Process Development

Brown, C. L.; Smith, W. M.; Scharmann, W.G.

doi:10.1021/ie50464a043

Cited by 7 publications

(8 citation statements)

References 3 publications

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“…Other gasket materials were softened and disintegrated by the xylidine product, and this resulted in very short service life. Other results of the semicommercial unit operation (corrosion experienced with mixtures of nitroxylenes and xylidines in contact with iron and elimination of heat-unstable sulfur compounds in the product distillation section) have been described (1).…”

Section: Resultsmentioning

confidence: 99%

“…The fundamental reaction involved in the process was the catalytic reduction of the nitro groups in mixed isomeric nitroxylenes (essentially monoderivative) to amine groups, with the evolution of considerable quantities of heat of reaction (1). As the existing commercial hydrogenation equipment available to the Esso Standard Oil Company at its refinery at Baton Rouge, La., was designed for high pressure operation (3000 pounds per square inch gage), laboratory work had been directed toward the development of hydrogenation conditions suitable for use at high pressure, although the reaction could also be readily carried out at low hydrogen pressures.…”

Section: Outline Of Processmentioning

confidence: 99%

“…Responsible for direct operation of the unit in accordance with specified operating conditions Pumping feed stock and product; catching gas and liquid samples Controlling preheat and catalyst temperatures, gas rates, and liquid levels Care of feed pumps and gas circulator; control of feed rates and pressure 1 assistant operator 1 helper Product Distillation Pumping feed and product; catching samples Controlling reboiler and tower temperatures; feed, reboiler, and reflux pumps OPERATION OF PILOT PLANT Operation of the pilot plant was on a continuous basis, 24 hours a day, 7 days a week, interrupted only by temporary shutdowns for catalyst replacement or mechanical changes. Direct operation of the pilot plant was carried out with a total of 7 men per 8-hour shift.…”

Section: Hydrogenation Sectionmentioning

confidence: 99%

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PILOT PLANTS. Production of Xylidines by High Pressure Hydrogenation

Voorhies¹,

Smith²,

Mason³

1948

Ind. Eng. Chem.

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T h i s paper describes the adaptation of a semicommercial scale high pressure hydrogenation pilot plant to the production of approximately 8000 pounds per day of xylidines by the hydrogenation of mixed isomeric nitroxylenes. Included are a description of the process and equipment involved, personnel requirements, types of data taken, and results obtained. Optimum operating data previously obtained i n smaller laboratory soale equipment were checked and found to be essentially satisfactory for larger scale operation. This conclusion was later confirmed by actual commercial operation of the process on a scale approximately twenty times larger than the semicommercial plant scale.OhlPA4NIOS papers (1, 3 ) outline the factors on which the C production of xylidines was based, general development of the Esso Laboratories process for this purpose, and the properties and characteristics of the finished xylidines produced. Work on the nitroxylene hydrogenation process development ( 1 ) was initiated in batch autoclaves of , 1-liter capacity, proceeded through the usual laboratory and semicommercial pilot plant development in continuous units of three different sizes, small, medium, and large (production rates equivalent to approximately 3, 30, and 8000 pounds of xylidines per day), and finally culminated in less than 10 months after the first autoclave runs in the commercial hydrogenation of nitroxylenes to produce the equivalent of 150,000 pounds per day of recoverable specification xylidines.Continuous pilot unit equipment of small and medium size, with production rates equivalent to approximately 3 and 30 pounds of xylidines per day has been described ( 2 ) . This type of equipment is suitable for the laboratory development of a process with respect to catalyst and feed stock testing and the effect of process variables on feed stock conversion, product yields, hydrogen consumption, etc. Because of its relatively small size, however, equipment of this type is usually overdesigned with respect to piping and vessel sizes as compared with commercial scale equipment. In small scale equipment, mass velocities are lower; pressure drop in the system is not as much of a problem. Heat losses, on the other hand, are much greater and, for highly exothermic or endothermic reactions, more nearly isothermal operation may be obtained. Adiabatic conditions, which prevail in commercial high pressure hydrogenation reactors of conventional design, are difficult to approximate in small scale equipment. I n cases where heat of reaction is of significant influence on product yield or even on operating conditions necessary to satisfactory operation of a given process, it is difficult to predict the results to be obtained in commercial scale operation based on laboratory scale operation alone.

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Section: Resultsmentioning

confidence: 99%

Section: Outline Of Processmentioning

confidence: 99%

Section: Hydrogenation Sectionmentioning

confidence: 99%

See 1 more Smart Citation

PILOT PLANTS. Production of Xylidines by High Pressure Hydrogenation

Voorhies¹,

Smith²,

Mason³

1948

Ind. Eng. Chem.

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“…The catalytic reduction of nitro compounds has been reviewed in several texts (2,8). For preparation in the laboratory, Raney nickel or platinum oxide gives excellent results.…”

Section: Thementioning

confidence: 99%

Low Pressure Hydrogenation of Nitroxylene and Nitroben-zene over Molybdenum Sulfide

Condit¹

1949

Ind. Eng. Chem.

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Nitrobenzene and nitroxylene, over molybdenum sulfide on active carbon, may be reduced to the corresponding amines continuously at atmospheric pressure. The catalyst gradually loses activity by becoming coated with tarry materials formed by condensation of the amine with the nitro compound. The hydrogenation of nitrohenzene is improved by raising the pressure to 400-500 pounds per square inch gage. The optimum temperature is above 300" C. and a large excess of hydrogen is desirable. Under these conditions space rates up to 1.5

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“…Based on a consideration of all of these factors and on manufacturing and raw materials requirements, xylidines are among the most attractive aromatic amines for use in aviation gasolines. This paper presents the results of studies which were conducted primarily to evaluate the xylidines produced by high pressure hydrogenation of nitroxylenes; this process is described in a companion paper (6). Preliminary investigations on the nature of the xylidines produced by high pressure hydrogenation revealed that these materials did not differ significantly from xylidines produced by other processes with respect to properties such as antiknock value and engine performance oharacteristics, solubility in hydrocarbons, and stability of their blends with aviation gasoline.…”

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confidence: 99%