Determination methanol number

B. Method for determining the number of —COOH groups in a molecule The TMS derivative of an acid can be converted to the methyl ester using anhydrous methanolic HQ. 1 2 3 Obtain a mass spectrum of the TMS derivative of the acid, and then evaporate the TMS reaction mixture with clean, dry nitrogen. Add 250 pd of anhydrous methanolic HC1 (Pierce cat. no. 33050) and heat at 60° for 20 min. Many TMS derivatives of acids are converted to methyl esters at room temperature after 20 min. If the sample is rerun as the methyl ester, the number of carboxyl groups can be determined by the mass differences before and after making the methyl ester from the TMS derivative. 

Charge measurements, as mentioned above, were also performed using the porous Pt electrodes required by the on-line MS technique. At low methanol concentrations (10 2 M), the charge ratio QaJQm, near 1 indicates that (C,0, H) must be the predominant adsorbate composition [14,47], This result is in good agreement with that of Heitbaum and co-workers [15] who used Eq. 1.2 to determine the number of electrons, n, per C02 produced from methanol adsorbate. They found for n a value of 3, which would be in agreement with reactions 2.1 or 2.2 for methanol adsorption. 

Note that no reoptimization of HF orbitals is required, since the set of all possible CSFs is complete . However, tliat is not much help in a computational efficiency sense, since the number of CSFs in a full CI can be staggeringly large. The trouble is not the number of electrons, which is a constant, but the number of basis functions. Returning to our methanol example above, if we were to use Hie 6-31G(d) basis set, the total number of basis functions would be 38. Using Eq. (7.9) to determine the number of CSFs in our (14,38) full CI we find that we must optunize 2.4 x 10 expansion coefficients ( ), and this is really a rather small basis set for chemical purposes. 

Biddulph and Kalbassi (1988) investigated the distillation of the ternary system methanol(l)-l-propanol(2)-water(3). In separate experiments they determined the numbers of transfer units for each binary pair that makes up the ternary system. Estimate the number of transfer units for the ternary system at total reflux if the composition of the liquid leaving the tray is... 

Y Ni, GJ Kubes, ARP van Heiningen. Methanol number A fast method to determine lignin content of pulp. J Pulp Pap Sci 16(3) J83-J86, 1990. 

Similar solubility behavior of polyhydroxy compounds was shown in fused acetates by Burton and Crowell. Burton observed that solubility of several organic compounds at 200°C, in (Li, Na, K) acetate eutectic (mp 180°C) increases with the number of hydroxyl groups and with acidity. In weight percent the following approximate solubilities were determined methanol, 0.05% 2,4-dinitroaniline and 4-nitroaniline, < 0.5% hydroquinone and resorcinol, 1% 2-amino-2-hydroxymethyl-l, 3-propanediol and 2-amino-2-methyl-l,3-propanediol, I0% trimethylolethane and pentaerythritol were miscible in all proportions above their melting points. 

On the assumption that methanol behaves like one-half of a water molecule, Holz et al. [15] have proposed the use of Eq. 7 to determine the number of coordinated methanol molecules, where tCHjOH and tch,od are the experimental lifetimes (in milliseconds) of the metal emitting states in CH3OH and CH3OD and r is 2.1 and 8.4 for the Eu3+ and Tb3 + compounds, respectively. 

Determine the number of theoretical stages required and the optimum stage locations for the feed and liquid side stream for the distillation process shown below assuming that methanol (M) and ethanol (JB) form an ideal solution. Use the Antoine equation for vapor pressures. 

Consider the FS two-column configuration for the separation of methanol and water in Figure 20.2 and (a) determine the number of degrees of freedom for the overall system, (b) deter-... 

Values of pK in the water-methanol and the water-l,4-dioxane mixtures were determined a number of times [23-27]. However, in mixtures with 1,4-dioxane, the results of Schwarz et al. [23] and Papanastasiou and Ziogas [24] are inconsistent It seems that the Schwarz et al. pKj values are incorrect. Papanastasiou and Ziogas also determined dissoeiation constants in the ternary water + methanol + 1,4-dioxane system [28]. pKj values in the water-methanol mixtures, as obtained by Garrido et al. [27] are slightly shifted with regards to those in other investigations. They also determined dissociation constants of citric acid in the water + methanol + KCl system, bnt only at one eonstant ionie strength of 7=0.15 M KCl. 

SOLVE Follow the conceptual plan to solve the problem. Begin by using the mass of methanol to determine the number of moles of methanol. 

A gas stream is flowing at a rate of 100 kmol/h at 100°C and 6000 kPa pressure enters a gas absorber. The primary objective of the COj absorber is to absorb CO2 contained in the feed stream by contacting counter-currently with methanol solvent in an absorber. The gas stream contains 0.35 CO, 0.002 H20,0.274 CO2,0.37 H2,0.002 CH4, and 0.002 Nj. Methanol at 30°C and 6000 kPa is used as an absorbent solvent. The molar flow rate of methanol liquid is 330 kmol/h. Determine the number of theoretical trays required to achieve 0.06 mol fraction of CO2 in the exit stream, column diameter, and height. 

On the assumption that methanol behaves like half a water molecule, Holz et al. (1991) have proposed the use of the following equation to determine the number of coordinated methanol molecules ... 

Using estimates of proven reserves and commitments to energy and chemical uses of gas resources, the net surplus of natural gas in a number of different countries that might be available for major fuel methanol projects has been determined. These are more than adequate to support methanol as a motor fuel. 

Methanol can be converted to a dye after oxidation to formaldehyde and subsequent reaction with chromatropic acid [148-25-4]. The dye formed can be deterruined photometrically. However, gc methods are more convenient. Ammonium formate [540-69-2] is converted thermally to formic acid and ammonia. The latter is trapped by formaldehyde, which makes it possible to titrate the residual acid by conventional methods. The water content can be determined by standard Kad Eischer titration. In order to determine iron, it has to be reduced to the iron(II) form and converted to its bipyridyl complex. This compound is red and can be determined photometrically. Contamination with iron and impurities with polymeric hydrocyanic acid are mainly responsible for the color number of the merchandized formamide (<20 APHA). Hydrocyanic acid is detected by converting it to a blue dye that is analyzed and deterruined photometrically. 

The following table gives exchange rates in methanolic sodium methoxide for a number of hydrocarbons and equilibrium acidities for some. Determine whether there is a correlation between kinetic and thermodynamic acidity in this series of compounds. If so, predict the thermodynamic acidity of the hydrocarbons for which no values are listed. 

Two linear columns from Showa Denko, Shodex SB-806M and Shodex SB-806MHQ, and two linear columns from TosoHaas, TSK GM-PWxl and TSK GM-PW, were evaluated. Prior to the evaluation, the number of theoretical plates for Shodex SB-806MHQ, SB-806M, PWxl, and PW was determined to be 15,100, 15,700, 11,390, and 4710, respectively, as per manufacturer inspection. The lower plate count of the TSK PW column is due to the larger particle size of this column. Two mobile phases, water with 0.1 M LiNOi and 50 50 methanol/water (v/v) with 0.1 M LiNOi, were used for each of the four columns. These four columns were new and only PEO and PVP were analyzed with these columns in this study. Waters Ultrahydrogel columns have also been used in this laboratory. However, Ultrahydrogel columns are exactly the same as the TSK GM-PWxl columns based on the calibrations curves supplied by the manufacturers and by the pyrolysis GC data discussed later. 

Several determinations of the number of propagation centers by the quenching technique have been carried out (98, 111). As a quenching agent methanol, labeled C14 in the alkoxyl group, proved to be suitable in this case. The number of active centers determined by this technique at relatively low polymerization rates (up to 5 X 102 g C2H4/mmole Cr hr at 75° and about 16 kg/cm2) (98, 111, 168) in catalysts on silica was about... 

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