Micro condenser

During carbonisation phase the basic material is gas out, e.g. devolatized. This process opens the pores where the distribution of the micro pores, meso pores and the macro pores arc approximately reflections of the pore characteristics of the original basic material. This is most important that the carbonisation phase perfectly devolatize the basic material, through to core structure, as in erfect devolatizadon may result internal micro condensation of the tar, which may significantly decrease the expanded pore developments. 

Formation of Methyl- -Naphthyl Ether. In a test tube provided with reflux micro-condenser place 0.5 g of /3-naphthol, 2 ml of 10 per cent sodium hydroxide solution, and 0.5 ml of methyl iodide. Warm for 20 minutes in a water bath, and then note the odor. Add 5 ml of water and filter the crystals, washing with water. The ether may be recrystallized from alcohol. 

B) Preparation of Aniline (Sm.). (Use of tin as a reducing agent.) Place 3 ml of nitrobenzene and 14 ml of concentrated hydrochloric acid in an eight-inch tube, and arrange for reflux with a micro condenser. Add in small portions 6.5 g of granulated tin. The reaction is controlled by the rate of addition of the metal. Shake the tube from time to time. When all the tin is added, boil gently for half an hour until the odor of nitrobenzene disappears. 

A) Preparation of Ethyl Acetate (Sm.). Place in an eight-inch tube 5 ml of ethanol, 5 ml of glacial acetic acid, and 0.5 ml (7-8 drops) of sulfuric acid. Insert a micro condenser in the tube arranged for reflux, and heat for 0.5 hours. Remove the reflux condenser and distill from a water bath until no more distillate passes over. The distillate consists of ethyl acetate and small amounts of acetic acid, ethanol, water, and sulfur dioxide. The latter was formed by the oxidizing action of the sulfuric acid. Add 2 ml of a saturated solution of sodium carbonate to the mixture in the re-... 

C) Preparation of Methyl Benzoate (Sm.). Place in an eight-inch tube provided with a micro condenser 5 ml of methanol, 5 g of benzoic acid, and 0.5 ml of concentrated sulfuric acid. Reflux for half an hour in a water bath. Dilute with 6-8 ml of water, and separate the ester. Dry with 0.5 g anhydrous potassium carbonate, and distill from a small distilling tube. The fraction which boils at 195-205° is collected. 

G) Hydrolysis of Esters. Place 2 ml of ethyl or methyl benzoate 3.nd 10 ml of 10 per cent sodium hydroxide solution in a test tube provided with a micro condenser. Heat in a water bath for 20-30 minutes until the ester layer disappears. The solution contains the alcohol and the sodium salt of the acid. If it is desired to separate the alcohol, the liquid is distilled until 5 ml of distillate is collected otherwise, the solution is cooled, and acidified with hydrochloric acid. Benzoic acid separates from the solution. The crystals are filtered and dried. 

A) Preparation of Acetamide (Sm.). Place in an eight-inch distilling tube 10 ml of glacial acetic acid, and add slowly 4 g of ammonium carbonate, a little at a time. When the evolution of carbon dioxide has subsided, attach to the mouth of the tube a micro condenser arranged for reflux. The end of the condenser should be just... 

A) Preparation of Succinic Anhydride (Sm.). Use the same apparatus as described for the preparation of acetyl chloride (Experiment 40 A). Place in the distilling tube 5 g of succinic acid and 9 ml of acetic anhydride. Adjust the micro condenser for reflux, and heat in the water bath at 90-100° for 30-45 minutes until a clear solution is obtained. Remove the distilling tube from the water bath and attach to the side arm (through a short rubber tubing) a calcium chloride tube. When the tube has acquired room temperature cool in an ice-salt mixture. Filter the crystals with suction and wash twice with 4 ml portion of ether. Place the product in a bottle. The yield is 3-4 g. 

Note The directions for the experiments are for semimicro work. For macro work, use five times the quantities given instead of an e ht-inch tube, use a 250-500 ml flask, a Liebig condenser instead of a micro condenser, a distilling flask instead of a distilling tube. Use the same directions and allow about 50 per cent more time. 

E) Preparation of Thymolphthalein. Prepare the reaction mixture, following the same procedure as in section (D). Use 6 g of th3unol, 3.7 g of phthalic anhydride, and 3-4 g of zinc chloride. Heat for 8 hours at 105-110°. Cool, and add 20 ml of a mixtme of equal parts of ether and benzene. Provide the tube with a micro condenser, and reflux in the water bath for fifteen minutes to dissolve the unreacted th3unol. Cool, and decant the solvent. Add 30 ml of methanol, heat to dissolve the phthalein, and pour the hot extract into a beaker. Repeat the extraction with 10-15 ml of alcohol. The residue consists of zinc chloride. Save it for future reference, if the yield of the phthalein is low. Add to the alcohohc extract water in small amounts until precipitation begins, and then cool. After an hour filter the crystals of thymolphthalein. If the product is colored, dissolve in the minimum amount of hot alcohol and precipitate by slow addition of water. 

Raise a water bath under the flask and heat at 60-70° for 10-12 hours. Remove cork and arrange for distillation. Use a one-hole cork on the flask and connect by means of a glass tube to a regular micro receiving setup. Distill the mixture of thionyl chloride and benzene until the amount of the distillate collected is about 8 ml. Add 80 ml of dry benzene to the residue in the flask and replace the micro condenser on the mouth of the flask so that the benzene can be refluxed for 10-15 minutes. While the benzene is refluxing place a Bunsen funnel over a 250-ml Erlenmeyer flask with a folded filter paper in the funnel. Put the apparatus in the hood. Pour the hot benzene extract into the folded filter paper. 

This boundary condition allows the analysis of micro-condensers and micro-evaporators with finite wall thermal resistance. It is evident that when Uy, tends to infinity, the T3 boundary condition reduces to the T boundary condition. 

Micro-condensers, micro-evaporators with negligible wall thermal resistance... 

Figure 11.10 Details of the SINTEF micro-condenser. Refrlgerant-sIde pressure drop was 180 kPa/m with a mass flux of 165 kg/m s (Munkejord et al., 2002).

This condition can be applied for micro-condensers and for micro-evaporators where an external two-phase flow sets as constant the wall temperature of the microchanneis inside which a single-phase fluid flows. 

Kondensortrieb micros condenser adjustment knob, substage adjustment knob Konditionieren/Konditionierung med/chromat conditioning Konfektionierung (ready-made/industrial) manufacture/manufacturing Konfidenzgrenze/... 

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