Sodium diisocyanate

There are several possible routes whereby such responses can be affected. First, there is a neural response, as evidenced by the analogous symptoms of the cardiac and pulmonary chemoreflexes. Second, mediators released from the inflammatory cells in the lungs are carried by the blood directly to the heart. Of note, C3a and C5a which are released during anaphylaxis activate cardiac, but not limg mast cells (62). Third, antigens may penetrate the airway and alveolar epithelium and enter into the vasculature and directly interact with cardiac mast cells and basophils. This latter pathway is likely important when small molecules, such as sodium diisocyanate, are inhaled, as these molecules form albumin-isocyanate conjugates that may be related to the induction of toluene diisocyanate hypersensitivity (69). 

Methylene dianiline is normally a very reactive diamine in the presence of diisocyanates. However, a sodium chloride complex that is relatively unreactive at room temperature is commercially available. When the complex is heated to 21°C, it activates to quickly cure the urethane [76]. 

Materials and Purification. Chemicals were purchased from Aldrich chemical company and used as received unless otherwise noted 1,1,1,3,3,3-hexamethyl disilazane, ethylene glycol, triphosgene, poly(ethylene oxide) (MW = 600), poly(tetramethylene oxide) (MW = 1000), poly(caprolactonediol) (MW = 530), toluene diisocyanate (TDI), anhydrous ethanol (Barker Analyzed), L-lysine monohydride (Sigma) and methylene bis-4-phenyl isocyanate (MDI) (Kodak). Ethyl ether (Barker Analyzer), triethylamine and dimethyl acetamide were respectively dried with sodium, calcium hydride and barium oxide overnight, and then distilled. Thionyl chloride and diethylphosphite were distilled before use. 

Conditions for the safe preparation of the diisocyanate from adipoyl chloride and sodium azide in acetonitrile-toluene mixtures were established. 

Manetz, T.C., Pettit, D.A. and Meade, B.J., The determination of draining lymph node cell cytokine mRNA levels in BALB/c mice following dermal sodium lauryl sulfate, di-nitrofluorobenzene, and toluene diisocyanate exposure. Toxicol. Appl. Pharm., 171, 174, 2001. 

Sodium hydride Sodium hydrosulfite Sulfur chlorides Sulfuric acid Sulfuryl chloride Tetraethyl lead Tetramethyl lead Thionyl chloride Titanium tetrachloride Toluene diisocyanate Trichlorosilane Triethylaluminum Triethylborane Triisobutylaluminum Trimethylaluminum Trimethylchlorosilane Tripropyl aluminum Vanadium tetrachloride Vinyl trichlorosilane Zirconium tetrachloride... 

Isocyanates are capable of co-reacting to form dimers, oligomers and polymers. For example, aromatic isocyanates will readily dimerize when heated, although the presence of a substituent ortho to the -NCO group reduces this tendency. For example, toluene diisocyanate (TDI) is less susceptible to dimer formation than diphenylmethane diisocyanate (MDI). The dimerization reaction is reversible, with dissociation being complete above 200 °C. It is unusual for aliphatic isocyanates to form dimers, but they will readily form trimers, as do aromatic isocyanates. The polymerization of aromatic isocyanates is known, but requires the use of metallic sodium in DMF. 

The average prices of commercial quantities in cents per pound are given in Table 13.1. Six chemicals are over 1.00/lb hexamethylenediamine (59), methylene diphenyl diisocyanate (68), toluene diisocyanate (78), phosphorus (86), 1,4-butanediol (89), and potassium hydroxide (90). In 1992 only three chemicals, and in 1988 only two chemicals, were over 1.00/lb. The cheapest of the second 50 chemicals is tall oil, with sodium sulfate close. The average price for all the second 50 chemicals is 0.55/lb. 

Dimethisterone (see also Progestins Sequential oral eontraeeptives) Dimethoxane 3,3 -Dimethoxy benzidine 3,3 -Dimethoxybenzidine-4,4 -diisocyanate para-Dimethylaminoazobenzene / ara-Dimethylaminoazobenzenediazo sodium sulfonate tra 5-2-[(Dimethylamino)methylimino]-5-[2-(5-nitro-2-furyl)-vinyl]-l,3,4-oxadiazole... 

Sulfo group-containing poly(amide imide) semipermeable membrane 35 from trimellitic anhydride sodium 3,5-dicarboxybenzenesulfonate, and 4,4 -diphenyl-methane diisocyanate have been prepared 90>. A 110 p-thick membrane gave water permeation 5601/m2 day and salt rejection 99.0% (0.5% aqueous NaCl solution, 25 °C, 42 kg/cm2), while a trimellitic anhydride-4,4 -diphenylmethanediisocyanate copolymer membrane gave 30 1/m2 day and 98.2%, respectively. 

Wood Composites—these are resin-bonded composite boards where the particles are wood shavings, flakes, chips, or fibers bonded with thermosetting adhesives that can be urea formaldehyde, melamine formaldehyde, phenol formaldehyde, or diisocyanate. In recent years, the markets for OSB and MDF board have been rapidly increasing. Most particle board production uses urea-formaldehyde as a binder that is acid setting. Hence, sodium borates (alkaline) can interfere with the setting. As a result, boric acid has been the major boron compound used as the flame retardant in particle board.28 29 Typically, a loading of 12%-15% of boric acid in MDF is required to meet the ASTM E-84 Class A rating. If sodium borate is used as a flame retardant, phenol-formaldehyde binder, that is compatible with alkaline chemicals, is commonly used. 

Some of the most familiar reactions falling into the polycondensation class are those leading to polyamides derived from dicarboxylic acids and diamines, polyesters from glycols and dicarboxylic acids, polyurethanes from polyols and polyisocyanates, and polyureas from diamines and diisocyanates. Similar polymer formations utilizing bifunctional acid chlorides with polyols or polyamines also fall into this class. The condensations of aldehydes or ketones with a variety of active hydrogen compounds such as phenols and diamines are in this group. Some of the less familar polycondensation reactions include the formation of polyethers from bifunctional halogen compounds and the sodium salts of bis-phenols, and the addition of bis-thiols to diolefins under certain conditions. 

Nylon block copolymers were previously synthesized from the anionic polymerization of caprolactam in the presence of polyurethane prepolymers. (11) The prepolymers, prepared from the reaction of diisocyanates with polyether glycols, contained Isocyanate end groups which initiated caprolactam polymerization. Sodium caprolactam was used to catalyze the reaction. This copolymer system is the basis for some current areas of nylon 6 RIM research. (12) NYRIM nylon block copolymers are formed from stoichiometric mixtures of polymeric polyols and caprolactam using poly acyllactam initiation which was described previously. The reactions are as follows ... 

In this study a diisocyanate or the product of the reaction between a diisocyanate and the impact modifier was used as accelerator. The polymerization was catalysed with common basic catalysts such as potassium lactamate, sodium lactamate and/or bromomagnesium lac tamate. 

Toluene-2,4-diisocyanate 62-76-0 Sodium Oxalate 67-68-5 Dimethyl Sulfoxide... 

Treatment of trichloroisocyanuric acid (or sodium dichloroisocyanurate) with phosgene at 150-250 "C in 1,3,5-trichlorobenzene or 1,2-dichlorobenzene affords carbonyl diisocyanate, CO(NCO)j, in almost quantitative yield [616] ... 

Then yields of isocyanates prepared by such routes can be good. Romano made 1,6 diisocyanatohexane from hex-amethylenediamine in an overall yield of 77% using a sodium methoxide catalyst to form the intermediate bisurethane.21 (Enichem is putting up a pilot plant to study the commercialization of such processes.22) Ookawa et al. ran a similar conversion to produce the diisocyanate in 92.5% yield with 1.2% monoisocyanate, which could be recycled to the process (2.6).23... 

Materials and Purification. The diisocyanates employed for kinetic studies were distilled prior to use. Reagent grade n-butanol was treated with sodium... 

A wide range of chemical agents, catalysts and conditions for the glycolysis of unsaturated polyester resins, used in the manufacture of buttons, have been described in a recent patent.34 In addition to different metal acetates, the following compounds have been proposed to be catalytically active in PET glycolysis sodium methylate, sodium ethylate, sodium hydroxide, methane-sulfonic acid, magnesium oxide, barium oxide and calcium oxide. Different applications of the depolymerization products were described, e.g., preparation of fresh unsaturated polyesters by reaction with maleic acid, maleic acid/ phthalic anhydride or maleic anhydride/terephthalic acid or the synthesis of polyurethane resins by reaction with a diisocyanate. 

The use of blocked isocyanates for aqueous systems is of special interest. The sodium bisulfite blocking of hexamethy1ene diisocyanate was already described in Petersen s classic paper on blocked isocyanates ( ). Its application in cross-linking paper (75) and acrylamide copolymers (76) has been described. The stability of bisulfite-blocked aromatic isocyanates in water can present a difficulty, and various stabilizer systems have been proposed. Peters and Reddie (77) have made an extensive study of the various factors affecting stability and have found that optimum stability was obtained at pH of 2-3 in aqueous ethanol with excess hydrogen peroxide. 

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