Dessicated

Transfer the filtrate to a ceramic evaporating dish and heat on a water bath until a crystalline scum forms on the top. Cool the dish quickly then filter the mess on the vacuum Buchner to yield 96g of Methylamine Hydrochloride. Concentrate the filtrate once again to obtain a second crop of crystals, -IQg. Concentrate the filtrate a third time as far as possible using the water bath, then store the dish in a vacuum dessicator loaded with Sodium Hydroxide in the bottom for 24 hours. Add Chloroform to the residue left in the crucible to dissolve out Dimethylamine Hydrochloride (distill off the Chloroform to recover - good stuff) then filter on the venerable old vacuum Buchner funnel to yield an additional 20g of Methylamine Hydrochloride, washing the crystals in the funnel with a small poiiion of Chloroform ( 10mL). 

Purification of the Methylamine HCI is in order now, so transfer all of the crude product to a 500mL flask and add either 250mL of absolute Ethanol (see end of FAQ for preparing this) or, ideally, n-Butyl Alcohol (see Footnote 4). Heat at reflux with a Calcium Chloride guard tube for 30 minutes. Allow the undissolved solids to settle (Ammonium Chloride) then decant the clear solution and cool quickly to precipitate out Methylamine HCI. Filter rapidly on the vacuum Buchner funnel and transfer crystals to a dessicator (see Footnote 3). Repeat the reflux-settle-cool-filter process four... 

Fig. 6. Adsorption capacity of various dessicants vs years of service in dehydrating high pressure natural gas (39). a, Alumin a H-151, gas 27° C and 123 kPa, from oil and water separators b, siUca gel, gas 38° C and 145 kPa, from oil absorption plant c, sorbead, 136-kPa gas from absorption plant ...

A convenient laboratory method for the preparation of BCl is by the reaction of AlCl and BF or BF (47—49). More recently a patent describing the preparation of BCl by halogenating B(OH)2 or esters of B(OH)2 using an excess of the oxychloride of S or P in the presence of a dessicant and catalytic amounts of Fe, Co, or Ni, at temperatures below 100°C was issued (50). This process eliminates formation of carbonic dichloride [75-44-5] ... 

Nitrosobenzene [586-96-9] M 107.1, m 67.5-68 , b 57-59 /18mm. Steam distd, then cryst from a small volume of EtOH with cooling below 0°, dried over CaCl2 in a dessicator at atm pressure, and stored under N2 at 0°. Alternatively it can be distd onto a cold finger cooled with brine at —10 in a vac at 17mm (water pump), while heating in a water bath at 65-70° [Robertson and Vaughan J Chem Educ 27 605 1950]. 

Dessicate all filters at least 24 hours before weighing and sampling. Change deSsicant before it completely changes color (e.g., before blue dessicant turns all pink). Evacuate dessicator with a sampling or vacuum pump. 

Anhydrous An anhydrous material does not contain any water molecules. Many substances occur naturally as hydrates, compounds that have a specific number of water molecules attached to them. This water can often be removed by heating and/or vacuum to give the anhydrous material. Anhydrous materials can absorb water from their surroundings and find use as dessicants. Examples include those packets of silica gel you find in some consumer goods, as well as dehumidifying sachets used in clothes closets. When an anhydrous material reacts with water, this could release a large amount of heat, possibly leading to a heat or pressure buildup that could result in an explosion. 

Ferrous Picrate. [C6H2(N02)30] 2Fe, mw 513.15, N 16.38%, dark green powder which expld feebly at 315—20°. It was obtained by drying the octahydrate in a vac dessicator over sulfuric acid. Its impact sensitivity was 14-15" (vs 14" for TNT). The octahydrate was obtained by treating a hot coned aq soln of ferrous sulfate with Ba picrate yel hexagonal prisms which turned brown on standing impact sensitivity 36"... 

A very violent detonation occurred when silver permanganate was dried under vacuum in a dessicator containing sulphuric acid, it was thought that this accident was due to the formation of dimanganese heptoxide, which is extremely explosive through the action of sulphuric acid vapour on silver permanganate. 

An accident of the same nature happened when it was dried with diphosphorus pentoxide. In this case, it is unlikely that the reason for it is the formation of an acetylene salt. The author believes that, since water plays a desensitising role on this compound, it leads to a very unstable pure alcohol when it is removed by strong dehydrating agents. The temperature rise due to the dessicating agent hydration is sufficient to decompose the pure alcohol violently.This interpretation could also be applied to the previous case. 

Feces Dessication and pulverization of sample digestion with hot acid in Paar bomb ICP/AES 10-50 pg/L >86 Que Hee and Boyle 1988... 

Hydrated or slaked lime Ca(OH)2 is an inorganic accelerator used in the curing of fluoroelastomers. In conventional sulphur cured polymers it counteracts the retardation of cure due to the presence of acidic substances in a rubber compound. Quicklime (CaO) dispersed in mineral oil or in wax/oil is used as a dessicant to reduce porosity in vulcanisates, particularly in fluid bed curing. 

Foals fed 29 or 250 mg Zn/kg diets had normal serum copper and zinc concentrations. Those fed 1000 or 2000 mg Zn/kg diet became hypocupremic in 5 to 6 weeks and developed lameness owing to cartilaginous disease similar to osteochondritis dessicous. Foals fed high zinc diets became lame when serum copper fell to 0.3 mg/L for >1 week at end of study arthritic foals had <0.2 mg copper/L serum. Serum zinc concentrations rose to >2 mg/L within 2 weeks at 1000 or 2000 mg Zn/kg diet liver zinc was <333 mg/kg DW at diets of <250 mg Zn/kg, 2728-3511 mg/kg DW at 1000 mg Zn/kg diet, and 4364-4524 mg/kg DW at the highest dietary loading of 2000 mg Zn/kg in 15 weeks Decreased growth, lameness, bone deformities, death. 

To a solution of triphenyl phosphite (6.2 g, 0.02 mol) and thiomethoxy-acetaldehyde (2.25 g, 0.025 mol) in glacial acetic acid (18 ml), powdered N-phenylthiourea was added in a single portion. The reaction mixture was stirred at room temperature for 30 min and then for 30 min at 80°C. After the mixture was cooled to room temperature, water (5 ml) was added and the solution was maintained at room temperature for 10 h. The precipitate was removed by suction filtration, washed with 1 1 acetic acidtwater (2 x 10 ml), dried over potassium hydroxide in an evacuated dessicator, and recrystallized from chloroform/ methanol. In this manner there was isolated pure 0,0-diphe-nyl 2-methylthio-l-(iV-phenylthioureido)ethylphosphonate (8.61 g, 94%) of mp 136 to 138°C, which exhibited spectra and analytical data in accord with the proposed structure. 

Place stub in a dessicator over night to remove excess moisture. 

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