Bubbler

The water used in the transducer bubbler system was changed from re-circulated water to water only used once. 

The bubbler inlet was changed giving a water flow from transducer towards the tube. 

The complete assembly for carrying out the catalytic decomposition of acids into ketones is shown in Fig. Ill, 72, 1. The main part of the apparatus consists of a device for dropping the acid at constant rate into a combustion tube containing the catalyst (manganous oxide deposited upon pumice) and heated electrically to about 350° the reaction products are condensed by a double surface condenser and coUected in a flask (which may be cooled in ice, if necessary) a glass bubbler at the end of the apparatus indicates the rate of decomposition (evolution of carbon dioxide). The furnace may be a commercial cylindrical furnace, about 70 cm. in length, but it is excellent practice, and certainly very much cheaper, to construct it from simple materials. 

C or a part of C is put in a sep. funnel wich is connected to flask containing B ( wich can be a bottle), and a tube connect this flask to the bubbler into flask containing A, wich have other tube to redirect No and nitrite gases. Flask A is in water bath to keep rxn temp between 20 - 30 C /reaction is slightly exothermic) and stired magnetically. MeONO is bubbled in A with a bubbler that provides little bubbles (not necessary a gas difusor, but a single tube is not enough, you must increase then B and C). Bubbler is all deep as it is possible. 

Bubbler. I ve done it widening the end of a glass tube, then puting in the hole with pression a piece of glass sponge (for feet) and... 

Hazards. If you add two much, quickly C in B, MeONO goes through sep. funnel. So close the key, but if there w/as too much addition or you shake immediatly then generation is higher than the possibilities of bubbler, and rubber on flask B can jump with a lot of foam and solution. For this reason it s better to have NaN02 dissolved, to prevent surprises, but it s not necessary. Be patient and shake. Don t forget redirect NO and MeONO fumes out to the window. 

For the aqueous solution Place 16mL of cool distilled water into your bubbler setup. The "expected, not theoretical, yield of Methylamine from this amount of reactants is 7 grams. I have used a plastic aquarium aerator tube as the bubbler with excellent results. Sure beats using an inverted funnel. 

For the HCI salt Do exactly as above except use 6N Hydrochloric Acid. 6N HCI may be produced by diluting 60.4mL of "Muriatic Acid" to lOOmL with distilled water. Evaporate the bubbler solution to dryness then add 15ml of water, lOmL 10% NaOH soln. and heat gently to a boil with constant motion until dense white fumes appear. This will remove the Ammonium Chloride. Remove from heat while stirring as it cools down. Pulverize the dry residue, then reflux with absolute Ethanol for several minutes. Filter the refluxed soln. on a heated Buchner or Hirsch funnel, then distill the alcohol off the filtrate until crystals just begin to form. Allow the soln. to cool naturally to room temperature, then cool further in an ice bath. Filter the solution on a chilled Buchner funnel with suction. The yield of Meth iamine Hydrochloride should be around 55% of the theoretical. 

Place 3 3oz packets of Mildewcide into a 1L flask with an electric heating mantle and cork in the neck connected to a gas bubbler immersed in at least 550mL of distilled water. Heat the paraformaldehyde (what is in the Mildewcide) to between 180-200C (a temp, regulator is absolutely necessary for this step or use a silicone oil bath). The paraformaldehyde will depolymerize making formaldehyde gas in about 91% yield. Alternatively, the gas can be bubbled through the Ammonia solution directly (only for the brave ). If the Formaldehyde solution will not be used immedi-... 

The cinnamate ester prepared as above (23.2 g. 79 mmol) was added as a solid slowly to refluxing xylene (500 ml) over a period of 3 h at a rate that prevented accumulation of unreacted azidocinnamate in the solution (monitored by gas evolution through a gas bubbler). The solution was refluxed for an additional 2 h after gas evolution ceased. The reaction mixture was cooled and the solvent removed in vacuo. The residue was recrystallized from methanol to give pure product (20.7 g, 99% yield). 

Analytical Methods. The official NIOSH recommended method for determining sulfur dioxide in air consists of drawing a known prefiltered volume of air through a bubbler containing hydrogen peroxide, thus oxidising the sulfur dioxide to sulfuric acid. Isopropyl alcohol is then added to the contents in the bubbler and the pH of the sample is adjusted with dilute perchloric acid. The resultant solution is then titrated for sulfate with 0.005 M. barium perchlorate, and Thorin is used as the indicator. 

Bubbles in a liquid originate from one of three general sources (1) They may be formed by desupersaturation of a solution of the gas or by the decomposition of a component in the liqiiid (2) They may be introduced directly into the liquid by a bubbler or sparger or by mechanical entrainment and (3) They may result from the disintegration of larger bubbles already in the liquid. 

Unless the hquid pool is purposely lengthened vertically in order to give additional separation via bubble fractionation, it is usually taken to represent one theoretical stage. A bubbler submergence or 30 cm or so is usually ample for a solute with a molecular weight that does not exceed several hundred. 

The technique used here has been described previously by the checkers. Instead, the submitters used a dry 500-mL, three-necked flask equipped with a variable speed mechanical stirrer, a IQQ-mL pressureequalizing dropping funnel topped by a gas inlet and a Claisen head containing a low temperature thermometer (-70 C to +35°C), and a bubbler. A stream of nitrogen followed from the gas inlet. 

A. E)-(2-Methyl-l,3-butadienyl)dimethylalane. An oven-dried, 1-L, twonecked, round-bottomed flask equipped with a magnetic stirring bar, a rubber septum, and an outlet connected to a mercury bubbler is charged with 7.01 g (24 mmol) of dichlorob1s(n -cyclopentadienyl)z1rconium (Note 2) and flushed with nitrogen. To this are added sequentially at 0 C 100 mL of 1,2-d1chloro-ethane (Note 3), 12.48 g (120 mtiol) of a 5016 solution of l-buten-3-yne in... 

A slight positive pressure of argon was maintained in the vessel throughout the reaction by using an argon line connected to both a bubbler containing Nujol and the inlet on the dry ice condenser. 

The submitters recommend that the nitrogen stream be passed through a bubbler and that the flow rate be adjusted to ca. one bubble per second. If the nitrogen flow is too fast, some of the butyraldehyde will be swept out of the flask. 

To "blanket with nitrogen," the checkers simply prepared the reaction mixture with the flask open, introduced a flow of nitrogen over the surface for a few minutes, and then closed the system with an exit through a mercury bubbler to maintain a positive pressure. 

B. 3-Chlorothietane 1,1-dioxide. Thietane 1,1-dioxide (14.0 g, 0.132 mol) is placed in a three-necked, 500-mL, round-bottomed flask fitted with a magnetic stirrer, reflux condenser and a chlorine bubbler, caution sinae ahtovine is poisonous, the reaation involving it should be done in a good hood.) Carbon tetrachloride (300 mL) is added to the flask (Note 4) and the suspension is irradiated by a 250-watt sunlamp positioned as close as possible to the reaction flask without touching it (Note 5) while chlorine is bubbled through the solution for 15 min at a moderate rate (Note 6). A copious white precipitate forms and irradiation and addition of chlorine must be stopped at... 

D. 3,3-Diahlarothietane 1,1-dioxide. Thietane 1,1-dioxide (5.0 g, 0.047 mol) Is placed In a 500-mL, three-necked, round-bottomed flask equipped with a reflux condenser, magnetic stirrer, and chlorine gas bubbler. Carbon tetrachloride (350 mL) Is added and the solution Is irradiated with a 250-watt sunlamp (Note 5) while chlorine Is bubbled through the stirred mixture for 1 hr (Note 9). Irradiation and chlorine addition are stopped and the reaction mixture is allowed to cool to room temperature. The product Is collected by filtration as a white solid (4.0-4.4 g, 49-53%), mp 156-158°C (Note 10). The product can be used without further purification or It can be recrystallized from chloroform. 

The apparatus consists of a l-l. three-necked flask fitted with a gas inlet tube extending about 3 cm. into the flask and connected to the flask through a bubbler, a thermometer extending to the bottom, a mechanical stirrer, and a reflux condenser connected at the upper end with an exit tube leading to the hood. The reaction is carried out in an atmosphere of illuminating gas (Note 1). 

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