Methanol immersion

Askari et al. [15] have compared purge and trap, methanol immersion and hot solvent extraction methods for the determination of volatile organic compound in aged soil. These workers found that hot solvent extraction is much more effective than the US Environmental Protection Agency approved purge and trap technique [7, 8]. 

Polysulfide Methanol Immerse overnight in strong chlorine water, wash, and dry. ... 

Infiltration of the permeable concrete with molten sulfur yields a matrix which is almost impermeable to water. The freeze-thaw durability tests have indicated this is so, and immersion tests showed that fully infiltrated specimens absorbed less than 0.3% water by volume over several months, although methanol immersion and vacuum poro-simeter measurements revealed that a pososity of over 5% was available for filling. A total shrinkage of about 13% (Table I) occurs when liquid sulfur crystallizes to the stable low-temperature S< form, but much of the volume change appears to be accommodated in closed pores and intercrystal inversion fractures which affect the permeability little. 

Soil type (component) Compounds Purge and trap " , mg/kg Methanol immersion " , mg/kg Hot methanol extraction " , mg/kg... 

Fe and steels Nital 1-10 ml HN03 in 90-99 ml methanol Immerse few seconds to 1 minute... 

Figure 9.20 shows the out-of-plane birefringence of a CTA film containing 5 wt% of TCP with the data of pure CTA before and after methanol immersion. As seen in the figure, addition of TCP greatly enhances the out-of-plane birefringence of CTA. Since the evaporation rate is not affected by the addition of TCP, the enhancement is attained by the orientation of TCP molecules in the film plane accompanied with CTA chains. 

Figure 9.20 Wavelength dispersion of out-of-plane birefringence for CTA ( ) and CTA/TCP before ( ] and after ( ) methanol immersion. The cast films with a thickness of 100 pm were prepared by CH2CI2/CH3OH at a standard condition.

In order to further confirm the contribution of TCP, the stretched sample of CTA/TCP (95/5] blend was immersed in methanol for 24 hours to remove TCP, and the orientation birefringence was measured. No considerable change in the dimension of the sample after 24 hours of immersion is observed, suggesting there is almost no alteration in the degree of stretching upon the methanol immersion. Furthermore, it is affirmed by IR spectra analysis that TCP has been completely removed. 

Fig. 4.24 Heat of immersion of a carbon (prepared by pyrolysis of Saran Polymer A) in different liquids at 300 K. The liquids for points 1-6 were (I) methanol (2) benzene (3) n-hexane (4) 3-methyl benzene (5) 2,2-dimethyl butane (6) 2,2,4-trimethyl pentane. The abscissae represent the molar volumes of the liquids. (Redrawn from the original diagram of Barton, Beswick and Harrison. " )...

B. cis-1,2-Gyclohexanedimethanol Dimethanesulfonate. In a 5-1., three-necked, round-bottomed flask, immersed in an ice-salt bath and fitted with a mechanical stirrer and an addition funnel, is plaeed a solution of 111 g. (0.97 mole) of methanesulfonyl chloride in 1.21. of pyridine. While cooling and stirring, a solution of 46.4 g. (0.322 mole) of m-l,2-cyclohexanedimethanol in 250 ml. of pyridine is added dropwise at a rate such that the temperature does not exceed 0° (Note 5). Upon completion of the addition, the mixture is stirred at — 5° to 0° for an additional 2 hours. Two liters of cold 10% hydrochloric acid is introduced at a rate which maintains the reaction mixture below 20° (Note 5). The solid which separates is isolated by suction filtration, washed sequentially with 11. of dilute hydrochloric acid and 21. of water, and air-dried. There is isolated 93-95 g. (96-98%) of the dimethanesulfonate having m.p. 66-67.5°. Reorystallization from methanol gives needles melting at 75-76° (Note 6). 

Immersion well (quartz or pyrex), fitted with inlet (a) and outlet (6) for cooling liquid e.g. methanol), and with ground joint (c) to Reaction flask, fitted with outlet d) to vacuum system ( 10 mmHg) Liquid nitrogen Dewar flask... 

Note in making up the chromic acid solution it is advisable to dissolve the silver nitrate separately and add it to the boiling chromic acid to prevent excessive crystallisation of the silver chromate. The chromic acid must be free from sulphate to avoid attack on the zinc. Immerse each specimen for 15 s in a 6% solution of hydriodic acid at room temperature to remove the remaining corrosion products. Immediately after immersion in the acid bath, wash the samples first in tap water and then in absolute methanol, and dry in air. This procedure removes a little of the zinc and a correction may be necessary. 

A. Ethyl 4-Amino-3-(methylthiomethyl)benzoate [Benzoic acid, 4-amino-3-[(methylthio)methyl]-]. A 1-1., three-necked, round-bottomed flask is fitted with a mechanical stirrer, a condenser topped with a gas-inlet tube, and a two-neckcd adapter holding a low-temperature thermometer and a 100-ml., pressure-equalizing dropping funnel. The flask is charged with 10.50 g. (0.10 mole) of ethyl p-aminobenzoate [Benzocaine Benzoic acid, 4-amino-, ethyl ester] (Note 1), 300 ml. of acetonitrile, and 100 ml. of dichloromethane, is flushed with nitrogen, and is then immersed in a 40% aqueous methanol-dry ice bath maintained between... 

Note The individual components of the reagent can also be applied separately one after the other [12, IS], e.g. the chromatogram is first immersed in an 8% methanolic 4-(dimethylamino)-benzaldehyde solution and then, after intermediate drying, sprayed v th 25% sulfuric acid [12]. 4-(Dimethylamino)-benzaldehyde can be replaced in the reagent with 4-(dimethylamino)-ciimamaldehyde [1]. 

Self-assembled monolayers are formed spontaneously by the immersion of an appropriate substrate into a solution of active surfactant in an organic solvent. After the substrate is immersed for a time from minutes to hours, it is rinsed with ligroin, methanol, distilled water, and dried in a steam of nitrogen. An apparent effect of the monolayer coating is the drastic change in wettability of the surface so that the measurement of the contact angle can be considered as an effective way to detect the formation of the SAMs. 

Recently, cryo-ground mbber tire (GRT) has been successfully treated by immersion for 20 min at room temperature in TCI solution in methanol of different concentrations (1-5 wt%). The wettabUity and the extent of chlorination of GRT increases with increased concentrations of TCI, and a small extent of surface oxidation occurs. Optimum performance was obtained for 3 wt% TCI-methanol solutions. 

---