Soxhlet assembly

Alternatively the reaction calorimeter can be fitted with a reflux condenser, ora modified Soxhlet assembly can be used. Both of these approaches are described below. It is difficult to obtain accurate calorimetric data with such reflux calorimeters if ... 

Cleaning for fluorine service. It is important that materials that may contact elemental fluorine be thoroughly cleaned to remove any traces of grease or other substance that may ignite on contact with fluorine. Furthermore, it is important to passivate all surfaces that may contact fluorine. Refer to the manufacture s fluorine material safety data sheet for more information. The assembled anodes used in the laboratory were degreased by refluxing overnight with trichlorotrifluoroethane in an oversized Soxhlet extractor. 

Weigh a finely ground representative crop sample (20 g for grain or 10 g for straw) into a cellulose extraction thimble. Assemble a Soxhlet extractor using a 500-mL round-bottom flask containing 200 mL of acetone and boiling chips. Place the extraction... 

In every analysis of propellants an extraction must be performed. The latest description of the method used by the US Armed Forces is of 1971 (Ref 5). Roweg, Soxhler or equivalent extractor must be used and as extracting solvent, diethyl ether or anhydrous methylene chloride. Proceed as follows Transfer an accurately weighed sample of propint, about 5g, to the thimble of the extractor and add prescribed solvent to the tared extraction flask. Insert the open lower part of the extractor into die neck of the extraction flask and insert thru the upper opening of the extractor die bottom opening of the reflux condenser. Assemble the apparatus on the hot plate, and adjust the temperature so that the solvent drips from die condenser at the rate of 2—3 dtops per second. Extract for a time which experience or preliminary work has shown to be adequate for the type of sample. It takes 3 to 20 hours and for Roweg extractor 2—3 times faster chan for Soxhlet. 

Pure silica mesostructures were prepared using both electrostatic surfactant (cetyltrimethylammonium bromide, CTAB) assembly and neutral alkylamine (octylamine and dodecylamine) assembly. Thus, tetraethoxysilane (TEOS) was added to solutions of framework-forming surfactants and stirred for 24 hours. The exact conditions for the synthesis procedures are described in a previous publication.20 Although Soxhlet extraction over ethanol was used to remove the framework-bound surfactant molecules from the amine-assembled mesostructures, 650°C calcination was necessary to remove the CTAB from the... 

Functional mesostructures were prepared by simultaneously adding both TEOS and MPTMS to solutions of various surfactants, including alkylamines (octylamine and dodecylamine) and non-ionic surfactants (Tergitol 15-S-12 and Triton-X). The exact conditions for these synthesis procedures have been described in other publications.19,21 The mixtures were stirred for 24 hours and the products filtered, air dried and washed free of the assembly surfactant by Soxhlet extraction over ethanol for 24 hours. 

To perform a dialytic extraction, the apparatus is assembled and preextracted for 48 hours using pyridine and methylene chloride outside and inside the membrane, respectively. The coal ftvlOO g) is then slurried in a 2-3 fold excess of pyridine (ACS reagent grade) and placed in the sample compartment, where it is constantly stirred. The methylene chloride reflux is begun at this point, and the extract collects in the receiver. When the buildup of pyridine in the receiver results in stoppage of the reflux cycle, the contents of the receiver are collected, and it is refilled with clean methylene chloride. The overflow from the sample compartment was evaporated under a flow of dry nitrogen, redissolved in pyridine, and replaced in the sample compartment daily. The dialytic extraction is slower than the soxhlet procedure, and the yield is substantially less. For example, the yield of a four day dialytic extraction of Powhatan Coal was 6%, while a two day pyridine soxhlet on the same coal yields 12-15% extract. 

Fig. 5 Surface-plasmon resonance curves, i.e., reflectivity-vs-incident angle scans of the bare substrate, a Ag coated glass slide with a thin SiC>2 layer evaporated on top (A), after the self-assembly of a reactive monochlorosilane derivative (cf. Fig. 4a) (B), after the adsorption (from solution), covalent binding, and soxhlet extraction of the polymer cushion (C), and after the deposition of a model lipid monolayer (a layer of reactive ester derivatives of a fatty acid) (D)...

Assemble the apparatus as shown in Fig. 14.5, clamping at the joints at the flask and the top of the Soxhlet extractor. The best heat source to use for continuous operation over a long period is a mantle. 

The patentees place a Soxhlet extractor inside a pressure vessel, a idea that virtually explains itself. An amount of dry ice is placed in the vessel. Solid material which is to be extracted is placed in the thimble in the exU actor and the pressure vessel is assembled. Heat is applied to the bath which vaporizes the CO2. Cooling water in a condenser acts as... 

MCM-22 precursor samples were prepared with magadiite. The layered assembly was intercalated with CTABr/TPAOH, sonicated, Soxhlet extracted and calcined. The material was characterized by XRD, pore analysis, SEM, FTIR, elemental analysis and DTG. The samples obtained appear to be the result of magadiite layers intercalated at least partially, between MCM-22 layers. 

After the template with PMMA pattern was cleaned by oxygen plasma, it was immersed into mM MUAM, or HUT or MUDA in ethanol for 24 hours to form well-ordered hydrophilic self-assembled monolayers (SAMs) in the PMMA trench area. Then, the template with assembled SAMs was washed by ethanol several times to remove the multiple thiol layers on the top of the SAMs on the surface. Afterwards, the template was extracted by acetone with a Soxhlet extractor for 24 hours to completely remove the remaining PMMA resist in the second area. Finally, the template was immersed into mM ODT in ethanol for 24 hours to grow the well-ordered hydrophobic alkanethiols on the remaining gold area (i.e., the spacing area of the original PMMA pattern). 

In Figure 7.53 a flow-injection interface for fluorometric monitoring of focused microwave-assisted Soxhlet extraction is represented [195]. This assembly allows real-time online monitoring of the PAHs extracted from solid samples in each Soxhlet cycle and provides qualitative and semi-quantitative information from natural and spiked samples. The method has been applied to a certified reference material (CRM 524, BCR, industrial soil/organics) for quality assurance/validation. The proposed technique is as efficient as conventional Soxhlet to extract PAHs from soils but with a drastic reduction of both extraction time and organic solvent disposal. 

The starting material for assembly of asar[ ]arene macrocycles is tetramethoxybenzene (12.31), which can be prepared from commercial dihydrojybenzoquinone (12.33) in abundant quantities. We subjected (Scheme 12.11) a mixture of tetramethojybenzene and paraformaldehyde to Friedel-Crafts alleviation conditions at 80 °C in chlorinated solvents, with BF3 OEt2 as the Lewis acid. Influenced by the prior work on the synthesis of pillar[n]arenes - where pillar[5]arene is formed primarily under similar reaction conditions - we were expecting this reaction mixture to form asar[5]ar-ene as the major product. To our surprise, we found, however, that the reaction mixture produced only asar[6]arene and not even a trace of asar[5]arene. It is most likely that the increased steric demand imposed on the macrocyclic framework by the two additional methojyl groups not present in pillar[ ]arenes is responsible for this striking difference in reactivity between the asar[ ]arene and pillar[ ]arene families of macrocycles. Soxhlet extraction of the crude reaction mixture with acetonitrile as the solvent was then used as a scalable method of purification to access pure asar[6]arene (12.32a) in bulk quantities. 

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