Methanol, basic, separation

The methanol carbonylation is performed ia the presence of a basic catalyst such as sodium methoxide and the product isolated by distillation. In one continuous commercial process (6) the methyl formate and dimethylamine react at 350 kPa (3.46 atm) and from 110 to 120°C to effect a conversion of about 90%. The reaction mixture is then fed to a reactor—stripper operating at about 275 kPa (2.7 atm), where the reaction is completed and DMF and methanol are separated from the lighter by-products. The cmde material is then purified ia a separate distillation column operating at atmospheric pressure. 

Chemical Structure of Analytes and Composition of the Eluent Employed for Testing the Capability of Acetonitrile and Methanol in Separating Basic Compounds... 

As shown in Figure 4.11, the methanol spectroscopic scale is very weakly correlated to the methanol basicity ( = 42, r = 0.737). Only 54% of the variance of AG is explained by Av. Some resolution of the scatter diagram is, however, achieved by noting good correlations of AG with Av(OH) when separating the families ofpyridines, ethers and polar bases (nitrile, sulfoxide, sulfone, carbonyls and phosphoryls) which obey Equations 4.29,4.30 and 4.31,... 

This is my version, but may be better done. First one, evaporate methanol, better with vacuum. Then we have two layers similar in volume, we add 100 of solvent and 50 cc of basic solution (sodium carbonate, bicarbonate or 10 % NaOH ). We shake it and may be we will have little more precipitate or tar. Also may be we can t see separation, then w/e add a bit more solvent without shaking to see separation. We make two more extractions with 50 cc of solvent. Even if we can t see separation, we can add enough HCI and shake, this will forme some tar and layers will be distincts, so we can separate and make a basic wash. Sometimes I ve done first an acid wash, but I can t sure it s better. I m thinking now may be is better to do all extraction as Strike s top 3. Add acid solution, like 250 cc (less PdClz and no CuCI) 15% HCI, extract and make a basic wash. 

Methyl formate and propylene oxide have close boiling poiats, making separation by distillation difficult. Methyl formate is removed from propylene oxide by hydrolysis with an aqueous base and glycerol, followed by phase separation and distillation (152,153). Methyl formate may be hydrolyzed to methanol and formic acid by contacting the propylene oxide stream with a basic ion-exchange resia. Methanol and formic acid are removed by extractive distillation (154). 

A total of 3 g (0.13 moles) of sodium hydride is added to a solution consisting of 10 g of 17 -hydroxy-5a-androstan-3-one (36 mmoles) in 200 ml of benzene and 10 ml of ethyl formate. The reaction mixture is allowed to stand under nitrogen for 3 days followed by dropwise addition of 10 ml of methanol to decompose the excess of sodium hydride. The solution is then diluted with 300 ml water and the layers are separated. The basic aqueous solution is extracted with ether to remove neutral material. The aqueous layer is acidified with 80 ml of 3 A hydrochloric acid and the hydroxymethylene steroid is extracted with benzene and ether. The combined organic extracts are washed with water and saturated sodium chloride solution and then dried over magnesium sulfate and concentrated. The residue, a reddish-yellow oil, crystallized from 10 ml of ether to yield 9.12 g (83%) of 17 -hydroxy-2-hydroxymethylene-5a-androstan-3-one mp 162-162.5°. Recrystallization from chloroform-ether gives an analytical sample mp 165-165.5° [a]o 53° (ethanol) 2 ° 252 mjj. (g 11,500), 307 m u (e 5,800). 

The use of renewable resources for manufacturing specific performance and speciality chemicals, and for fibres to replace synthetic ones, is growing. The driver for this is improved cost/performance. In order to have a major impact on the amount of oil and gas used there is a need to convert biomass into new, large-scale basic feedstocks such as synthesis gas or methanol. Many technical developments in separation science as well as improvements in the overall yield of chemicals are required before renewable feedstocks can compete effectively with oil and gas, but the gap will continue to narrow. 

Acetochlor and its metabolites are extracted from plant and animal materials with aqueous acetonitrile. After filtration and evaporation of the solvent, the extracted residue is hydrolyzed with base, and the hydrolysis products, EMA and HEMA (Figure 1), are steam distilled into dilute acid. The distillate is adjusted to a basic pH, and EMA and HEMA are extracted with dichloromethane. EMA and HEMA are partitioned into aqueous-methanolic HCl solution. Following separation from dichloromethane, additional methanol is added, and HEMA is converted to methylated HEMA (MEMA) over 12 h. The pH of the sample solution is adjusted to the range of the HPLC mobile phase, and EMA and MEMA are separated by reversed phase HPLC and quantitated using electrochemical detection. 

A polyethylene-coated (PEE) silica column was used with water-methanol eluents to achieve the separation and retention of 27 pesticides.40 The retention times of 33 commercial pesticides were determined on an octadecyl (ODS)-derivatized alumina column using water-methanol eluents and compared with retention properties on an ODS-silica column packing.41 More recently, RP-HPLC was used in combination with diode array detection for the identification and quantification of 77 pesticides (acidic, basic, and neutral) in groundwater samples.42... 

The adsorption of textile dyes on natural sorbents was investigated by various HPLC methods. The chemical structures and calculated molecular areas of the dyes are depicted in Fig. 3.83. Because of their different chemical structures and retention characteristics, the dyes were separated in different columns with different mobile phases. Basic blue 41 (BB41) was determined in an octylsilica column (75 X 4.6 mm i.d.). The mobile phase consisted of methanol-KH2P04-Na2HP04 buffer (pH = 5) in volume ratio 1 1. Acid blue... 

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