Abstract: A fluid catalytic cracking unit fractionator comprising a fractionator column having a slurry pumparound section and a bottom liquid section. The slurry pumparound section comprises an upper bed and a lower bed each disposed in the fractionator column. The slurry pumparound section further comprises an upper liquid distributor (such as a spray header comprising a plurality of upper nozzles) disposed above the upper bed and configured to distribute liquid from the bottom liquid section onto the upper bed. The slurry pumparound section also comprises a lower liquid distributor (such as a spray header comprising a plurality of lower nozzles) disposed below the upper bed and above the lower bed and configured to distribute liquid from the bottom liquid section onto the lower bed.

Abstract: A process for the purification of isobutene from a C4 stream with at least 1-butene, 2-butene, isobutane and isobutene includes isomerizing 1-butene from a stream of material which is concentrated in isobutane and isobutene obtained from the C4 stream into 2-butene, using a catalyst in an isomerization reactor; supplying a product stream from the isomerization reactor to a rectification column; and providing a stream of material which is concentrated in isobutene. A processing facility is utilized for the purification of isobutene from the C4 stream.

Abstract: This invention relates to a method of separating a multiproduct mixture using a prefractionation/main column arrangement to efficiently separate the multiproduct mixture into the desired individual products. One advantage of the invention is that it can be used to debottleneck an existing series of distillation columns, permitting a capacity expansion to take place without requiring the installation of an entire new train of distillation columns.

Abstract: A method of decomposing a phenol by-product produced in a phenol preparation process, in which acetophenone separated from a distillation column is mixed with tar separated and collected in a decomposition reactor, thereby significantly decreasing viscosity of tar. The decomposition method according to the present invention allows tar to have sufficient viscosity for flowability even at room temperature, whereby transfer and storage of tar may be more smoothly done without using any heating device for transfer of tar.

Abstract: A water purifying and desalination system includes solar concentrators that receive a sunlight and direct the sunlight toward a collection element. The collection element absorbs and converts a solar radiation into thermal energy. A superheater tube enclosed by the heat collection element controls volume flow that partially fills the superheater tube with processed ocean water, which allows steam to escape into a portion of the superheater tube that generates electricity and additional processed ocean water.

Abstract: Provided are a method for preparing an oligomer and an apparatus for preparing the same. The method for preparing an oligomer including: supplying a feed stream including a monomer to a reactor to perform an oligomerization reaction; supplying a first discharge stream from the reactor to a first separation device and supplying a second discharge stream from the reactor to a second separation device; recovering the monomer as an upper discharge stream from the second separation device and supplying a lower discharge stream from the second separation device to a third separation device; and supplying an upper discharge stream from the third separation device to the second separation device.

Abstract: Disclosed is a process for recovering formic acid from a formate ester that allows for recovery of a formic acid product comprising greater than 75 wt. % formic acid. Disclosed is also a process for producing formic acid by carbonylating a carrier alcohol, hydrolyzing the formate ester of the carrier alcohol, and recovering a formic acid product comprising greater than 70 wt. % formic acid. Discloses are carrier alcohols that enable more favorable hydrolysis equilibriums and/or distillation sequences.

Abstract: The present invention generally relates to nanoscale wires and tissue engineering. Systems and methods are provided in various embodiments for preparing cell scaffolds that can be used for growing cells or tissues, where the cell scaffolds comprise nanoscale wires. In some cases, the nanoscale wires can be connected to electronic circuits extending externally of the cell scaffold. Such cell scaffolds can be used to grow cells or tissues which can be determined and/or controlled at very high resolutions, due to the presence of the nanoscale wires, and such cell scaffolds will find use in a wide variety of novel applications, including applications in tissue engineering, prosthetics, pacemakers, implants, or the like. This approach thus allows for the creation of fundamentally new types of functionalized cells and tissues, due to the high degree of electronic control offered by the nanoscale wires and electronic circuits.

Abstract: An extraction tower includes a housing defining a light phase outlet at a top thereof, a heavy phase inlet at an upper portion thereof, a light phase inlet at a lower portion thereof and a heavy phase outlet at a bottom thereof; a heavy phase distributor disposed in the housing and communicated with the heavy phase inlet; a light phase distributor disposed in the housing and communicated with the light phase inlet; a packing layer disposed in the housing and located between the heavy phase distributor and the light phase distributor; and at least one layer of vertical plates disposed in at least one of the packing layers, each layer of the vertical plates comprising at least two vertical plates parallel or cross to each other, each vertical plate disposed in an axial direction.

Abstract: A method and system for controlling a hydrocracker and fractionator reaction loop is disclosed. The method and system utilizes a sidedraw tray within the fractionator distillation zone upon which liquid is collected. This liquid is withdrawn as a sidedraw stream. The withdrawal of the liquid from the sidedraw tray is controlled based on the level of liquid on the sidedraw tray rather than at a set or determined flow rate. The sidedraw stream is separated into a first stream and a product stream. Unlike other processes where the flow rate of the product stream is set and the internal reflux flow rate varies, the method involves fixing the flow rate of the first stream that is returned to the distillation zone of the fractionators with the flow rate of the product stream being set so as to control the liquid level on the sidedraw tray.

Abstract: A system for molecular targeting and separating includes a microwave energy source; a vapor source; a column configured and positioned to receive microwave energy from the microwave energy source and vapor from the vapor source; and a condenser, the condenser in communication with the column, the condenser configured to condense the vapor after the vapor receives the microwave energy.

Abstract: Systems and processes for improving quality and yield of one or more distillate products generated in a distillation column are disclosed. The system comprises a feed inlet distributor that reduces the amount of liquid entrained in vapor rising from the feed zone of the distillation column, a wash zone collection apparatus having an improved design for collecting slop wax falling from a liquid/vapor contacting structure provided in the wash zone, a recirculation subsystem for recirculating at least a portion of the collected slop wax to the top of the wash zone for distribution as wash oil, and a control subsystem. The feed inlet distributor ensures a horizontal fluid flow path free of transverse surfaces thereby minimizing atomization of liquid droplets entrained in vapor in the feed stream.

Abstract: A fermentation liquid feed including water and a product alcohol and optionally CO2 is at least partially vaporized such that a vapor stream is produced. The vapor stream is contacted with an absorption liquid under suitable conditions wherein an amount of the product alcohol is absorbed. The portion of the vapor stream that is absorbed can include an amount of each of the water, the product alcohol and optionally the CO2. The temperature at the onset of the absorption of the vapor stream into the absorption liquid can be greater than the temperature at the onset of condensation of the vapor stream in the absence of the absorption liquid. The product alcohol can be separated from the absorption liquid whereby the absorption liquid is regenerated. The absorption liquid can include a water soluble organic molecule such as an amine.

Abstract: An aromatics complex producing one or more xylene isomers offers a large number of opportunities to conserve energy by heat exchange within the complex. One previously unrecognized opportunity is through providing two parallel distillation columns operating at different pressures to separate C8 aromatics from C9+ aromatics. The parallel columns offer additional opportunities to conserve energy within the complex through heat exchange in associated xylene recovery facilities.

Abstract: Disclosed is a process for improving the efficiency of a combined-cycle power generation plant and desalination unit. The process includes supplying exhaust gases from a gas turbine set used to generate electrical power to a heat recovery steam generator (HRSG) and then directing the steam from the HRSG to a steam turbine set. Salinous water is supplied into an effect of the desalination unit. Steam exhausted from the steam turbine set is utilized in the effect of the desalination unit to produce a distillate vapor and brine from the effect by heat exchange. Additionally, steam is introduced steam from at least one additional heat source from the combined-cycle power generation plant to the effect to increase the mass flow rate of steam into the effect. In one embodiment, the additional heat source is an intercooler heat exchanger. Heated water from the intercooler heat exchanger is provided to a reduced atmosphere flash tank, and the steam flashed in the flash tank is provided to the effect.

Abstract: A method of dehydrating tolylenediamine which includes subjecting tolylenediamine having a water content of 5-40 wt. % to first-stage distillation at a vacuum of 13-101.3 kPa and subjecting the bottoms from the first-stage distillation to second-stage distillation at a vacuum lower than 13kPa.

Abstract: The invention comprises an absorption heat pump to supply energy to a distillation process or an outside process. The streams used to effect the absorption heat pump are to be combined in any case as a feedstream to a conversion process, and energy thus is conserved by avoiding the necessity of reseparating the streams.

Abstract: A process for treatment of an aqueous stream to produce a low solute containing distillate stream and a high solute/solids containing blowdown stream utilizing a method to increase the efficiency of an evaporator while providing an essentially scale free environment for the heat transfer surface. Multi-valent ions and non-hydroxide alkalinity are removed from aqueous feed streams to very low levels and then the pH is increased preferably to about 9 or higher to increase the ionization of low ionizable constituents in the aqueous solution. In this manner, species such as silica and boron become highly ionized, and their solubility in the concentrated solution that is present in the evaporation equipment is significantly increased. The result of this is high allowable concentration factors and a corresponding increase in the recovery of high quality reusable water with essentially no scaling.

Abstract: An azeotropic distillation method, comprising a reaction step, a distillation step for separating and refining a reaction product, and a recovery step for collecting a reactant after the distillation step; wherein at least one component constituting the reactant in the reaction step can act as an entrainer for the azeotropic distillation in the distillation step; and a portion of the reactant capable of acting as the entrainer is supplied to the distillation step.

Abstract: An apparatus and process for the separation of refrigerant mixtures is provided. The apparatus includes a first distillation column, a first condenser, and a first collection vessel. The apparatus also includes a sorter vessel that includes a sorter agent, wherein the sorter vessel is fluidly connected to the first distillation column.

Abstract: The invention disclosed is an apparatus and method for the recovery of acetic acid, azeotropic agent, extraction agent, re-usable water and other reaction products such as p-toluic acid, from an aqueous stream generated during a terephthalic acid production process, having superior energy efficiency and reduced water consumption.

Abstract: Systems and processes for improving quality and yield of one or more distillate products generated in a distillation column are disclosed. The system comprises a feed inlet distributor that reduces the amount of liquid entrained in vapor rising from the feed zone of the distillation column, a wash zone collection apparatus having an improved design for collecting slop wax falling from a liquid/vapor contacting structure provided in the wash zone, a recirculation subsystem for recirculating at least a portion of the collected slop wax to the top of the wash zone for distribution as wash oil, and a control subsystem. The feed inlet distributor ensures a horizontal fluid flow path free of transverse surfaces thereby minimizing atomization of liquid droplets entrained in vapor in the feed stream.

Abstract: A method for concentrating effectively the heavy nitrogen isotope 15N to 50 atom % or more in which 14N15N and/or 15N2, which are molecules containing a heavy nitrogen isotope of 15N, are concentrated by distilling successively nitrogen N2 using plural distillation columns T1 to T4 each of which includes at least one condenser C1 to C4 and at least one reboiler R1 to R4 and is arranged in series, and a part of nitrogen in the distillation is drawn out to be subjected to isotope scrambling in an isotope scrambler S1, and nitrogen after the isotope scrambling is returned to the distillation to produce nitrogen N2 with a 15N concentration of 50 atom % or more.

Abstract: A method for the separation of hydrocarbon compounds utilizing a dividing wall distillation column is described. The dividing wall distillation column enables one or more side draw stream to be removed from the dividing wall distillation column in addition to an overhead stream and a bottoms stream.

Abstract: A water-soluble organic material condensation apparatus equipped with a distillation column for distilling an aqueous solution of a water-soluble organic material, wherein a vapor generated at the top of the distillation column or a condensed liquid from the vapor is introduced to a device other than the distillation column which has the function to separate water from the water-soluble organic material to thereby condense the water-soluble organic material through separating water and then the condensed water-soluble organic material is recycled to the distillation column. The device other than the distillation column is desirably a separating film such as a zeolite film. The apparatus is improved in the operation of the upper portion of the condensation section of the distillation column and allows energy savings during distillation.

Abstract: The object of the present invention is to provide a method for concentrating effectively the heavy nitrogen isotope 15N to 50 atom % or more. In order to achieve the object, the present invention provides a method for concentrating a heavy nitrogen isotope 15N, in which 14N15N and/or 15N2, which are molecules containing a heavy nitrogen isotope of 15N, are concentrated by distilling successively nitrogen N2 using plural distillation columns T1 to T4 each of which comprises at least one condenser C1 to C4 and at least one reboiler R1 to R4 and is arranged in series, and a part of nitrogen in the distillation is drawn out to be subjected to isotope scrambling in an isotope scrambler S1, and nitrogen after the isotope scrambling is returned to the distillation to produce nitrogen N2 with a 15N concentration of 50 atom % or more.

Abstract: A novel method for connecting multiple existing columns which are retrofitted into vapor-liquid contacting devices with trays or packings suitable for the operation of a three-phase (vapor-liquid-liquid) extractive distillation column for aromatics recovery. The retrofitted columns are connected by a vapor transfer line to transfer the vapor phase from the top of the lower column to the bottom of the upper column, and by a liquid transfer line to transfer the liquid phase from the bottom of the upper column to the top of the lower column of the three-phase extractive distillation column.

Abstract: This invention is an improved distillation sequence for the separation and purification of ethylene from a cracked gas. A hydrocarbon feed enters a C2 distributor column. The top of the C2 distributor column is thermally coupled to an ethylene distributor column, and the bottoms liquid of a C2 distributor column feeds a deethanizer column. The C2 distributor column utilizes a conventional reboiler. The top of the ethylene distributor is thermally coupled with a demethanizer column, and the bottoms liquid of the ethylene distributor feeds a C2 splitter column. The ethylene distributor column utilizes a conventional reboiler. The deethanizer and C2 splitter columns are also thermally coupled and operated at a substantially lower pressure than the C2 distributor column, the ethylene distributor column, and the demethanizer column. Alternatively, a hydrocarbon feed enters a deethanizer column.

Abstract: A mixture comprising at least 1,1,1,3,3-pentafluoropropane and 1,1,1-trifluoro-3-chloro-2-propene is subjected to a distillation operation, and thereby, a distillate comprising an azeotropic composition consisting substantially of 1,1,1,3,3-pentafluoropropane and 1,1,1-trifluoro-3-chloro-2-propene is obtained and a bottom product comprising 1,1,1,3,3-pentafluoropropane or 1,1,1-trifluoro-3-chloro-2-propene which each is separated and purified.

Abstract: Disclosed herein are methods for the recovery of an organic acid, such as a heat stable lactic acid, from a feed stream which contains at least one of an organic acid amide, an organic acid ammonium salt, or an alkylamine-organic acid complex. The feed stream is mixed with at least one azeotroping agent. The azeotroping agent is a hydrocarbon capable of forming at least one azeotrope with the organic acid that is produced by the thermal decomposition of the amide, ammonium salt, or complex in the feed stream. Preferably the azeotrope is a heteroazeotrope. The mixture of the feed stream and the azeotroping agent is heated to produce a vapor stream. The azeotrope is a component of the vapor stream. The vapor stream can be condensed to a liquid stream, and the organic acid is recovered in the liquid stream that is produced. When the azeotrope is a heteroazeotrope, the vapor stream can be condensed into a liquid stream, which can be separated into a first phase and a second phase.

Abstract: The invention relates to a method for separating and purifying an aqueous mixture that mainly consists of acetic acid, formic acid and high-boiling substances by extraction with a solvent in a cyclic process. The inventive method is characterized in that the flow of raffinate is fed to a solvent stripping column (11) with the major part of the water in order to remove the water from the cycle. The flow of extract is fed to a solvent recovery distillation column (8). In a first step, a mixture (A) that consists of water and solvent, is separated by overhead distillation. A mixture (B) that consists of acetic acid, formic acid and high-boiling substances is separated via a sump. Once the formic acid is removed in a column (29), mixture (B) is separated in an acetic acid distillation column to give pure acetic acid and high-boiling substances.

Abstract: For the purification of the norbornene obtained by the reaction of dicyclopentadiene or cyclopentadiene and ethylene, the crude reaction mixture containing light impurities having boiling temperatures lower than that of norbornene; medium-heavy impurities having the boiling temperatures between that of norbornene and that of ethylnorbornene; and heavy impurities containing ethylnorbornene and compounds boiling higher than ethylnorbornene, boiling temperatures greater than that ethylnorbornene, a first distillation of the crude reaction mixture is carried out in a tailing column (C1), removing a portion of the heavy impurities and a portion of the medium-heavy impurities; then a second distillation of the crude mixture, thus tailed, is carried out in a topping column (C2), removing the light impurities; and a third distillation of the mixture, thus topped, is subsequently carried out in a tailing column (C3), removing the remainder of the heavy and medium-heavy impurities.

Abstract: A process for the selective hydrogenation of the methyl acetylene and propadiene (MAPD) in a propylene rich stream is disclosed wherein the selective hydrogenation is carried out stepwise (a) first in a single pass fixed bed reactor and then (b) in a distillation column reactor containing a supported PdO hydrogenation catalyst which serves as a component of a distillation structure. Conversion and selectivity to propylene in improved over the use of the single pass fixed bed reactor alone.

Abstract: An extractive distillation tower 4 supplied with a feedstock containing butadiene and a solvent and for distilling the feedstock to separate and purify the butadiene.

Abstract: A heat-deteriorative compound contained in a liquid mixture is refined by a distillation procedure using a distillation column in which a vapor fraction and a liquid fraction containing the heat-deteriorative compound are generated from the liquid mixture, and a liquid film-falling reboiler in which the liquid fraction falls in the form of liquid films along inner surfaces of a plurality of vertical heat-conductive pipes at a Reynolds number (Re) of 700 to 10,000 and heated to a temperature lower than the heat-deterioration temperature of the heat deteriorative compound to such an extent that 1 to 15% by weight of the liquid fraction is evaporated per pass through the reboiler, the heated liquid fraction being returned into the distillation column to generate the vapor fraction from the liquid mixture fed into the distillation column.

Abstract: Processes for the purification and color stabilization of crude maleic anhydride by distillation in a batch or continuous distillation column.

Abstract: Acetals are produced from the reaction of aldehydes and alcohols, e.g. methylal by the reaction of methanol and formaldehyde, by the reaction in a reaction distillation column of the alcohol and aldehyde in the presence of a catalyst and the concurrent fractional distillation of the reaction mixture to separate the reaction products, water and acetal.

Abstract: A process for the purification of recovered or regenerated phosphorus oxychloride contaminated by reactive organic compounds, by reacting the contaminated phosphorus oxychloride with from 0.1 to 5% by weight of an organic amine, having 1 or 2 tertiary N-atoms and a boiling point above the boiling point of phosphorus oxychloride, at the boiling temperature of the reaction mixture and subsequently carrying out fractional distillation at atmospheric pressure to obtain purified phosphorus oxychloride.

Abstract: There is provided a purification process for dimethoxymethylsilane in which a mixture containing dimethoxymethylsilane and methanol is subjected to a first distillation step in which the mixture is distilled in the presence of methyl formate or methoxytrimethylsilane so that a distillate fraction containing methanol and methyl formate or methoxytrimethylsilane is distilled off and a balance fraction containing dimethoxymethylsilane and methanol is discharged, the amount of methanol in the balance fraction being substantially reduced relative to that of the mixture.

Abstract: A process for the purification of raw acetone deriving from processes for the production of phenol acetone, impurity mainly due to cumene, water, aldehydes and methanol, the steps of:feeding the stream of raw acetone coming from the primary fractionation of a plant for the production of phenol and acetone to a first distillation column to which a solution of sodium hydroxide at 2% is also fed;sending the stream at the head of the first column, containing of acetone, water and cumene to a second column to which the extractive solvent triethyleneglycol is also fed;recovering substantially anhydrous acetone from the head of the second column;feeding the bottom product of the second column, containing triethyleneglycol, water, cumene and acetone to a third distillation column in which an azeotropic mixture of water and cumene is recovered from the head and anhydrous triethyleneglycol from the bottom;sending the azeotropic mixture of water and cumene to a decanter in which a water phase is separated, containing ac

Abstract: A process including a first stage wherein a feed gas stream containing acrolein originating, for example from the gas-phase oxidation of propylene to acrolein, is fractionated into a gaseous effluent and a liquid stream in a cooling column operating such that the temperature of the liquid stream at the bottom of the column is lower than or equal to the condensation temperature of the feed gas stream, the difference in temperature not exceeding 20.degree. C. and, a second stage, wherein the gaseous effluent is condensed at a temperature that is lower than 20.degree. C., to give a liquid fraction and a purified gaseous fraction, is disclosed. An apparatus for carrying on the purification process is also disclosed.

Abstract: The production of high purity benzene and high purity toluene is obtained by utilizing the initial gas separating column for the treatment of the aromatic containing starting material as a separating column for separating a benzene rich from a toluene rich component. The benzene rich component is subject directly to distillation while the toluene is subject to predistillation to separate high boiling components and only then to extractive distillation is distilled to separate the high purity benzene from the high purity toluene.

Abstract: The invention is a process for reducing capital and energy costs in ethylene recovery. Moderate pressure processing and thermally coupled fractionation steps are achieved through the use of integrator columns. Ethylene separation from cracked gas originating from ethane through gas oil feeds can now be done with thermodynamically efficient fractionation at capital cost competitive with low efficiency designs. Acetylene hydrogenation may be done before demethanization where desired, and dephlegmation is preferred to accomplish high-efficiency rectification of hydrogen and methane from ethylene. Open loop heat pumps can optionally be incorporated into the ethane/ethylene splitter fractionation step, whose desirability is controlled by optimization of capital and energy costs.

Abstract: An extractive distillation agent of 1-propanol is fed to an extractive distillation column used for the distillation of propylene oxide contaminated with water, acetone and methanol to obtain an overhead distillate fraction of essentially anhydrous propylene oxide contaminated with reduced quantities of acetone and methanol, and a heavier bottoms distillation fraction containing substantially all of the 1-propanol, water and acetone, some of the methanol and heavier by-products of propylene oxide formed in the distillation column.

Abstract: The present invention provides a method for removing an organic compound in water at a high efficiency by separating an organic compound, particularly such an organic chlorine compound as 1,2-dichloroethane, carbon tetrachloride and chloroform dissolved in water or forming two liquid phases with water from a water phase, by the steps of:(i) charging water containing an organic compound into a first distillation column for conducting distillation or steam distillation to take the organic compound and water out of the top of the first distillation column and to obtain a bottom liquor containing the organic compound at a lower content from the bottom of the first distillation column, and(ii) charging the bottom liquor of the first distillation column into a second distillation column operated at a pressure lower than that in the first distillation column for conducting distillation, preferably flashing under reduced pressure, to take a gas distillate containing a large amount of the organic compound out of the t

Abstract: Volatile acids containing metal salt impurities, such as metal pickling solutions-are regenerated by a process in which the acid is subjected to sulfuric acid distillation. Resulting volatile acid vapor is condensed and recycled to the pickle tank, while the residual acid mixture is treated in an acid sorption unit, preferably of the acid retardation type. Acid sorbed in the acid sorption unit is periodically eluted with water and recycled, while metal impurities are rejected in a deacidified by-product solution.

Abstract: Benzene and other aromatics are separated from a stream of mixed hydrocarbons containing both aromatics and non-aromatics by extractive distillation with a solvent system containing dimethyl sulfoxide and optionally a co-solvent, preferably water, followed by distillation stripping of the aromatics from the enriched solvent system, and recycle of the lean solvent system to the extractive distillation step.

Abstract: Where side stream distillate strippers are used in the distillation of hydrocarbons, the required size of the distillation column and the amount of stripping gas or vapor required are reduced by passing components stripped from the distillates through a plurality of strippers in series, rather than directly back to the distillation zone.

Abstract: A method of recovering a solvent from a mother liquor in a system in which the mother liquor also contains non-volatile matter, volatile solute and volatile solvent, and the solute concentration is low, in which a heat pump distilling column (first column) is so operated as to work only as a concentrating section of a distilling column by feeding a mother liquor to the column bottom of the heat pump distilling column, contact of non-volatile matter with the concentrating section is prevented and the column bottom liquor is sent to an evaporator so as to separate the non-volatile matter by the evaporator, thereafter, a vapor from the evaporator is fed to a distilling column (second column), and distillates of first and second columns and bottoms of the second column are withdrawn as the products. The procedures described above are carried out under specific operation conditions.

Abstract: A process for separating phenol obtained by the decomposition of cumene hydroperoxide from high boiling impurities, includes the following steps:a) feeding phenol rectification bottoms comprising phenol, acetophenone, cumylphenol, alpha-methylstyrene dimers and high boiler residues to a first phenol freeing distillation column A;b) feeding concentrated bottoms with substantially reduced phenol content from column A to a second residue concentration distillation column B;c) withdrawing a stream rich in compounds boiling between phenol and residue, particularly cumylphenol, from said column B from a point below the feed and returning at least a portion of said stream to said column A at a point above the feed;d) recovering overheads from column A comprising at least 95 weight percent phenol; ande) recovering acetophenone-rich overheads from column B comprising at least 70 weight percent acetophenone.