Die Thermische Zersetzung von Hexamethylentetramin. I

Klipping, G.; Stranski, I. N.

doi:10.1002/zaac.19582970104

“…Data from Mansson et al (12) . (21) using the torsion effusion and the mass-loss effusion methods, as well as with those from Klipping and Stranski (22) who used quartz thread pendulum in the temperature range 293 K to 358 K and Hg-manometer in the temperature range 358 K to 553 K. The strain of a molecule H m (strain) is defined (1,2) as the difference between the experimental standard enthalpy of formation f H o m (g) and the calculated sum of the groupadditivity increments for the molecule. Using the classic Benson increments (1,2) (table 3) was about ±1-2 kJ · mol −1 .…”

Section: Resultsmentioning

confidence: 99%

Relationships among strain energies of mono- and poly-cyclic cyclohexanoid molecules and strain of their component rings

Verevkin

¹

2002

The Journal of Chemical Thermodynamics

View full text Add to dashboard Cite

“…Urotropin (U), besides its obvious medical importance (o)&o# -(&%#), distinguishes itself by forming almost perfect single crystals with very low dislocation density (`1 mm À2 ; DiPersio & Escaig, 1972) and a mosaic spread half-width of 7 very compact structure (packing coef®cient 0.74) that persists from 15 to 548 K, at which temperature sublimation occurs (Klipping & Stranski, 1958). U owes this behaviour to the rather weak (2.866 A Ê ) CÐHÁ Á ÁN hydrogen bonds that hold the molecules together.…”

Section: Introductionmentioning

confidence: 99%

“…The intermolecular correlations (Canut & Amoro Â s, 1958) between these rigid bodies lead to rather strong TDS in inter-Bragg space. On the other hand the situation is compounded by the tendency of U to start subliming at as low as 330 K (Birkedal, 1996) and, above 468 K, to chemically (Blaz Ïevic Â et al, 1979) and thermally (Klipping & Stranski, 1958) decompose.…”

Section: Introductionmentioning

confidence: 99%

“…It is a much studied classic capable of the most surprising applications. On the one hand the quasispherical molecule does not have a plastic phase but forms a very compact structure (packing coef®cient 0.74) that persists from 15 to 548 K, at which temperature sublimation occurs (Klipping & Stranski, 1958). U owes this behaviour to the rather weak (2.866 A Ê ) CÐHÁ Á ÁN hydrogen bonds that hold the molecules together.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Urotropin azelate: a rather unwilling co-crystal

Bonin

¹

,

Welberry

²

,

Hostettler

³

et al. 2003

Acta Crystallogr Sect B

View full text Add to dashboard Cite

Urotropin (U) and azelaic acid (AA) form 1:1 co-crystals (UA) that give rise to a rather complex diffraction pattern, the main features of which are diffuse rods and bands in addition to the Bragg re¯ections. UA is characterized by solvent inclusions, parasite phases, and high vacancy and dislocation densities. These defects compounded with the pronounced tendency of U to escape from the crystal edi®ce lead to at least seven exotic phase transitions (many of which barely manifest themselves in a differential scanning calorimetry trace). These involve different incommensurate phases and a peritectoid reaction in the recrystallization regime (T h b 0X6). The system may be understood as an OD (order±disorder) structure based on a layer with layer group Pcc2 and cell a o 9 4.7, b 9 26.1 and c 9 14.4 A Ê . At 338 K the layer stacking is random, but with decreasing temperature the build-up of an orthorhombic MDO (maximal degree of order) structure with cell a 1 = 2a o , b 1 = b, c 1 = c and space group Pcc2 is begun (at $301 K). The superposition structure of the OD system at T = 286 (1) K with space group Bmmb and cell a = 2a o , b = b and c = ca2 owes its cohesion to van der Waals interactions between the AA chains and to three types of hydrogen bonds of varied strength between UÐU and UÐAA. Before reaching completion, this MDO structure is transformed, at 282 K, into a monoclinic one with cell a m = Àa o c/4, b m = b, c m = À2a o ca2, space group P2 1 ac, spontaneous deformation $2, and ferroelastic domains. This transformation is achieved in two steps: ®rst a furtive triggering transition, which is not yet fully understood, and second an improper ferroelastic transition. At $233 K, the system reaches its ground state (cell a M = a m , b M = b, c M = c m and space group P2 1 ac) via an irreversible transition. The phase transitions below 338 K are described by a model based on the interaction of two thermally activated slip systems. The OD structure is described in terms of a three-dimensional Monte Carlo model that involves ®rst-and second-neighbour interactions along the a axis and ®rst-neighbour interactions along the b and c axes. This model includes random shifts of the chains along their axes and satisfactorily accounts for most features that are seen in the observed diffraction pattern.

show abstract

“…For the IR spectrum, see [146]. The vapor pressure between 20 and 280 C can be calculated from the formula log(p/kPa) ¼ À524.8/(T/K) þ 1.334 [147]. Flash point 250 C.…”

Section: N-methylpiperazinementioning

confidence: 99%

Amines, Aliphatic

Roose¹,

Eller

²

,

Henkes

³

et al. 2015

Ullmann's Encyclopedia of Industrial Chemistry

View full text Add to dashboard Cite

The article contains sections titled: 1. Introduction 2. General Chemical Properties 2.1. Salt Formation 2.2. Conversion to Carboxamides 2.3. Conversion to Sulfonamides 2.4. Reaction with Carbonyl Compounds 2.5. Reaction with Carbon Dioxide and Carbon Disulfide 2.6. Reaction with Epoxides 2.7. Alkylation 2.8. Formation of Isocyanates and Ureas 2.9. Reaction with Acrylonitrile 2.10. Formation of Isonitriles 2.11. Oxidation 2.12. Dealkylation 3. General Production Methods 3.1. Production from Alcohols 3.2. Production from Carbonyl Compounds 3.3. Production from Nitriles 3.4. Production from Alkyl Halides 3.5. Production from Nitro Compounds 3.6. Production from Olefins 3.7. Other Processes 4. Lower Alkylamines 4.1. Physical Properties 4.2. Storage and Transportation 4.3. Quality Specifications and Analysis 4.4. Production 4.5. Uses 4.6. Economic Aspects 5. Cycloalkylamines 6. Cyclic Amines 7. Fatty Amines 7.1. Properties 7.2. Production 7.3. Analysis and Quality Control 7.4. Uses 7.5. Economic Aspects 8. Diamines and Polyamines 8.1. Diamines Diaminoethane 8.1.1. Diaminopropanes 8.1.2. Higher Diamines 8.2. Oligoamines and Polyamines 8.2.1. Physical Properties 8.2.2. Chemical Properties 8.2.3. Production, Analysis, and Uses 9. Chiral Amines 10. Toxicology and Occupational Health 10.1. General Aspects 10.2. Toxicology of Specific Amines 10.2.1. Alkylamines, Cyclic Amines, and Polyamines 10.2.2. Fatty Amines

show abstract

Die Thermische Zersetzung von Hexamethylentetramin. I

Cited by 14 publications

References 2 publications

Relationships among strain energies of mono- and poly-cyclic cyclohexanoid molecules and strain of their component rings

Relationships among strain energies of mono- and poly-cyclic cyclohexanoid molecules and strain of their component rings

Urotropin azelate: a rather unwilling co-crystal

Amines, Aliphatic

Contact Info

Product

Resources

About