocaproic acid residues in nylon 6. However, we found that cis-AMCC isomerized to the more thermodynamically stable trans isomer during copolymerization with caprolactam (CL) and also during homopolymerization. A 20/80 cis/trans ratio of AMCC residues was found in the 50:50 copolyamides regardless of whether a high-cis (72/28) or high-trans (15/85) AMCC was used. Powder x-ray diagrams showed similar interplanar spacings for the copolyamides made from both high-cis and high-trans AMCC. The x-ray study also showed that the nylon 6 lattice can accommodate less than 30 mole-% AMCC residues before a new structure appears. DTA and TGA data of the CL:AMCC copolyamide showed that AMCC raised the melting point, Tg, Tc, and stability of nylon 6. 相似文献
20.
The o-diamine, 3,4-diamino-1,2,5-thiadiazole ( 2 ), was synthesized from 3,4-dichloro-1,2,5-thiadiazole ( 3 ) hy three methods. Aqueous glyoxal cyclized 2 into [1,2,5]thiadiazolo[3,4–6]-pyrazine ( 14 ). 3,4-Dichloro-1,2,5-thiadiazole 1,1-dioxide ( 18 ) reaeted with 2 to give 1,3-dihydro-bis[1,2,5]thiadiazolo[3,4-b:3′,4′-e]pyrazine 2,2-dioxide ( 19 ). The reaction of 2 with selenium oxyehloride led to [1,2,5]selenadiazolo[3,4-c] [1,2,5]thiadiazole ( 12 ). Ring closure of 2,3-diaminoquinoxaline ( 4 ) with thionyl chloride or selenium oxychloride gave [1,2,5]thiadiazolo-[3,4-b]quinoxaline ( 21 ) and [1,2,5]selenadiazolo[3,4-b]quinoxaline ( 22 ), respectively. Sulfurous acid reduced 21 to the 4,9-dihydro derivative 23 , which was reoxidized to 21 with chloranil. Aqueous hase hydrolyzed 21 to 4 via the hydrated intermediate 24 . Aqueous glyoxal cyclized 4 to the covalent hydrate of pyrazino[2,3-b]quinoxaline ( 26 ), 27 , which was dehydrated to 26 . Compound 26 underwent rapid addition of two alcohols in a process analogous to covalent hydration. 相似文献