Properties of Isophorone

The irritancy properties of isophorone have also been observed in humans exposed occupationally to isophorone. In an industrial hygiene survey, Kominsky (1981) reported that the eye and nose irritation complained of by a screen printer could have been caused by 4-minute exposure to 25.7 ppm isophorone, which was measured in the personal breathing zone while the worker was washing a screen. Lee and Frederick (1981) found that eye, respiratory, and skin irritation were among the complaints of 27/35 workers in a printing plant where isophorone and other solvents (xylene, methylene chloride, and toluene) were used. On the day of measurement, two of the screen printers were found to be exposed to 8-hour TWA concentrations of isophorone of 0.7 and 14 ppm, but it was not clear whether these two individuals were among the workers complaining of irritation. The odor threshold for isophorone in air has been reported to be 0.2 ppm (v/v) (Amoore and Hautala 1983). 

The physical and chemical properties of isophorone are presented in Table 3-2. 

The various reaction rate properties of the different solvents influence the design of a catalytic reactor. Eor example, for a specific catalyst bed design, an effluent stream containing a preponderance of monohydric alcohols, aromatic hydrocarbons, or propjiene requires a lower catalyst operating temperature than that required for solvents such as isophorone and short-chain acetates. 

The type of catalyst strongly influences the enantioselectivity of heterogeneous catalytic hydrogenations (1). In the enantioselective saturation of the C=C bond of isophorone over (-)-dihydroapovincaminic acid ethyl ester ((-)-DHVIN) modified Pd catalysts (scheme 1) the optical purity strongly depended on the type and properties of the support used (2, 3, 4). 

Isophorone diamine (IPDA), 10 395 14 588 cis, Irares-Isophoronediamine physical properties of, 2 500t Isophorone dienamine-acrylonitrile reaction, 13 438... 

Hydroxy-terminated polyester (HTPS) is made from diethylene glycol and adipic acid, and hydroxy-terminated polyether (HTPE) is made from propylene glycol. Hydroxy-terminated polyacetylene (HTPA) is synthesized from butynediol and paraformaldehyde and is characterized by acetylenic triple bonds. The terminal OH groups of these polymers are cured with isophorone diisocyanate. Table 4.3 shows the chemical properties of typical polymers and prepolymers used in composite propellants and explosives.E4 All of these polymers are inert, but, with the exception of HTPB, contain relatively high oxygen contents in their molecular structures. 

In order to avoid the use of lead compounds on environmental grounds, lithium fluoride (liF) has been chosen to obtain super-rate burning of nitramine composite propellants.P7281 Typical chemical compositions of HMX composite propellants-with and without liF are shown in Table 7.4. The non-catalyzed HMX propellant is used as a reference pyrolant to evaluate the effect of super-rate burning. The HMX particles are of finely divided, crystalline (3-HMX with a bimodal size distribution. Hydroxy-terminated polyether (HTPE) is used as a binder, the OH groups of which are cured with isophorone diisocyanate. The chemical properties of the HTPE binder are summarized in Table 7.5. 

Thus, structure-activity relationships developed to estimate levels in biological media based on the partitioning properties of a chemical may not provide accurate information for isophorone. Furthermore, only one bioaccumulation study was available. In this study, which indicated a low potential for bioaccumulation, fish were exposed to isophorone in water rather than in food. From these data, it appears that food chain bioaccumulation may be occurring, and a clearer understanding of the potential for this would aid in determining how levels in the environment affect the food chain and potentially impact on human exposure levels. 

Private Consultant, Albany, NY Dr. Bhola N. Banerjee, Private Consultant, Potomac, MD and Dr. Judith S. Beilin, Private Consultant, Washington, DC These experts collectively have knowledge of isophorone s physical and chemical properties, toxicokinetics, key health end points, mechanisms of action, human and animal exposure, and quantification of risk to humans. All reviewers were selected in conformity with the conditions for peer review specified in the Superfund Amendments and Reauthorization Act of 1986, Section 110. 

TABLE 2. Physical properties of polyhexamethyleneguanidine derivatives prepared by reacting the Step 1 pre-polymer with isophorone diisocyanate. 

Many papers and patents deal with incorporation of additives in the poly-(urethane-seq-butadiene)s to increase the condensation efficiency, to improve the processing, or to improve the properties of solid propellants. A processing aid, trialkylamine 2201 and also tetracycline 221), was shown to reduce the viscosity and increase the pot life of hydroxytelechelic polybutadiene/polyisocyanate systems. It has been shown that the cure of isophorone diisocyanate and hydroxytelechelic polybutadienes was not affected by the addition of the ammonium perchlorate propellant 222). Special modification of HTPBs have been referred to in Refs. 223 236>. 

Good catalytic properties have also been reported by Teissier and Kervenal [34] for the synthesis of isophorone on an hydrotalcite first calcined then rehydrated. The superiority of the rehydrated solid in the experiment is apparent from the observation that the reaction performed in a batch reactor at 473 K reaches about... 

Mg-Al mixed oxides obtained by thermal decomposition of anionic clays of hydrotalcite structure, present acidic or basic surface properties depending on their chemical composition [1]. These materials contain the metal components in close interaction thereby promoting bifunctional reactions that are catalyzed by Bronsted base-Lewis acid pairs. Among others, hydrotalcite-derived mixed oxides promote aldol condensations [2], alkylations [3] and alcohol eliminations reactions [1]. In particular, we have reported that Mg-Al mixed oxides efficiently catalyze the gas-phase self-condensation of acetone to a,P-unsaturated ketones such as mesityl oxides and isophorone [4]. Unfortunately, in coupling reactions like aldol condensations, basic catalysts are often deactivated either by the presence of byproducts such as water in the gas phase or by coke build up through secondary side reactions. Deactivation has traditionally limited the potential of solid basic catalysts to replace environmentally problematic and corrosive liquid bases. However, few works in the literature deal with the deactivation of solid bases under reaction conditions. Studies relating the concerted and sequential pathways required in the deactivation mechanism with the acid-base properties of the catalyst surface are specially lacking. 

Farkas, G, Hegedus, L., Tungler, A., Mathe, T., Figueiredo, J.L., Freitas, M. (2000) Effect of carbon support properties on enantioselective hydrogenation of isophorone over palladium catalysts modified with (-)-dihydroapovincaminic acid ethyl ester, J. Mol Catal A Chem. 153, 215-219. 

A.G. Supri, and H. Ismail, The effect of isophorone diisocyanate-polyhydroxyl groups modified water hyacinth fibers (Eichhornia crassiper) on properties of low density polyethylene/ acrylonitrile butadiene styrene (LDPE/ABS) composites. Polym. Plast. Technol. Eng. 50(2), 113-120 (2011). 

PU based on the use of pristine castor oil were reviewed in 2010 [9, 10], including preparation and properties of an interpenetrating network with other polymers. Recent additions to this topic include work by Larock and co-workers [13, 14] on waterborne PU and their silica composites a kinetic study of the reaction of castor oil with 4,4 -methylene diphenyl diisocyanate to produce an elastomeric matrix [15] the rheology of waterborne PU dispersions for coating applications, prepared with castor oil and isophorone diisocyanate (IPDI) [16] (Scheme 3.7) and the synthesis and characterisation of gelled materials arising from the reaction of isocyanate-bearing chitin or chitosan with castor oil [17]. 

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