Xylene solutions

Tetracyanoethylene is colorless but forms intensely colored complexes with olefins or aromatic hydrocarbons, eg, benzene solutions are yellow, xylene solutions are orange, and mesitylene solutions are red. The colors arise from complexes of a Lewis acid—base type, with partial transfer of a TT-electron from the aromatic hydrocarbon to TCNE (8). TCNE is conveniendy prepared in the laboratory from malononitrile [109-77-3] (1) by debromination of dibromoma1 ononitrile [1855-23-0] (2) with copper powder (9). The debromination can also be done by pyrolysis at ca 500°C (10). 

Monomer conversion (79) is followed by measuring the specific gravity of the emulsion. The polymerization is stopped at 91% conversion (sp gr 1.069) by adding a xylene solution of tetraethylthiuram disulfide. The emulsion is cooled to 20°C and aged at this temperature for about 8 hours to peptize the polymer. During this process, the disulfide reacts with and cleaves polysulfide chain segments. Thiuram disulfide also serves to retard formation of gel polymer in the finished dry product. After aging, the alkaline latex is acidified to pH 5.5—5.8 with 10% acetic acid. This effectively stops the peptization reaction and neutralizes the rosin soap (80). 

Chemical Designations-iSiy/ioio>/7u l,2,3,4,10,10-Hexachloro-6,7-epoxy-l,4,4a,5,6,7,8,8a-octahydro-endo,endo-l,4,3,8-dimethanonaphthalene Hexadrin Mendrin Chemical Formula-. Not applicable. Observable Characteristics - Physical State (as shipped) Solid (Sometimes shipped as an emulsifiable coneentrate in xylene solution) Color Colorless to tan Odor. None. 

Pyrimidines have also served as electrophiles in crown synthesis from this group. 4,6-Dichloropyrimidine reacts with diethylene glycol and sodium hydride in anhydrous xylene solution to form the 20-crown-6 derivative as well as the other products shown in Eq. (3.48). Note that a closely related displacement on sy/rr-trichlorotriazine has been reported by Montanari in the formation of polypode molecules (see Eq. 7.5). 

CeH3(OCH3)a. CHOH. CHa. NH. CO. CHg. CeH3(OCH3)2, which when boiled with phosphoric oxide in xylene solution lost 2 mols. of water and formed papaverine (IV). ... 

The synthesis of meconin has been referred to already (p. 201). Cotarnine has been synthesised by Salway from myristicin (I) as a starting-point. This was transformed into jS-3-methoxy-4 5-methylenedioxy-phenylpropionic acid (II), the amide of which was converted by Hofmann s reaction into )S-3-methoxy-4 5-methylenedioxyphenylethylamine, and the phenylacetyl derivative (HI) of this condensed, by heating it in xylene solution with phosphoric oxide, giving rise to the two possible dihydroiso-quinoline derivatives. The first of these substances, 8-methoxy-6 7-methylenedipxy-1-benzyl-3 4-dihydroiioquinoline (IV), on conversion into the methochloride and reduction with tin and hydrochloric acid, gave... 

Tetrahydroharman, m.p. 179-80°, has been prepared by a number of workers by a modification of this reaction, viz., by the interaction of tryptamine (3-)5-aminoethylindole) with acetaldehyde or paraldehyde and Hahn et al. have obtained a series of derivatives of tetrahydronorharman by the use of other aldehydes and a-ketonic acids under biological conditions of pH and temperature, while Asahina and Osada, by the action of aromatic acid chlorides on the same amine, have prepared a series of amides from which the corresponding substituted dihydronorharmans have been made by effecting ring closure with phosphorus pentoxide in xylene solution. 

The first compound containing a telluroazepine ring, ll-(4-methylphenyl) dibenzo[d,/][l,4]telluroazepine 62 was obtained in 21% yield upon heating p-xylene solution of 9-azido-9-(4-methylphenyl)telluroxanthene at 130-140°C (87KGS279). Other products of this pyrolitic process are the imine 63 (32% yield) and phenanthridine 64 (21% yield). Formation of the latter implies extrusion of the tellurium atom from dibenzotelluroazepine 62. 

A mixture of 22 grams of Oi-(p-chlorophenoxy)isobutyric acid, 3.8 grams of 1,3-propane-dioi, 0.5 gram of p-toiuenesulfonic acid and 150 ml of xylene was refluxed. When the theoretically calculated amount of water had been removed, the xylene solution was washed with dilute aqueous sodium bicarbonate and then the xylene was distilled off. The residue was distilled under reduced pressure to give 11 grams (47% yield) of 1,3-propanediol bis[a-(p-chlorophenoxy)isobutyrate] boiling at 197° to 200°C/0.03 mm Hg. 

Method A To a mixture of the 9-(hydroxymethyl)-9,10-dihydroacridine (4mmol) and sea sand (10g) under N2 in refluxing anhyd xylene (30 mL) was added in four portions during a 2-h period, P205 (4g, 28 mmol). The yellow-orange mixture was heated under reflux for an additional 1.5 h, then cooled, and quenched cautiously with a large excess of cold H20. The mixture was filtered to remove the sand, and the aqueous layer was then separated from the filtrate. The sand and the aqueous layer were extracted with hot benzene and the benzene and xylene solutions were combined, dried, and the solvent removed under reduced pressure. The crude product was obtained as a yellow-orange residue which was purified by crystallization (benzene). 

Bu3P-Pt(0) complex was prepared by the literature procedure 2 FBu3P (32 mg, 0.158 mmol) (Strem Chemicals) was dissolved in platinum(0)-l,3-divinyl-l,l,3,3-tetramethyldisiloxane complex (1.5 mL of xylene solution obtained from Aldrich Chemical Company, Inc., catalog number 47-951-9). The mixture was stirred at 65°C (oil bath) for 5 min and then was slowly cooled to room temperature. This solution could be stored under N2 in the freezer indefinitely. 

Another means of observation of such radical dissociation of hydrocarbons, to a lesser extent, is achieved in modern esr spectroscopic studies. Dissociation of bitropyl [49] into the tropyl radical [3 ] was observed in m-xylene solution (11). The radical is a long-lived species but only at low concentration, 10 -10 m (Vincow et al., 1969). The radical dissociation (12) of 7-(triphenylmethyl)-l,3,5-cycloheptatriene [50] has been found to be more facile than that of bitropyl (Okamoto et al., 1970). 

The polymer formed in the reaction of EPR with 0.5 wt-% DCP at 180 C, in the presence or absence of 5 wt-% MAH, was completely soluble in refluxing xylene, although it contained a fraction insoluble in cyclohexane at 22 C. The EPR and EPR-g-MAH were fractionated by addition of the xylene solution to acetone. 

Fraction I recovered by precipitating xylene solution in acetone e Fraction II recovered by removal of solvent from filtrate Toluene, 30° ... 

In a 500-ml. distilling flask arc placed 107 g. (0.40 mole) of 7-bromopropylphthalimide (Note 1) and 240 ml. of xylene. Solution is effected by heating, and 24 ml. of xylene is distilled to remove traces of moisture. After cooling, the solution is transferred to a 1-1. round-bottomed flask with a ground-glass joint and treated with 107 g. (140 ml., 0.83 mole) of di- -buty]amine. 

Another alternate synthetic method for the manufacturing of niclosamide is reported [1], Phosphorus trichloride (PC13) is slowly introduced into a boiling xylene solution containing 5-chlorosalicylic acid and 2-chloro-4-nitroaniline in equimolar ratio and the heating continued for 3 h. Crystals of niclosamide separate on cooling and are recrystallized from ethanol [7,8], van Tonder et al. [9] prepared and characterized three crystal forms of niclosamide namely the anhydrate and the two monohydrates. 

React at 37°C (for the ethanol solution) or 55°C (for the o-xylene solution) for at least 5-6 hours with mixing. 

Tab. 5.6 Reaction of isosorbide with several alkylating agents in the presence of KOH and TBAB (relative amounts 1 3 3 0.1) under the action of microwave irradiation in a xylene solution.

The N-adducts derived by reaction of 1,5-diaminoimidazoles (96 R = NHPh, R2 = aryl, /Pr) with the /V-acylimidates (140) and (141) were cyclized smoothly in hot xylene solution to give the corresponding purines (168) and (169) in good yield (85MI1). 

In a method for the determination of copper, nickel, and vanadium in seawater, Shijo et al. [840] formed complexes with 2-(5-bromo-2 pyridylazo)-5-(N-propyl-N-sulfopropylamino) phenol and extracted these from the seawater with a xylene solution of capriquat. Following back-extraction into aqueous sodium perchlorate, the three metals were separated on a C is column by HPLC using a spectrophotometric detector. 

Solid state oxidation, both of the a- and the 3-phase [8] of dihydroquinacridone, affords crude a-quinacridone. Subsequent milling with salt in the presence of dimethylformamide produces the 7-modification, while the 3-form evolves in the presence of xylene. Solution oxidation of dihydroquinacridone, possibly performed as air oxidation in the presence of 2-chloroanthraquinone [9], forms crude 3-quinacridone. Milling with xylene likewise affords 3-quinacridone pigment (see tables of chemical structures on p. 613). 

Fluoroacetamide has also been prepared by heating a mixture of potassium fluoride and chloroacetamide at 135° under reduced pressure when fluoroacetamide and unchanged chloroacetamide distil over.3 The reaction can also be carried out in xylene solution at ordinary pressure,4 but the yield is only 55 per cent. However, the method has been improved lately, although the product still contains unchanged chloroacetamide. ... 

There have been reports in which acetylation has a detrimental affect upon mechanical properties. Reachon of Scots pine in an acetic anhydride/xylene solution for 4 hours at 145 °C resulted in a 50 % decrease in the tensile modulus (Ramsden etal., 1997). Spruce modified in acetic anhydride at 100 °C was found to exhibit a reduction in toughness of about 20 %, compared to unmodified wood (Reiterer and Sinn, 2002). 

Subsequent kinetic studies designed to elucidate the experimental rate law were conducted on o-xylene solution. Individual runs in general displayed outstanding linearity (Figure 2). The short induction... 

Poly(hydrosilane)s are stable compounds and can be manipulated in the air only for a short period since they are oxygen sensitive. In order to study the oxidation products, a xylene solution of poly(phenylhydrosilane)(Mw = 2340, Mw/Mn = 1.72) was refluxed (140 °C) for 12 h in a system exposed to the air [15]. Only minor changes were observed by GPC analysis whereas FTIR showed characteristic absorptions due to siloxane-type structures on the polymer backbone. A detailed NMR analysis, based on H NMR, Si INEPT and H- Si HMQC spectroscopies, indicated that the oxidized material contains the units 7-10 shown in Scheme 8.2. In particular, units 7,8 and 9+10 were present in relative percentages of 27%, 54% and 19%, respectively, which mean that more than 70% of the catenated silicons were altered. It has also been reported that silyl hydroperoxides and peroxides are not found as products in the autoxidation of poly(phenylhy-drosilane) [16]. 

All polymerisations were carried out in nitrogen purged xylene solutions in a thermostatically controlled one litre glass reactor. Semi-batch processes were carried out in a similar reactor which was provided with calibrated peristaltic pumps (computer controlled when necessary) for delivering the monomer feeds. Typically, experiments were carried out at 80°C with monomer concentrations which gave solids contents in the range 10 - 60% at 100% conversion. 

Fig. 50. X-Ray molecular structure of MYKO 63 from m-xylene solutions...

Chloranil is also widely applicable for the dehydrogenation of 1,2,3,4-tetrahydrocarbazoles it is generally employed in xylene solution. Substituents that have survived this procedure include the following groups trifluoralkyl, " ... 

The polymer contained in the xylene solution was further purified by repeated precipitations and washings of the polymer precipitated with anhydrous xylene at —70°. 

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