Acrylic acid distillation

The residue is then placed in a modified Claisen flask (Org. Syn. 22, 11) and distilled under reduced pressure. Dimethyl-acrylic acid distils at 100-106°/20 mm. The yield of white solid is 49-53 g. (49-53 per cent of the theoretical amount). This product melts at 60-65°. It may be further purified by recrystallization from petroleum ether (b.p., 60-70°) or water (Note 5). 

For accurate and reproducible polymerization studies involving acrylic acid, distillation of the monomer is mandatory. Unlike methacrylic acid, acrylic acid dimerizes spontaneously around 30°C at a rate of 1.0-1.5% per month [Eq. (1)] [1]. 

There are several possible causes for the off-specification acrylic acid product. The most likely causes are changes that may have occurred during shutdown. Perhaps the new catalyst is not performing as designed. Perhaps the new solvent is contaminating the product. The reactor effluent and the extractor effluent streams should be checked for contamination. Suppose that has been done, and everything has been found to be within normal conditions. Therefore, the most likely cause involves the tenperature in the acrylic acid distillation column. In this column, acrylic acid and acetic acid are separated. It will be assumed that this is a simple binary distillation. 

CHi=CMeCOOH. Colourless prisms m.p. 15-16 C, b.p. 160-5 C. Manufactured by treating propanone cyanohydrin with dilute sulphuric acid. Polymerizes when distilled or when heated with hydrochloric acid under pressure, see acrylic acid polymers. Used in the preparation of synthetic acrylate resins the methyl and ethyl esters form important glass-like polymers. 

Transition metal oxides or their combinations with metal oxides from the lower row 5 a elements were found to be effective catalysts for the oxidation of propene to acrolein. Examples of commercially used catalysts are supported CuO (used in the Shell process) and Bi203/Mo03 (used in the Sohio process). In both processes, the reaction is carried out at temperature and pressure ranges of 300-360°C and 1-2 atmospheres. In the Sohio process, a mixture of propylene, air, and steam is introduced to the reactor. The hot effluent is quenched to cool the product mixture and to remove the gases. Acrylic acid, a by-product from the oxidation reaction, is separated in a stripping tower where the acrolein-acetaldehyde mixture enters as an overhead stream. Acrolein is then separated from acetaldehyde in a solvent extraction tower. Finally, acrolein is distilled and the solvent recycled. 

Acrylic acid (AA) and methacrylic acid (MAA) (purchased from Merck) are freed from inhibitor on a neutral aluminium oxid column and distilled. Acrylamide (AM) from Kebo, Stockholm, is recrystallized once from chloroform solution before use. Other monomers of analytical grade were purchased from Merck and used as received crotonic acid (CA), tiglic acid (TA), 3-methyl crotonic acid (3-MCA), and a-methyl cinnamic acid (oi-MCia) (Table 1). Benzophenone (analytical grade, Kebo) and acetone (spectroscope grade, Merck) were used as supplied. 

The preparation of fluorinated alcohols was carried out in multistep routes according to the reported procedures.1012 The synthesis of acrylic and methacrylic esters as shown in Table 11.1 was carried out in a fluorocarbon solvent such as Freon 113 by the reaction of the respective fluorinated alcohol with acryloyl chloride or methacryloyl chloride and an amine acid acceptor such as triethyla-mine with examples shown in Scheme 1. Other attempts to esterify the fluoroalcohols directly with acrylic acid or acrylic anhydride were not successful.11 Product purification by distillation was not feasible because of the temperature required, but purification by percolation of fluorocarbon solutions through neutral alumina resulted in products of good purity identified by TLC, FTIR, and H-, 13C-, and 19F- FTNMRs. 

Dimethylacetamide (DMAc), cellulose solvent (with lithium chloride), 5 384 N, N-Dimethylacetamide (DMAc), 23 703 extractive distillation solvent, 8 802 solvent for cotton, 8 21 N, AA-Dimethylacrylamide (DMA), 20 487 P,P-Dimethyl acrylic acid, physical properties, 5 35t Dimethylallylamine, 2 247... 

The experimental procedures were essentially the same as reported (Figure 1, (16, 17)). Reagents other than those described in (16. 17) were as follows. Acrylic acid(Wako Pure Chemicals) was distilled once under reduced pressure under a nitrogen stream. Solvents(acetonitrile, n-hexane, and benzene) were purified by accepted procedures. 

The concentration of acrylic acid by extraction with ethyl acetate is a rather different illustration of this technique. As shown in Figure 13.4, the dilute acrylic acid solution of concentration about 20 per cent is fed to the top of the extraction column 1, the ethyl acetate solvent being fed in at the base. The acetate containing the dissolved acrylic acid and water leaves from the top and is fed to the distillation column 2, where the acetate is removed as an azeotrope with water and the dry acrylic acid is recovered as product from the bottom. 

British Patent No. 995472 Distillers Company Limited (29 April 1964). Acrylic acid recovery. 

The conventional techniques for the purification of low-molecular-weight compounds, such as distillation, sublimation, and crystallization, are not applicable to polymers. In some cases, it is possible to remove the impurities by cold or hot extraction of the finely powdered polymer with suitable solvents or by steam distillation. Separation of low-molecular-weight components from water-soluble polymers [e.g., poly(acrylic acid),poly(vinyl alcohol), poly(acryl amide)]... 

Fury[- acrylic Acid (Furfuralacetic Acid or Furacetic Acid), O.CH CH.CH C.CH CH.CQ0H mw 138.12. Exists as stable and labile isomers. The stable form. ndls(w), rap 141° bp (with quick heating) 255—65°(286°) sol in ale, eth, benz, HAc hot w steam distils. Can be prepd by refluxing furfural with NaAc (Refs 1, 2 4). The labile form prisms plates (benz), mp 103—04° sol in benz hot w. Was prepd by refluxing furfuridine malonic acid with Ac30 and cecrystn as its piperidine salt from benz (the salt of the stable form is more sol in benz (Ref 3)... 

PMA homopolymer is also available as a neutralized salt and in several grades, often with precise molecular weight distributions, for special applications such as antiscalent duty in seawater distillation and sugar evaporator processes. Maleic anhydride chemistry has also been successfully developed to provide functional components in copolymers [examples are acrylic acid, maleic anhydride (AA/MA) and sulfonated styrene, maleic anhydride (SS/MA)] and terpolymers [example is maleic anhydride, ethyl acrylate, vinyl acrylate (MA/EA/VA)]. 

After this the mixture is acidified with hydrochloric acid and the acrylic acid separated by distillation with steam. 

The acrylic acid used in this study was normally distilled once prior to each use. However, in an attempt to increase grafting yields, the effect of redistilling was examined. Somewhat higher yields were obtained with the redistilled acrylic acid. For example, 47.5% grafting was obtained by redistilling as opposed to 39.2% for single distillation. Further distillations were not performed due to the susceptibility of uninhibited acrylic acid to spontaneous polymerization. The effect of monomer purity will be examined more extensively in future work. 

Polypropylene (PP) foils with a thickness of 100 pm (goodfellow, U.K.) or 300 im (Ciba Geigy Switzerland) as well as polyethylene (PE, Lupolen, BASF) foil (100 pm) were ultrasonically cleaned in a diethyl ether bath for 15 min. The monomers used, i.e. acrylic acid, allyl alcohol and allylamine (all > 99%), were purchased from Merck KGaA, Darmstadt, Germany and distilled before use. The monomers, ethylene and butadiene-1,3, supplied by Messer-Griesheim GmbH, Germany, were used as received. 

To fit these to-hydroxy telomers with terminal double bonds they were esterified with acrylic acid in the presence of p-toluenesulfonic acid. Subsequent azeotropic distillation of the formed water yields macromonomers exhibiting the following structure... 

Methyl methacrylate (MMA), ethyl methacrylate (EMA), n-butyl methacrylate (n-BMA), styrene (Sty), acrylonitrile (AN), vinyl acetate (VA), methyl acrylate (MA), isoprene (IP), and isobutyl vinyl ether (IBVE) were all dried over anhydrous barium oxide and distilled at or below 25°C. (except n-BMA, 35°-40°C.) under low nitrogen pressure. Acrylic acid (AA) was dried over anhydrous sodium sulfate and distilled under vacuum before use. 

Acrylic acid (of Compagnie Nobel-Bozel or Uglior) was used without further purification. 4-Vinylpyridine (Fluka) was distilled twice under vacuum (b.p., = 58°C. at 12 mm. Hg) and stored in a refrigerator under nitrogen. Small pieces of PTFE, 10 X 20 to 10 X 40 mm.2 were cut from commercial films 0.1- and 0.05-mm. thick. They were immersed for 24 hours in either chromic acid or methanol at room temperature, washed, and dried under vacuum. 

B. Ethyl a-(bromomethyl)acry late. In a nitrogen-flushed, 1-L, round-bottomed flask equipped with a magnetic stirrer, Dean-Stark trap, and condenser are placed 42.0 g (0.25 mol) of a-(bromomethyl)acrylic acid and 300 mL of benzene. Approximately 50 mL of a binary azeotrope of benzene and water is distilled (Note 7). The Dean-Stark trap is removed and 100 mL of absolute ethanol (Note 8) and 1 mL of concentrated sulfuric acid are added slowly. The contents of the flask are boiled in a nitrogen atmosphere for 36 hr, the condensate being passed through 100 g of molecular sieves (Linde 3A) before being returned to the flask. About 125 mL of a mixture of benzene and ethanol is removed from the reaction... 

The Step 1 product (1427 parts) was converted into the corresponding acrylate ester by treating with acrylic acid (216 parts), sulfuric acid (5 parts) in methyl-cyclohexane (345 parts), hydroquinone monomethyl ether (3 parts), triphenyl phosphite (1 part), and hypophosphorous acid (1 part). The reaction continued until 44 parts of water were removed before beginning the vacuum distillation. The residue was purified by filtering through a K300 filter, and the acid number was determined. The product viscosity was adjusted to 330 mPas by the addition of 96 parts of acrylic acid, and a colorless product was isolated. 

Tlie extract is vacuum-distilled in the solvent recovery column, which is operated at low bottom temperatures to minimize the formation of polymer and dimer and is designed to provide acrylic acid-free overheads for recycle as the extraction solvent. A small aqueous phase in the overheads is mixed with the raffinate from the extraction step. Tliis aqueous material is stripped before disposal both to recover extraction solvent values and minimize waste organic disposal loads. 

Acrylic acid, alcohol, and the catalyst, eg, sulfuric acid, together with the recycle streams are fed to the glass-lined ester reactor fitted with an external reboiler and a distillation column. Acrylate ester, excess alcohol, and water of esterification are taken overhead from the distillation column. The process is operated to give only traces of acrylic acid in the distillate. The bulk of the organic distillate is sent to the wash column for removal of alcohol and acrylic acid a portion is returned to the top of the distillation column. If required, some base may be added during the washing operation to remove traces of... 

Reppe s work also resulted in the high pressure route which was established by BASF at Ludwigshafen in 1956. In dais process, acetylene, carbon monoxide, water, and a nickel catalyst react at about 200°C and 13.9 MPa (2016 psi) to give acrylic acid. Safety problems caused by handling of acetylene are alleviated by the use of tetrahydrofuran as an inert solvent. In this process, the catalyst is a mixture of nickel bromide with a cupric bromide promotor. The liquid reactor effluent is degassed and extracted. The acrylic acid is obtained by distillation of the extract and subsequendy esterified to the desired acrylic ester. The BASF process gives acrylic acid, whereas the Rohm and Haas process provides the esters direcdy. 

Tire sulfuric acid hydrolysis may be performed as a batch or continuous operation. Acryloioitrile is converted to acrylamide sulfate by treatment with a small excess of 85% sulfuric acid at 80—100°C. A hold-time of about 1 h provides complete conversion of the acrylonitrile. The reaction mixture may be hydrolyzed and the aqueous acrylic acid recovered by extraction and purified as described under the propylene oxidation process prior to esterification. Alternatively, after reaction with excess alcohol, a mixture of acrylic ester and alcohol is distilled and excess alcohol is recovered lay aqueous extractive distillation. The ester in both cases is purified by distillation. 

Historically, the development of the acrylates proceeded slowly they first received seiious attention from Otto Rohm. Acrylic acid (propenoic acid) was first prepared by the ah oxidation of acrolein in 1843 (1,2). Methyl and ethyl acrylate were prepared in 1873, but were not observed to polymerize at that time (3). In 1880 poly(metliyl acrylate) was reported by G. W. A. Kahlbaum, who noted that on dry distillation up to 320°C the polymer did not depolymerize (4). Rohm observed the remarkable properties of acrylic polymers while preparing for his doctoral dissertation in 1901 however, a quarter of a century elapsed before he was able to translate his observations into commercial reality. He obtained a U.S. patent on the sulfur vulcanization of acrylates in 1912 (5). Based on the continuing work in Robin s laboratory, the first limited production of acrylates began in 1927 by the Rohm and Haas Company in Darmstadt, Germany (6). Use of this class of compounds has grown from that time to a total U.S. consumption in 1989 of approximately 400,000 metric tons. Total worldwide consumption is probably twice that. 

A mixture of 1 kg. (18.9 moles) of acrylonitrile Caution—volatile toxic material), 6 g. of hydroquinone, 14 g. of copper powder, 648 g. of ice, and 1012 ml. of concentrated sulfuric acid is heated gradually under a reflux condenser on a steam bath. The exothermic reaction is controlled by cautious application of heat, particularly during the first hour. Heating is continued for 48 hours, after which the mixture is cooled and the precipitated ammonium bisulfate is filtered off. The crude acid is distilled by dropping it into a distilling flask loosely packed with fine copper wire and heated to a bath temperature of 250°. The system is maintained under a pressure of about 10 mm, and the distillation receiver is packed in ice. Approximately 1 kg. of clear, colorless distillate is obtained which is shown by analysis to be 86% acrylic acid free of sulfur and nitrogen. 

A mixture of 216 g. (3.0 moles) of acrylic acid (p. 3), 844 g. (6.0 moles) of benzoyl chloride, and 0.5 g. of hydroquinone is heated under an efficient fractionating column. The distillation receiver contains 0.5 g. of hydroquinone and is immersed in an ice bath. The reaction mixture is distilled rather rapidly, and the distillate boiling up to 85° is collected (most boils in the range 60-70°). The distillate (215-225 g.) is redistilled through the same column, and the... 

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