Glass ampoules preparation

Sample Preparation. Liquid crystalline phases, i.e. cubic and lamellar phases, were prepared by weighing the components in stoppered test tubes or into glass ampoules (which were flame-sealed). Water soluble substances were added to the system as water solutions. The hydrophobic substances were dissolved in ethanol together with MO, and the ethanol was then removed under reduced pressure. The mixing of water and MO solutions were made at about 40 C, by adding the MO solution dropwise. The samples for the in vivo study were made under aseptic conditions. The tubes and ampoules were allowed to equilibrate for typically five days in the dark at room temperature. The phases formed were examined by visual inspection using crossed polarizers. The compositions for all the samples used in this work are given in Tables II and III. 

Dining preparation of tungsten(IV) dibromide oxide, appropriate proportions of reactants are heated in an evacuated sealed glass ampoule to 400-500°C. Initially only one end should be heated to prevent excessive pressure bursting the ampoule. See other GLASS INCIDENTS See other halogens, oxidants... 

A routine preparation by interaction of allyl chloride and sodium thiocyanate in an autoclave at 5.5 bar exploded violently at the end of the reaction. Peroxides were not present or involved and no other cause could be found, but extensive decomposition occurred when allyl isothiocyanate was heated to 250°C in glass ampoules. Exothermic polymerisation seems a likely possibility. 

The preparation was performed by Iandelli (1941) from the elements closed, in vacuo, in a hard glass ampoule. This was then heated up to about 700°C for 2 weeks. The slow reaction was observed with a gradual consumption of arsenic. 

Fig. 6. Equipment for the preparation of glass ampoules for MAS NMR investigations under batch reaction conditions.

A newer technique which shows promise but has not yet been fully tested is based upon the preparation and separation of aldonitrile acetates of reducing sugars (Equation 9.12). The dried sugar is dissolved in pyridine and treated with hydroxylamine hydrochloride in a sealed glass ampoule at 90°C for 0.5 hr. The mixture is cooled, acetic anhydride added, and another 30-min reaction is carried out in the resealed ampoule. Actual formation of the nitrile may occur in the injector of the gas chromatograph. Nonreducing sugars apparently do not form the nitrile but are present as the... 

To calibrate the cobalt source, three systems are most often used ferrous sulfate, ferrous sulfate-cupric sulfate, and ceric sulfate. Dosimeters of these solutions are prepared by filling 5-ml. chemical-resistant glass ampoules with approximately 5 ml. of solution and flame-sealing the ampoules. The ampoules are then arranged in phantoms of Masonite or similar materials (Figure 13) to simulate the food items. These phantoms are placed in containers similar to those used for food products, and arranged in the conveyor carrier in which they are transported into the irradiation cell. Because of the upper dose limit of the ferrous sulfate and ferrous sulfate-cupric sulfate dosimeters (40,000 and 800,000 rads, respectively), these systems can be used only to establish the dose rate in the facility and not to monitor the total dose during food irradiation. The ceric dosimeter which... 

Pyrene and naphthalene were purified by zone refinement for more than 130 passes (Bridgmen method). After such purification the central part of the glass ampoule was extracted and used in the sample preparation. Drop coating of the pyrene (naphthalene) with SWNT suspension in toluene on a quartz substrate was used to form a thin film for Raman measurements. The film was deposited onto the quartz substrate from nanotube suspension in toluene (0.1 mg/mL) and from suspension of nanotube with pyrene (or naphthalene) after short sonication (20 minutes 44 kHz). The weight ratio was 1 1 and 1 4 for mixture with pyrene (samples PI and P2, respectively) and 1 1 with naphthalene (sample N). 

Gd Cg2 was generated by arc discharge using a Gd-graphite rod and isolated by a multistage HPLC technique SWCNT bundles were prepared by pulsed-laser evaporation. The doping of Gd C82 into the inner hollow space of SWCNTs was carried out in a sealed glass ampoule at 500 °C for 24 h. Prior to the introduction of SWCNTs to the ampoule, the SWCNTs were heated in dry air at 420 °C for 20 min [267]. 

Deuterated trifluoroacetic acid was prepared by hydrolyzing a slight excess of trifluoroacetic anhydride with D20. The product was purified by distillation and stored under vacuum in sealed glass ampoules until needed. The isotopic purity was estimated from NMR measurements to be at least 95%. 

The anionic ring-opening copolymerization of hexamethyl-cyclotrisiloxane (Dj) with 2,4,6-trivinyl-2,4,6-trimethyl-cyclotrisiloxane (Vj) was performed under dry Nj atmosphere in a glass ampoule equipped with a teflon stopcock. All other reactions, except the preparation of Pt(0)-[poly(vinylmethyl-co-dimethyl)siloxane]-carbosilane complexes, were performed using standard Schlenk s or syringe techniques under an atmosphere of argon. 

Materials. Poly(3-butenyltrimethylsilane sulfone) (PBTMSS) was synthesized by free-radical copolymerization of 3-butenyltrimethylsilane with liquid sulfur dioxide (molar ratio 1 9) initiated with azobisisobutyronitrile (AIBN) at 35X in a sealed glass ampoule. The detailed preparation procedure and properties of this copolymer have been reported elsewhere. (7 3)... 

---