Column diameter INDEX

The optimized parameters of problem 6.13 are listed in the third column of table 6.5. By comparing the TAC of both approaches, it can easily been inferred that the simultaneous optimization of both spatial and control structures leads to a cheaper and more controllable process than that obtained via the conventional sequential strategy. Although the relative difference between both economic indexes is fairly small, the accumulative cost saving sums up to 0.2 million euros per year. This cost reduction is predominantly originated from the reduced column diameter and smaller reboiler. 

Bromine (128 g., 0.80 mole) is added dropwise to the well-stirred mixture over a period of 40 minutes (Note 4). After all the bromine has been added, the molten mixture is stirred at 80-85° on a steam bath for 1 hour, or until it solidifies if that happens first (Note 5). The complex is added in portions to a well-stirred mixture of 1.3 1. of cracked ice and 100 ml. of concentrated hydrochloric acid in a 2-1. beaker (Note 6). Part of the cold aqueous layer is added to the reaction flask to decompose whatever part of the reaction mixture remains there, and the resulting mixture is added to the beaker. The dark oil that settles out is extracted from the mixture with four 150-ml. portions of ether. The extracts are combined, washed consecutively with 100 ml. of water and 100 ml. of 5% aqueous sodium bicarbonate solution, dried with anhydrous sodium sulfate, and transferred to a short-necked distillation flask. The ether is removed by distillation at atmospheric pressure, and crude 3-bromo-acetophenone is stripped from a few grams of heavy dark residue by distillation at reduced pressure. The colorless distillate is carefully fractionated in a column 20 cm. long and 1.5 cm. in diameter that is filled with Carborundum or Heli-Pak filling. 4 hc combined middle fractions of constant refractive index are taken as 3-l)romoaccto])lu iu)nc weight, 94 -100 g. (70-75%) l).p. 75 76°/0.5 mm. tif 1.57,38 1.5742 m.]). 7 8° (Notes 7 and 8). 

Fused silica capillaries are the most popular capillaries and are commercially available with internal diameters ranging from 10 to 200 pun, although the most commonly used capillary dimensions are 25, 50, and 75 /xm I.D. and 350-400 /xm O.D. To minimize distorting refractive index effects and light scattering with on-column optical detection, the ratio of the outer... 

Chromatographic System Use a liquid chromatograph equipped with a refractive index detector that is maintained at a constant temperature and a 9-mm x 30-cm column packed with a strong cation-exchange resin, about 9 pm in diameter, consisting of sulfonated cross-linked styrene-divinylbenzene copolymer in the calcium form (Aminex HPX-87c, or equivalent). Maintain the column temperature at 85° + 0.5°, and the flow rate of the Mobile Phase at about 0.5 mL/min. Chromatograph the Standard Preparation, and record the peak responses as directed under Procedure. Replicate injections show a relative standard deviation not greater than 2.0%. 

Figure 2 Frontal zone profile of electroosmotic flow in packed capillary column. The capillary column was packed with silica gel (particle diameter 5 pm). The medium was cyclohexanol. As cyclohexanol and silica gel have similar refractive indexes, the column looked transparent. The lower photo was taken 31 s after the upper one.

Column. 2.5% SE-30 on 80-100 mesh Chromosorb G (acid-washed and dimethyldichlorosilane-treated), 2 m X 4 mm internal diameter glass column. It is essential that the support is fully deactivated. Column Temperature. Normally between 100° and 300°. As an approximate guide, the temperature to use is the retention index —10. 

If the solute is assumed to be eluted at a (k ) of 1 from a column 15 cm long, 4.6 mm in diameter and packed with 5 m particles, then this would indicate a sensitivity in terms of concentration of approximately 2 x 10 g/ml, which is equivalent to the response of a very sensitive refractive index detector. The great advantage of the detector, however, is its catholic response and that its output is linearly related to the mass of solute present. 

The molecular weight distribution was determined by gel permeation chromatography (GPC) using a Waters 510 pump with refractive index detector. The separation was performed using two columns in series Styragel HR 4 and HRl with 5 pm particle diameter. THE was used as the eluent at a flow rate of 1 ml/min. The biooil samples were dissolved in THE at a concentration of 2 g/1. The GPC columns were calibrated using polystyrene standards of 400, 600, 760, 800, 1200, 2000, 2430 and 20700 molecular weights. 

The submitter observed a somewhat higher boiling point (41-42°/15 mm.) and did not report the refractive index of the product. Both the submitter and checkers used a column 20 cm. in length, 12 mm. in diameter, packed with glass helices, and equipped with a partial take-off head. If the fractionation is carefully conducted, the product is sufficiently pure for most polymerization work. The compound should be stabilized with hydroquinone and stored in a cold chest if it is not to be used immediately. 

---