Thermal decomposition of zinc hydroxy azide

The isothermal decomposition of zinc hydroxy azides, Zn(OH)_2-x(N₃)_x: follows deceleratory kinetics throughout the temperature range studied. The initial part of the decomposition fits into unimolecular decay law, log (1-a) = -kt. The contracting volume law satisfactorily describes the data at higher degrees of decomposition. The maximum value ofa upto which the slow decomposition could be recorded was 0.75. The aged form of zinc hydroxy azide decomposes with much lower rates and slightly different topochemical characteristics. The decrease in the rate of decomposition on ageing has been attributed to the formation of carbonate on the surface of the compound during storage. The change in topochemical behaviour is traced to the reported layer structure of zinc hydroxy azide. The effect of pre-heating on subsequent thermal decomposition has also been discussed.     

Photolysis of unsubstituted and p-methoxycarbonyl substituted 2-methyl-1-phenylprop-2-en-1-one copolymers in solution

A new monomer, methyl 4-(2-methyl-1-oxoprop-2-en-1-yl)benzoate (p-(methoxycarbonyl)phenyl isopropenyl ketone, MeOCO-PIPK), was synthesized and copolymerized with styrene and methyl methacrylate (MMA). The copolymers of MeOCO-PIPK and 2-methyl-1-phenylprop-2-en-1-one (phenyl isopropenyl ketone, PIPK) with styrene and MMA were photolyzed by deep-, mid- and near-UV light in dilute solution; and the quantum yields of scission, ϕ_g, and the UV absorption spectra were measured. The p-methoxycarbonyl substitution increased the molar extinction coefficients of the ketone monomer units extensively, but slightly lowered the ϕ_g values in styrene and MMA copolymers. This is expected to increase the net sensitivity of solid films of the polymers. The ϕ_g was found independent of the wavelength, despite the concurrent absorption by styrene units in the styrene copolymers. Larger ϕ_g values were obtained for the MMA copolymers than the corresponding styrene copolymers. Solvents with larger dielectric constants gave larger ϕ_g for the copolymer of MMA with PIPK; but when the dielectric constants were similar, lower ϕ_g values were observed in the solvents with more easily abstractable hydrogens. A large bleaching effect was seen in MMA copolymers, which should make possible the formation of resist patterns with steep profiles when used in photolithography. © 1996 John Wiley & Sons, Inc.     

Photolysis of dimethyldioxirane

Phosphorescence of methyl acetate formed by isomerization of electron-excited dimethyldioxirane is observed upon excitation at the wavelength of the absorption band of dimethyldioxirane in acetone at 77 K. The quantum yield of the photodecomposition of dimethyldioxirane at 296 K is equal to 13.1±0.7 mol Einstein⁻¹. The high quantum yield of photolysis is evidence for the chain mechanism of decomposition of dimethyldioxirane. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 938–941, May, 1997.     

Photolysis of thallium azide

Preliminary treatment of TlN₃(A) with light (λ = 365 nm, I > 1 × 10¹⁴ quantum cm⁻² s⁻¹) in a vacuum (1 × 10⁻⁵ Pa) at 293 K led to the formation of a new long-wave region of spectral sensitivity. The products of photolysis of TlN₃(A) thallium and nitrogen formed in the stoichiometric ratio on the sample surface. The topography and kinetics of thallium accumulation were determined, and the effective rate constants for photolysis evaluated. Measurements of the contact voltage, current-voltage characteristics, and photocurrent showed that the photolysis of thallium azide resulted in the formation of TlN₃(A)-Tl (photolysis product) microheterogeneous systems. A model of photolysis of TlN₃(A) was suggested. According to this model, photolysis included the generation, recombination, and redistribution of nonequilibrium charge carriers in the contact field and the formation of the end products of photolysis. The limiting stage of photolysis of TlN₃(A) was the diffusion of interstitial thallium cations toward the neutral (T _n Tl _m )⁰ center. Original Russian Text ? E.P. Surovoi, L.I. Shurygina, L.N. Bugerko, N.V. Borisova, 2009, published in Zhurnal Fizicheskoi Khimii, 2009, Vol. 83, No. 4, pp. 784–790.     

Studies on the reactions of fluoroalkanesulfonyl azide with aromatic compounds

The thermal decomposition reactions of fluoroalkanesulfonyl azides R_fSO₂N₃ (1) in the presence of various substituted benzene X_nC₆H_6−n [X: CH₃ (n=1, 2, 4, 6), OCH₃ (n=1, 2), C₆H₅CH₂ (n=1), F, Cl, Br] were studied in detail. The N-aryl fluoroalkanesulfonyl amides [R_fSO₂NHC₆H_5−nX_n] were produced as the major products. The ortho/para ratio resembled that of an electrophilic aromatic substituted reaction. An ionic π- or σ-complex was postulated as the intermediate for these reactions.     

High energy binders: glycidyl azide and allyl azide polymer

Hydroxy-terminated azido polymers such as poly(glycidyl azide), poly bis(azidomethyl oxetane) and poly(azidomethyl methyloxetane) have been investigated in the past in propellent formulations and as fuels in rocket technology. The high energy released upon the decomposition of the azido group is responsible for their specialized application as high-energy binders. The present paper describes the synthesis and characterization of new low molecular mass azido polymer i.e. poly(allyl azide). The curing reaction was carried out by using 1,3-cyclic dipolar addition reaction. The dipolarophiles, such as dimethylene glycol dimethacrylate (EGDMA) and addition polyimides (bismaleimides, bisnadimides and bisitaconimides) were used for curing of azido polymers. The curing reaction was monitored by FT-IR and differential scanning calorimetry. Curing was carried out at 40°C for 16 h (EGDMA) or 2 days (bismaleimide) and then at 60°C by using different phr of dipolarophiles. The heat of exothermic transition, due to decomposition of azide groups and thermal polymerization of addition polyimides, was very high and an improvement in thermal stability of cured resins was observed.     

Continuous,on-demand generation and separation of diphenylphosphoryl azide

Diphenylphosphorylazide (DPPA) has been synthesized in microfluidics with near-100% yield in sub-3 minute residence time, affordably, and with a process design that minimizes hazards associated with hydrazoic acid (HN₃) production. A pilot-plant scale continuous process for the on-demand synthesis of diphenylphosphoryl azide (DPPA) that can readily be integrated with subsequent transformations was designed, built, and validated. Using Corning's Low Flow reactor system coupled to a membrane separator and in-line Fourier Transform Infrared (FTIR), DPPA was safely produced at a rate of 1?mol/hr as a 2.0?M anhydrous toluene stream. Continuous FTIR was able to reliably monitor product quality, purity and concentration, showcasing the ease and utility of this continuous flow process for manufacturing common, safe pharmaceutical precursors.     

Room‐temperature RAFT copolymerization of 2‐chloroallyl azide with methyl acrylate and versatile applications of the azide copolymers

A new vinyl azide monomer, 2‐chlorallyl azide (CAA), has been synthesized from commercially available reagent in one step. The reversible addition fragmentation chain transfer (RAFT) copolymerization of CAA with methyl acrylate (MA) was carried out at room temperature using a redox initiator, benzoyl peroxide (BPO)/N,N‐dimethylaniline (DMA), in the presence of benzyl 1H‐imidazole‐1‐carbodithioate (BICDT). The polymerization results showed that the process bears the characteristics of controlled/living radical polymerizations, such as the molecular weight increasing linearly with the monomer conversion, the molecular weight distribution being narrow, and a linear relationship existing between ln([M]₀/[M]) and the polymerization time. Chain extension polymerization was performed successfully to prepare block copolymer. Furthermore, the azide copolymers were functionalized by Cu^I‐catalyzed “click” reaction with alkyne‐containing poly(ethylene glycol) (PEG) to yield graft copolymers with hydrophilic PEG side chains. Surface modification of the glass sheet was successfully achieved via the crosslinking reaction of the azide copolymer under UV irradiation at ambient temperature. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1348–1356, 2010     

Reaction of dihydropyran with phenyl azide

The reaction of dihydropyran with phenyl azide leads to the formation of N-phenyliminotetrahydropyran.     

Photolysis of zinc azide in the solid state

The photolysis of anhydrous zinc azide prepared by (1) dehydration of Zn(N₃)₂·2H₂O and (2) precipitation by acetone from aqueous solution, under the action of high pressure mercury arc is reported here. The pressure of nitrogen developed during photolysis under steady-state conditions at constant intensity is a linear function of t^1/2 in both the samples. The rate of photolysis is a linear function of intensity at constant temperature. A detailed analysis of the dark rate suggests that the dependence on t^1/2 should be due to the diffusion of nitrogen from the reaction site to the surface of the solid azide. An appropriate mathematical analysis is presented. The linear dependence of the rate of photolysis on the intensity of irradiation is interpreted in terms of the reaction of a trapped exciton with an adjacent azide ion. Absence of any detectable photoconduction in the wavelength range of the irradiating radiation suggests that excitons are the most probable reactive species. The sample of zinc azide obtained by the first method decomposes faster than the other under identical conditions, and has a slightly lower energy of activation of 1.4 kcal/mole compared to 1.75 kcal/mole for the second. These differences are discussed in terms of the defect concentrations of the two azide samples.     

Crystallographic report: Tribenzyltin(IV) azide

Tribenzyltin azide adopts a polymeric structure with 1,3‐bridging azide groups; the tin exhibits an almost regular trigonal bipyramidal trans‐N₂SnC₃ environment. Copyright © 2003 John Wiley & Sons, Ltd.     

Vibrational frequencies and structural determination of cyanogen azide

The vibrational frequencies and corresponding normal mode assignments of cyanogen azide are examined theoretically using the Gaussian03 set of quantum chemistry codes. All normal modes were successfully assigned to one of seven types of motion predicted by a group theoretical analysis (NN stretch, NN stretch, N–C stretch, CN stretch, NNN bend, NN–C bend, and N–CN bend). Theoretical infrared and Raman intensities are reported. The molecular orbitals and bonding of cyanogen azide are examined.     

ViscosityB-Coefficient of ammonium azide and the enthalpy of formation of the azide anion

Recent determination of the standard enthalpy of formation of the ammonium azide _f H ^O (NH N ₃,c) and the assignment of the viscosity B-coefficient for the azide anion, B(N ₃ ^– ,aq), in aqueous solution enable us to estimate the standard enthalpy of formation of the gaseous azide anion, _f H ^O (N ₃ ^–,g , — a thermochemical magnitude in some dispute — to be 192 kJ-mol^–1.     

Synthesis of poly(phenyltrifluoroethoxyphosphazene) by direct reaction of trimethylsilyl azide with bis(2,2,2-trifluoroethyl) phenylphosphonite

The reaction between bis(2,2,2-trifluoroethyl) phenylphosphonite and trimethylsilyl azide at temperatures from 70 to 120°C provides a mixture of bis(2,2,2-trifluoroethoxy)phenylN-(trimethylsilyl) phosphoranimine and poly(phenyl-2,2,2-trifluoroethoxyphosphazene). The polymer is probably formed by phosphine azide intermediates because the phosphor-animine is thermally stable up to 200°C. The polyphosphazene is an amorphous stereo-random polymer with a glass transition temperature at ?31°C.     

Reaction of phenyl azide with N,N-dimethyl-aminomethylenephenylphosphines

Phenyl azide reacts with N,N-dimethylamino-P-phenylmethylenephosphines with cleavage of the phosphoruscarbon double bond and formation of the dimer of diiminophosphorane and amidines.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 10, pp. 2381–2382, October, 1989.     

Photolysis of 3-nitrophenyl azide: Trapping the reactive intermediates

Irradiation of 3-nitrophenyl azide gives four trappable intermediates; the singlet nitrene, two isomeric dehydroazepines, and the triplet nitrene.     

Improvement of the fluorescence quantum yield of triphenylene by the rotational effect of 4-(trimethylsilyl)phenyl groups

The fluorescence quantum yield of triphenylene is low because the transition moment between the HOMOs and the LUMOs is negligibly small. To improve the fluorescence quantum yield, break of the symmetrical structure of triphenylene is necessary. We found that the rotational effect of the 4-(trimethylsilyl)phenyl groups of 2,3,6,7,10,11-hexakis[4-(trimethylsilyl)phenyl]triphenylene is effective to break the symmetry in spite of the symmetrical structure, leading to improvement of the fluorescence quantum yield.     

A new insertion reaction of phenyl isocyanate

A new reaction of the insertion of phenyl isocyanate into the C-C bond of P-containing zwitterions based on 2-cyanoacrylates was found. A probable mechanism of this reaction has been discussed.The X-ray structural study of compound3b was carried out by Yu. T. Struchkov and O. V. Shishkin, and its results will be published separately.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 186–187, January, 1995.