[go: up one dir, main page]

WO1996010009A1 - Procede de commande, par l'analyse dans l'infrarouge proche ou moyen, de la conversion d'un ester de polyol - Google Patents

Procede de commande, par l'analyse dans l'infrarouge proche ou moyen, de la conversion d'un ester de polyol Download PDF

Info

Publication number
WO1996010009A1
WO1996010009A1 PCT/US1995/013108 US9513108W WO9610009A1 WO 1996010009 A1 WO1996010009 A1 WO 1996010009A1 US 9513108 W US9513108 W US 9513108W WO 9610009 A1 WO9610009 A1 WO 9610009A1
Authority
WO
WIPO (PCT)
Prior art keywords
polyol
acid
mid
acids
ester product
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/US1995/013108
Other languages
English (en)
Inventor
Larry Oliver Jones
Joe Randall Noles, Jr.
Robert John Louis Chimenti
Howard L. Fang
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
ExxonMobil Chemical Patents Inc
Original Assignee
Exxon Chemical Patents Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Exxon Chemical Patents Inc filed Critical Exxon Chemical Patents Inc
Priority to AU38311/95A priority Critical patent/AU3831195A/en
Publication of WO1996010009A1 publication Critical patent/WO1996010009A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J19/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
    • B01J19/0006—Controlling or regulating processes
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J19/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
    • B01J19/0006—Controlling or regulating processes
    • B01J19/0013—Controlling the temperature of the process
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J19/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
    • B01J19/18—Stationary reactors having moving elements inside
    • B01J19/1862—Stationary reactors having moving elements inside placed in series
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C67/00—Preparation of carboxylic acid esters
    • C07C67/08—Preparation of carboxylic acid esters by reacting carboxylic acids or symmetrical anhydrides with the hydroxy or O-metal group of organic compounds
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J2219/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
    • B01J2219/00049—Controlling or regulating processes
    • B01J2219/00051—Controlling the temperature
    • B01J2219/00074—Controlling the temperature by indirect heating or cooling employing heat exchange fluids
    • B01J2219/00076—Controlling the temperature by indirect heating or cooling employing heat exchange fluids with heat exchange elements inside the reactor
    • B01J2219/00083—Coils
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J2219/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
    • B01J2219/00049—Controlling or regulating processes
    • B01J2219/00186—Controlling or regulating processes controlling the composition of the reactive mixture

Definitions

  • the present invention relates generally to the conversion of polyols in the presence of excess acids to their corresponding esters.
  • a key step in this process is to measure the near or mid-infrared spectra of the reaction mixture and to estimate the degree of conversion from the spectra using a multivariate model. Knowledge of, for example, the initial acid concentration in the reaction mixture will also enable one to predict the ratio of reactants charged at the outset into the reaction vessel.
  • near or mid-infrared analysis may also be used in other parts of the polyol ester process, i.e., it may be used to predict other important process control variables such as water concentration, polyol concentration, acid concentration, and/or other compositional properties of the reaction, stripping and run-down steps.
  • the water which is formed during esterification be removed as rapidly as possible. It is known that water has a detrimental effect upon the rate of conversion. Conventionally, water has been removed by carrying out the reaction using an entrainer which forms an azeotrope having a boiling point that is lower than that of either component of the reaction. However, in many cases water can be removed without the need for an entrainer by, for example, co-distillation with one of the low boiling point reactants. If the resulting ester has a boiling point well above 100°C at atmospheric pressure, then the reaction temperature can be adjusted such that no liquid medium capable of forming an azeotrope is required. It is also critical that the concentration of water be known at all times in order to fine tune the esterification process.
  • polyol esters e.g., esters made from aliphatic acids and trimethylol propane (TMP)
  • TMP trimethylol propane
  • the commercially desirable conversions are at greater than 98%.
  • the excess acid is generally removed by a combination of stripping or neutralizing and washing.
  • the conversion level is determined by the product specification for the hydroxyl number, a measure of the number of residual hydroxyl groups in the ester. Typical product applications require conversions of about 98.5% of the original number of hydroxyl groups in the polyol.
  • Table 1 sets forth the various analytical measurements which are required during polyol ester synthesis, the current analytical methods used to obtain those measurements, the frequency with which the measurements are needed, and the time required to perform such measurements.
  • the measurement of low levels of water in organic solvents has previously been accomplished by gas chromatography, solid state capacitance sensors, photometers and Karl Fischer titration.
  • the Karl Fischer titration is labor intensive and requires the most rigorous of laboratory skills.
  • the photometer is the simplest of the technologies but lacks specificity and therefore frequently gives erroneous readings.
  • the gas chromatography although more specific than the photometer is more maintenance intensive, requires sample lines, and has longer lag times.
  • the present inventors have discovered that the use of a near or mid- infrared analyzer will allow the use of a single spectrum measurement to predict, on a real-time basis, chemical and physical properties of the esterification reaction mixture in the presence of large amounts of carboxylic acids (5 to 20 weight %).
  • the compositional properties of the various product streams that exit the reaction mixture into the stripper and run-down tanks can also be accurately predicted using the analyzer of the present invention.
  • reaction cycle time reduction due to instantaneous conversion measurement allows for: (a) reaction cycle time reduction due to instantaneous conversion measurement; (b) reduced fixed costs such as manpower wages; and (c) consistent product quality through consistent conversion and an ability to adjust reaction mixtures (i.e., by measurement of compositional properties and through addition of fresh acids) during the course of the reaction to correct for compositional properties due to slight processing variations from batch to batch.
  • reaction mixtures i.e., by measurement of compositional properties and through addition of fresh acids
  • instantaneous knowledge of water concentration in the esterification mixture will allow real-time monitoring of water removal efficiency.
  • a process for the esterification of a polyol with an acid which comprises the following steps: adding a polyol and at least one acid to a reaction vessel to form a reaction mixture; heating the reaction mixture and maintaining a pressure sufficient to convert the polyol and acid to a polyol ester and removing water as vapor; monitoring the reaction mixture by means of near infrared or mid-infrared analysis such that the conversions and/or concentrations of water, acids, and/or polyol, and/or other compositional properties of the reaction mixture in the presence of excess carboxylic acid can be predicted; and adjusting the reaction conditions of the esterification reaction, the concentration of the acids, and/or the concentration of the polyol.
  • the aforementioned are adjusted depending upon the degree of conversions, concentrations of water, acids, and/or polyol, and/or the other compositional properties in the reaction mixture as predicted by the near or mid-infrared analysis.
  • the esterification process preferably includes the additional steps of removing excess acid from the polyol ester product by stripping (e.g., steam or nitrogen) and recycling the excess acid to the reaction vessel, monitoring the stripped ester product by means of near infrared or mid-infrared analysis and adjusting (1) the operating conditions of the stripper (e.g., temperature, pressure and steam rate), (2) the reaction conditions of the esterification reaction, and or (3) the concentrations of the acids and/or polyols. The adjustments are made depending upon the degree of the conversions, concentrations of water, acids, and/or polyol, and/or other compositional properties in the stripped ester product.
  • stripping e.g., steam or nitrogen
  • the esterification process may include the steps of sending an enriched or concentrated polyol ester product to a run-down tank, monitoring the enriched polyol ester product by means of near infrared or mid- infrared analysis and adjusting (1) the operating conditions of the stripper (e.g., temperature, pressure and steam rate), (2) the reaction conditions of the esterification reaction, and/or (3) the concentrations of the acids and/or polyols. These adjustments depend upon degree of the conversions, concentrations of water, acids, and/or polyol, and/or other compositional properties in the enriched polyol ester product.
  • the other compositional properties of the enriched polyol ester product are selected from the group consisting of: viscosity, viscosity index, flash point, cloud point, pour point and OCS stability.
  • Fig. 1 is a graph comparing the near infrared abso ⁇ tion spectra of trimethylol propane (TMP) and linear C 7 carboxylic acid mixtures;
  • Fig. 2 is a graph showing the dependence of absorbance on weight percent of TMP
  • Fig. 3 is a graph showing the standard errors of estimate (SEE) for estimating the weight percent of TMP in the mixtures as a function of the wavelength;
  • Figs. 4 and 5 are graphs showing mid-IR absorption spec * ra in the 400 to 4600 cm '1 range;
  • Fig. 6 is a graph plotting the standard errors of estimate for the TMP and C7 acid reaction mixture using mid-IR;
  • Fig. 7 is a graph plotting the standard errors of estimate for the TMP and C 7 acid reaction mixture using near-IR;
  • Fig. 8 is a graph showing the spectra of the di-ester, tri-ester, and acid mixture of C ⁇ , C 7 , C 8 , and C10 linear acids;
  • Fig. 9 is a schematic representation of the esterification process according to the present invention
  • Fig. 10 is a flow chart of the near infrared analysis used to monitor and adjust the esterification process of the present invention
  • Fig. 11 is a graph plotting predicted versus actual values for tetra-ester conversion
  • Fig. 12 is a graph plotting predicted versus actual values for hydroxyl conversion
  • Fig. 13 is a graph plotting predicted versus actual values for acid mole
  • Fig. 14 is a graph plotting predicted versus actual values for acid #.
  • Fig. 15 is a graph plotting predicted versus actual values for water ppm.
  • the conversion of polyols and acids to polyol esters typically comprises: (a) the esterification of the starting acid with a polyol, and optionally, a catalyst, at a temperature and pressure which permits boiling of the mixture in a reactor; (b) monitoring the reaction mixture by near or mid- infrared analysis such that the conversions and/or concentrations of water, acids, and/or polyol, and/or other compositional properties of the reaction mixture in the presence of excess carboxylic acid can be predicted; and (c) adjusting the reaction conditions and/or the concentrations of the acids and/or polyol in the response to the predictions obtained in step (b) above.
  • the esterification process may also include one or more of the following steps: removal of excess acid by stripping (e.g., nitrogen or steam); addition of absorbents such as alumina, silica gel, activated carbon, clay and/or filter aid to the reaction mixture following esterification before further treatment, but in certain cases absorbent treatment may occur later in the process following steam stripping and in still other cases the absorbent step may be eliminated from the process altogether; addition of water to hydrolyze the catalyst (if present); filtration of solids from the ester mixture containing the bulk of the excess acid used in the esterification reaction; removal of excess acid by steam or nitrogen stripping under vacuum and recycling of the acid to the reaction vessel; and removing solids from the stripped ester in a final filtration and transporting to a run-down tank for storage.
  • stripping e.g., nitrogen or steam
  • absorbents such as alumina, silica gel, activated carbon, clay and/or filter aid to the reaction mixture following esterification before further treatment, but in certain cases absorbent treatment may
  • near infrared analysis can be used to predict the polyol conversion to 0.02%, and di-ester and tri-ester formation to 0.04% and 0.5%, respectively.
  • the mid-infrared spectra can be used to predict the polyol and water concentrations during the esterification reaction.
  • neopentanoic acid neoheptanoic acid, neo-octanoic acid, neononanoic acid, neodecanoic acid, 2-ethyl hexanoic acid, oxo-heptanoic acid (i.e., a mix of isomers derived from oxonation/oxidation of hexenes), oxo-decanoic acid (i.e., a mix of isomers derived from oxonation/oxidation of mixed nonenes), oxo- octanoic acid (i.e., a mix of isomers derived from oxonation/oxidation of mixed heptenes), 3,5,5-trimethylhexanoic acid, linear C 5 -C ⁇ 8 alkanoic acids, and blends thereof.
  • oxo-heptanoic acid i.e., a mix of isomers derived from oxon
  • Polyols i.e., polyhydroxy compounds
  • polyhydroxy compounds are represented by the general formula:
  • R is an alkyl, alkenyl or aralkyl hydrocarbyl group and n is at least 2, and can be used in place of the mono alcohols when polyol esters are desired.
  • the hydrocarbyl group may contain from about 2 to about 20 or more carbon atoms, and the hydrocarbyl group may also contain substituents such as chlorine, nitrogen and/or oxygen atoms.
  • the polydroxyl compounds generally will contain from about 2 to 10 hydroxy groups and more preferably from about 2 to 6 hydroxy groups.
  • the polyhydroxy compound may contain one or more preferably from about 2 to 6 hydroxy groups.
  • the polyhydroxy compound may contain one or more oxyalkylene groups and, thus, the polyhydroxy compounds include compounds such as polyethe ⁇ olyols.
  • the number of carbon atoms and number of hydroxy groups contained in the polyhydroxy compound used to form the carboxylic esters may vary over a wide range.
  • the following alcohols are particularly useful as polyols: neopentyl glycol, 2,2-dimethylol butane, trimethylol ethane, trimethylol propane, trimethylol butane, mono-pentaerythritol, technical grade pentaerythritol, dipentaerythritol, ethylene glycol, propylene glycol and polyalkylene glycols (e.g., polyethylene glycols, polypropylene glycols, polybutylene glycols, etc., and blends thereof such as a polymerized mixture of ethylene glycol and propylene glycol).
  • polyalkylene glycols e.g., polyethylene glycols, polypropylene glycols, polybutylene glycols, etc., and blends thereof such as a polymerized mixture of ethylene glycol and propylene glycol.
  • polyol esters such as, neopolyol esters
  • the polyol or polyol mixture is preferably technical grade pentaerythritol (PE), trimethylol propane (TMP), and neopentylglycol each which can be admixed with monopentaerythritol and/or trimethylol propane or other neopolyols.
  • PE pentaerythritol
  • TMP trimethylol propane
  • neopentylglycol each which can be admixed with monopentaerythritol and/or trimethylol propane or other neopolyols.
  • the preferred acid component is typically a mixture of straight chain acids having five to ten carbon atoms, or a branched chain acid having from five to eighteen carbon atoms preferably five to nine carbon atoms, namely 2-methylhexanoic, 2-ethylpentanoic, 3,5,- trimethylhexanoic acids or mixtures thereof.
  • the acids are monocarboxylic acids.
  • Suitable straight chain acids include, but are not limited to, valeric acid (C 5 ), oenanthic acid (C 7 ), caprylic acid CC 8 ), pelargonic acid (C9), and capric acid (C10).
  • the acid mixture is pres-..; in an excess of about 10 to 50 mole percent more than the stoichiometric equivalent of the hydroxyl group on the polyol used.
  • the excess acid is used to force the reaction to completion.
  • the composition of the feed acid is adjusted so as to provide the desired composition of product ester. After the reaction is complete, the excess acid is removed by stripping and additional finishing.
  • This process utilizes an optical cell or any other suitable fiber optical probe to illuminate the esterification stream with optical radiation, determining the differences in the optical abso ⁇ tivity of the stre: * at predetermined wavelengths, and for determining the conversions ar ⁇ or concentrations of water, acids, and or polyol, and/or other compositional properties of the esterification reaction mixture, polyol ester product stream and enriched polyol ester product stream from the difference in the optical abso ⁇ tivity.
  • abso ⁇ tivity as the negative of the logarithm of the ratio of the transmitted light intensity to the incident light intensity, the logarithm being divided by the path- length through the absorbing material by the light. The absorbance is the abso ⁇ tivity multiplied by the path-length.
  • the near and mid-infrared analyzers comprise hardware and software to determine the abso ⁇ tivity of the process stream over a range of wavelengths in the near or mid-infrared, respectively, followed by analysis of the spectrum by means of a multivariate statistical calibration model, the output of which provides predictions of the physical and/or chemical properties and composition of the process stream.
  • the analyzer is sufficiently accurate, precise, reliable, and rapid to be suitable for providing process control information.
  • the use of fiber optics make remote application of near and mid- infrared analyzers possible in varying process conditions and in hostile environments.
  • Multivariate analysis of near infrared spectra is usually necessary to extract chemical or physical information since there is often significant overlap between the spectra of different compounds in the near and mid-infrared range.
  • the model provides statistically accurate predictions even under varying conditions, such as temperature.
  • PLS partial least squares
  • UnscramblerTM software sold by Guided Wave, Inc.
  • the partial least squares scheme is a multivariate solution for distinguishing broad and overlapping absorbance bands in a near infrared spectroscopy.
  • This software generates a statistical model that can relate some measurable quantity (i.e., spectrum, chromatogram, sensory data) to an unknown quantity (i.e., factors).
  • Additional sample and alternative modeling techniques may improve prediction capability of the near or mid-infrared analyzer beyond that demonstrated in the examples to follow.
  • a typical esterification synthesis syste is set forth in fig. 9, wherein a polyol limiting reagent is mixed with at least one acid within reaction vessel 1.
  • the esterification reaction within vessel 1 occurs in the presence of a catalyst.
  • Acid and water vapors are taken overhead via conduit 3 and acid is returned to vessel 1 after condensation and separation from the water.
  • reaction conversion of polyol to the polyol ester, the polyol concentration and the water concentration of vessel 1 contents can be measured by infrared analyzer 56.
  • a polyol ester product solution is taken as bottoms via conduit 5 and delivered to reaction vessel 7 wherein the polyol ester product solution is treated either simultaneously or sequentially as follows:
  • the bottoms are passed via conduit 11 through filter unit 17 to remove solids (i.e., hydrolyzed catalyst, absorbent, filter aids, carbon, etc.) and thereafter passed on to stripping tower or reactor 21.
  • solids i.e., hydrolyzed catalyst, absorbent, filter aids, carbon, etc.
  • reaction vessel 7 can be used as a stripping vessel. Steam or nitrogen is introduced via conduit 10 and the remaining acid and water is removed with the application of heat and vacuum. When vessel 7 is also used as a stripping vessel, the water concentration and acid concentration can be monitored by near or mid-infrared analysis. Following step (e), the bottoms are filtered through filter 17 to remove solids.
  • the properties of the contents in vessel 7, the concentration of the polyol ester product, the acid concentration, and the water content can be monitored by means of near or mid-infrared analyzer 56.
  • the measurement of the water content is particularly important in determining the ease of filtration in filter 17.
  • the water concentration in conduit 11 should be less than 1000 ppm and preferably below 500 ppm.
  • the solids are taken as bottoms via conduit 19 and the filtered polyol ester product is sent to stripping tower 21 through heater 30 via conduit 23. In stripping tower 21, excess acid is removed from the polyol ester product by steam or nitrogen stripping under partial vacuum and recycled to successive batches in reaction vessel 1 via conduit 20.
  • the polyol ester enriched-product is taken as bottoms from tower 21 via conduit 25 and delivered to a second filter 27 wherein solids are taken out as bottoms via conduit 29 and further enriched polyol ester product is sent via conduit 26 to run-down tank 32.
  • the residual water content, the residual polyol content, and the residual acid content may be measured in the final stripped polyol ester product using near infrared analyzer 56 on-line in conduit 25.
  • an in-line near or mid-infrared analyzer 56 is in fluid contact with reaction vessel 1 via conduit 54.
  • Analyzer 56 comprises a means for generating a near or mid-infrared spectra of the reaction mixture and a means for applying a mathematical model and the spectrum data, that model embodying the relationship between the near or mid- infrared spectra and the properties or chemical compositions to e predicted.
  • the measured near or mid-infrared spectral data is processed by a computer 58 (CPU) which contains a calibration or multivariate model (e.g., multiple linear regression, principal components regression, partial least squares, or neural net); whereby an accurate prediction of either the conversions and/or 16
  • CPU computer 58
  • a calibration or multivariate model e.g., multiple linear regression, principal components regression, partial least squares, or neural net
  • Typical on-line near or mid- infrared analyzer 56 includes a pump 52, heat exchanger 50, and thermometer 51.
  • the resultant predictions are sent to CPU 58 where they are processed and if the predicted property/composition value meets a predetermined target value, then the results are recorded and the process stream is analyzed again. If, however, the predicted value is less than or greater than the target value, then a signal is sent to the process control system instructing it to adjust the reaction conditions and/or concentrations of acids and/or polyols depending upon the degree of conversions and/or concentrations predicted by analyzer 56.
  • reaction vessel 7 In the case of reaction vessel 7, or other configurations where solids are present, a small filter will be placed in conduit 54 just after pump 52 and before heat exchanger 50 to remove solids from the stream which is fed to infrared analyzer 56.
  • Near or mid-infrared analyzers may also be used to detect concentration and conversion properties in other parts of the esterification process, e.g., finishing vessel 7 (e.g., a flashing vessel), stripper reactor 21, and run-down tank 32.
  • finishing vessel 7 e.g., a flashing vessel
  • stripper reactor 21 e.g., a flashing vessel
  • run-down tank 32 e.g., a flashing vessel
  • the near infrared analyzer associated with stripper reactor 21 is preferably disposed about conduit 25 which is downstream of the bottoms discharged from stripper reactor 21.
  • the esterification process may be configured in several ways to meet individual processor requirements.
  • the near infrared analyzer 56 is adapted by easily engineered sampling techniques to measure reaction conversion and the concentrations of acids and water in any of several typical process configurations.
  • One example offlexibility was demonstrated above with the optional step (e).
  • the infrared analysis technique can be readily adapted to a completely continuous process for all steps or for a process where all the steps take place consecutively in a single reactor.
  • the infrared analysis technique is particularly well suited for monitoring any process ,J in real-time for more efficient utilization of the equipment tin the particular esterification process.
  • the acid is recycled to the next batch; whereas during a continuous process the acid is recycled to the esterification reaction vessel.
  • the esterification, stripping and run-down processes 70 are continuously monitored by means of near or mid-infrared analyzer(s) 72 to determine the abso ⁇ tivity of the process stream over a range of wavelengths in the near or mid-infrared spectrum.
  • the spectral data from analyzer 72 is thereafter sent to a microprocessor where the data is pre-processed 74, and analyzed by a multivariate statistical calibration model 76.
  • Pre-processing may include determining the quality of the spectrum, correcting the spectrum for instrumental distortions, differentiating the spectrum one or more times, and taking the Forier transform of the spectrum.
  • Model 76 may include any known mathematical modeling technique which is capable of providing accurate i iictions 78 of the physical or chemical properties and composition of the process stream, e.g., multiple linear regression models, principal component regression models, partial least squares models, or neural net models. Thereafter, the predicted property/composition of the process stream is compared against predetermined property/composition values 80. If the predicted values meet the predetermined values the results are recorded 82 and a signal is sent to repeat the infrared analysis 72. If the predicted values to not meet the predetermined values, then process control system 84 either increases or decreases the concentration of the respective reactants in process 70.
  • the present inventors have discovered that near infrared pH stretching spectra can readily distinguish water hydroxyl groups from polyol hydroxyl group transitions. Near infrared analysis allows one to evaluate water concentration in the presence of carboxylic acid and polyols.
  • TMP trimethylol propane
  • the first set was comprised of five samples: pure heptanoic acid (C 7 acid) and four mixtures of TMP, C acid, and water.
  • the component concentration of these five samples, as prepared gravimetrically are shown below in Table 2.
  • the measurement objective of this experiment was to determine whether the hydroxyl groups of the acid, polyol and water in mixtures can be distinguished by their near infrared spectra, and also how well the TMP content could be estimated on the basis of these spectra.
  • the second sample set comprised four reaction mixtures containing fully-converted tri-esters (TE), partially-converted di-esters (DE), excess carboxylic acids (C ⁇ , C , C 8 , and Cio), and water. These compositions were determined using gas chromatography and Karl Fischer titration (for the water). The component concentrations and TMP conversion are given below in Table 3. The objective of these measurements was to estimate the conversion of the TMP to the tri-ester.
  • the near infrared absorbance spectra of the TMP/C 7 acid mixtures comprising the first sample set are shown in Fig. 1.
  • the 1200 nm peak shows little visually discernible variation between the samples. This band is predominantly due to the second overtone of the unresolved vibrational stretching modes of the CH groups.
  • the 1420 nm band is dominated by the first overtone of the OH vibrational stretching modes of the alcohol (polyol), acid, and water. Combination bands of the first overtone of the CH stretch and fundamental CH bending modes also contribute in this wavelength region. Clearly, the spectral information relevant to the compositional variation of the samples is contained in the 1300-1600 nm wavelength region, consistent with the OH abso ⁇ tion bands.
  • the absorbances at just two wavelengths are sued.
  • the absorbance at one of the wavelengths may be chosen as a reference to compensate for instrumental drifts and other effects not related to the TMP, while the absorbance at the second wavelength provides information on the TMP content.
  • a suitable reference wavelength may be chosen at 1300 nm.
  • the different spectra, A(x nm) minus A(1300 nm), where x takes the value of each wavelength between 1300 nm and 1600 nm, are shown in fig. 2. It can be seen that there is no obvious best choice of an analytical wavelength for the TMP content.
  • Fig. 3 shows the standard errors of estimate (SEE) for estimating the wt.% of TMP in the mixtures as a function of the wavelength.
  • SEE standard errors of estimate
  • the best SEE was 0.044 wt.% using the absorbance difference at 1437 nm and 1300 nm.
  • good estimates of the TMP content could be obtained by using the absorbance at any wavelength between about 1420 nm and 1540 nm as an analytical wavelength.
  • the absorbance at 1437 nm, referenced to the heptanoic acid, and the TMP content of the samples is shown in Table 5 below. A linear-dependence of absorbance with TMP may be seen, indicating Beer's Law behavior and the absence of discernible hydrogen-bonding at these concentration levels.
  • Mid-IR abso ⁇ tion spectra also show good correlation to both the TMP and water contents of these mixtures.
  • the standard errors of estimate for PLS models based on spectra in selected wavelength regions show better estimation of the TMP and water than obtained in the near infrared by factors of 10 and 3, respectively.
  • the present inventors have discovered that both near and mid-IR spectroscopy, coupled with multivariate modeling can be used to estimate the polyol and water content of mixtures in the presence of excess heptanoic acid. Using near infrared data, standard errors of 0.04 wt.% TMP and 21 ppm H 2 O were obtained.
  • PC Principal component
  • SUBSTTTUTE SHEET (RULE 26) wavelengths between 1300 nm and 1600 nm in each absorbance spectrum) to about 4, at most, is obtained by the PC transformation.
  • the "leave-one-out” cross-validation procedure involves leaving the spectrum and properties of one of the samples out of the data set, using the principal component analysis to obtain the best model to estimate the properties of the remaining samples, and then to use this model to predict the properties of the excluded sample.
  • the standard deviation of the residuals between the predicted and actual values was calculated. This quantity is used as a measure of how well the composition and conversion can be predicted, and which of the PC variables should be included in the model.
  • the final step is to use the "best" predictive model, as determined by the PRESS statistic, to estimate the properties of the entire data set in order to obtain the conventional standard error of estimate.
  • Fig. 8 shows the spectra of the di- and tri-esters and the acid.
  • the acid in these samples is a mixture
  • This example compares actual compositional variables versus the use of in-line/on-line near infrared to predict compositional variables in the process of esterification of pentaerythritol (PE) in the presence of excess carboxylic acids.
  • the models based upon near-IR and mid-IR absorbance spectra, can be used to predict the hydroxyl conversion to about 0.02%, and the di-ester and tri-ester and water contents to 0.04, 0.5, and 0.002 wt.%, respectively.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Investigating Or Analysing Materials By Optical Means (AREA)
  • Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)

Abstract

On surveille un mélange de réaction d'estérification composé d'un acide et d'un polyol par une analyse effectuée dans l'infrarouge proche ou moyen, de façon à prévoir des conversions et/ou des concentrations en eau, en acides et/ou polyol, et/ou d'autres propriétés tenant aux compositions du mélange de réaction mis en présence d'acide carboxylique excédentaire, ce qui permet de commander en temps réel l'ensemble du processus d'estérification.
PCT/US1995/013108 1994-09-28 1995-09-28 Procede de commande, par l'analyse dans l'infrarouge proche ou moyen, de la conversion d'un ester de polyol Ceased WO1996010009A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU38311/95A AU3831195A (en) 1994-09-28 1995-09-28 A method for controlling polyol ester conversion using near or mid-infrared analysis

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US31447694A 1994-09-28 1994-09-28
US08/314,476 1994-09-28

Publications (1)

Publication Number Publication Date
WO1996010009A1 true WO1996010009A1 (fr) 1996-04-04

Family

ID=23220106

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US1995/013108 Ceased WO1996010009A1 (fr) 1994-09-28 1995-09-28 Procede de commande, par l'analyse dans l'infrarouge proche ou moyen, de la conversion d'un ester de polyol

Country Status (2)

Country Link
AU (1) AU3831195A (fr)
WO (1) WO1996010009A1 (fr)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2000040950A1 (fr) * 1999-01-05 2000-07-13 Astrazeneca Ab Suivi de reactions
WO2001002088A1 (fr) * 1999-07-06 2001-01-11 Neste Chemicals Oy Procede de commande du processus de fabrication des polyols
WO2001021302A1 (fr) * 1999-09-20 2001-03-29 General Electric Company Procede et dispositif permettant de conduire des reactions de polymerisation-fusion
WO2002000760A1 (fr) * 2000-06-23 2002-01-03 General Electric Company Evaluation par infrarouge du rapport stoechiometrique du phenol dihydrique sur le diarylcarbonate durant le production de polycarbonates
EP1512960A1 (fr) * 2003-08-11 2005-03-09 Bayer Chemicals AG Détermination spectroscopique de concentration dans une colonne de rectification
WO2006136230A1 (fr) * 2005-06-24 2006-12-28 Hexion Specialty Chemicals Research Belgium S.A. Procede d'esterification de polyols a partir d'acides substitues par des groupes alkyles tertiaires
CN111595807A (zh) * 2020-07-03 2020-08-28 南京农业大学 一种生物基食品包装膜中己内酰胺的定量检测方法

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH02306936A (ja) * 1989-05-22 1990-12-20 Kao Corp 自動エステル化方法
JPH02306937A (ja) * 1989-05-22 1990-12-20 Kao Corp 自動ポリエステル化方法

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH02306936A (ja) * 1989-05-22 1990-12-20 Kao Corp 自動エステル化方法
JPH02306937A (ja) * 1989-05-22 1990-12-20 Kao Corp 自動ポリエステル化方法

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
PATENT ABSTRACTS OF JAPAN vol. 15, no. 92 (C - 0811) 6 March 1991 (1991-03-06) *
PATENT ABSTRACTS OF JAPAN vol. 19, no. 92 (C - 0811) 6 March 1991 (1991-03-06) *

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2000040950A1 (fr) * 1999-01-05 2000-07-13 Astrazeneca Ab Suivi de reactions
WO2001002088A1 (fr) * 1999-07-06 2001-01-11 Neste Chemicals Oy Procede de commande du processus de fabrication des polyols
WO2001021302A1 (fr) * 1999-09-20 2001-03-29 General Electric Company Procede et dispositif permettant de conduire des reactions de polymerisation-fusion
WO2002000760A1 (fr) * 2000-06-23 2002-01-03 General Electric Company Evaluation par infrarouge du rapport stoechiometrique du phenol dihydrique sur le diarylcarbonate durant le production de polycarbonates
US6437082B1 (en) 2000-06-23 2002-08-20 General Electric Company Infrared evaluation of the stoichiometric ratio of dihydric phenol to diarylcarbonate during production of polycarbonates
EP1512960A1 (fr) * 2003-08-11 2005-03-09 Bayer Chemicals AG Détermination spectroscopique de concentration dans une colonne de rectification
WO2006136230A1 (fr) * 2005-06-24 2006-12-28 Hexion Specialty Chemicals Research Belgium S.A. Procede d'esterification de polyols a partir d'acides substitues par des groupes alkyles tertiaires
US7737297B2 (en) 2005-06-24 2010-06-15 Hexion Specialty Chemicals, Inc. Esterification process of polyols with tertiary alkyl substituted acids
US7960493B2 (en) 2005-06-24 2011-06-14 Momentive Specialty Chemicals Inc. Esterification process of polyols with tertiary alkyl substituted acids
CN111595807A (zh) * 2020-07-03 2020-08-28 南京农业大学 一种生物基食品包装膜中己内酰胺的定量检测方法
CN111595807B (zh) * 2020-07-03 2022-05-06 南京农业大学 一种生物基食品包装膜中己内酰胺的定量检测方法

Also Published As

Publication number Publication date
AU3831195A (en) 1996-04-19

Similar Documents

Publication Publication Date Title
US7404411B2 (en) Method and apparatus for analysis of relative levels of biodiesel in fuels by near-infrared spectroscopy
US6552221B1 (en) Process control for acetic acid manufacture
US5596196A (en) Oxygenate analysis and control by Raman spectroscopy
Moh et al. Determination of peroxide value in thermally oxidized crude palm oil by near infrared spectroscopy
Pereira et al. NIR spectrometric determination of quality parameters in vegetable oils using iPLS and variable selection
EP2131181B1 (fr) Procédé pour la détermination du nombre total d'acide et nombre d'acide naphténique de pétrole, coupes de pétrole et émulsions de pétrole de type eau dans l'huile par une spectroscopie à infrarouge moyen
CA1333447C (fr) Methode de determination directe des proprietes physiques de produits d'hydrocarbones
CA2064833C (fr) Procede amelioree de determination de l'indice d'octane et dispositif connexe
Cunha et al. Predicting the properties of biodiesel and its blends using mid-FT-IR spectroscopy and first-order multivariate calibration
EP2321631B1 (fr) Système et procédé d'analyse d'un processus d'alkylation
RU2001126054A (ru) Способы оптимального использования и усовершенствованной оценки коррозионного нефтяного сырья и фракций
WO1996010009A1 (fr) Procede de commande, par l'analyse dans l'infrarouge proche ou moyen, de la conversion d'un ester de polyol
WO2011112281A1 (fr) Système et procédé d'analyse d'un processus d'alkylation
Zhou et al. A rapid determination of wheat flours components based on near infrared spectroscopy and chemometrics
RU2585614C2 (ru) Способ получения винилацетата
WO1999041591A1 (fr) Regulation de la teneur en eau d'un procede de reformage catalytique servant a produire des composants de melange d'essence, au moyen d'une spectroscopie dans l'infrarouge proche
WO1995033705A1 (fr) Procede pour controler la conversion de plastifiants au moyen de l'analyse dans l'infrarouge proche
Heikka et al. Determination of acid value, hydroxyl value and water content in reactions between dicarboxylic acids and diols using near-infrared spectroscopy and non-linear partial least squares regression
Helminen et al. Monitoring the kinetics of the ion-exchange resin catalysed esterification of acetic acid with ethanol using near infrared spectroscopy with partial least squares (PLS) model
Baeten et al. Olive oil analysis by infrared and Raman spectroscopy: methodologies and applications
Blanco et al. Study of reaction processes by in-line near-infrared spectroscopy in combination with multivariate curve resolution: esterification of myristic acid with isopropanol
JP3549238B2 (ja) 赤外吸収スペクトルに基づく酸価、ヒドロキシル価およびエステル価の同時測定法
Pelletier et al. On-line analysis of a continuous-flow ozonolysis reaction using Raman spectroscopy
WO2001002088A1 (fr) Procede de commande du processus de fabrication des polyols
Bartl et al. An interlaboratory comparison of sample presentation methods for the analysis of aqueous solutions using fourier transform infrared spectroscopy

Legal Events

Date Code Title Description
AK Designated states

Kind code of ref document: A1

Designated state(s): AU BR CA CN JP KR MX RU SG

AL Designated countries for regional patents

Kind code of ref document: A1

Designated state(s): AT BE CH DE DK ES FR GB GR IE IT LU MC NL PT SE

DFPE Request for preliminary examination filed prior to expiration of 19th month from priority date (pct application filed before 20040101)
121 Ep: the epo has been informed by wipo that ep was designated in this application
122 Ep: pct application non-entry in european phase
NENP Non-entry into the national phase

Ref country code: CA