Acrylic acid producers

ACROLEIN AND DERIVATIVES. Acrolein (2-propenal), C3H4O, is the simplest unsaturated aldehyde (CH2=CHCHO). The primary characteristic of acrolein is its high reactivity due to conjugation of the carbonyl group with a vinyl group. More than 80% of the refined acrolein that is produced today goes into the synthesis of methionine. Much larger quantities of crude acrolein are produced as an intermediate in the production of acrylic acid. More than 85% of the acrylic acid produced worldwide is by the captive oxidation of acrolein. 

In the two-step process, the second-stage reactor is similar to the first-stage reactor but is packed with an optimized catalyst for aldehyde oxidation, based on Mo V oxides, and is run under different operating conditions. Care must be exercised during the separation and purification phases to avoid conditions favouring acrylic acid polymerization, e.g., by addition of a radical polymerization inhibitor such as the hydroquinone monomethyl ether. Selectivities to acrylic acid are higher than 90% at total conversion of the aldehyde. Overall yields referred to propylene are in the range 75-85%. Most acrylic acid produced is esterified for the production of acrylate esters. 

Virtually all of the acrylic acid produced in the United States is made by the oxidation of propylene via the intermediacy of acrolein. 

Acrylic acid produces an alternating copolymer with 1,3,3-trimethyl azetidine below 80° C, but long acrylic acid sequences above this temperature, since, under these reaction conditions, acrylic acid homopolymerizes already at 150°C to poly(i8-propiolactone) with the monomeric unit - -O—CHz — CH2 —CO But the joint polymerization of 1,3,3-trimethyl azetidine with... 

Studies have been carried out using combinations of acrylic acid and isostearic acid in an attempt to produce surface modifier systems that combine effective coupling with good dispersant characterisics [13]. In this study sequential adsorption of isostearic acid and acrylic acid on to magnesium and aluminium hydroxides in the FMC cell indicated that acrylic acid will displace isostearic acid from both fillers, however, isostearic acid will adsorb onto a layer of adsorbed acrylic acid producing a hybrid layer. 

Silica surface was treated with APS and modified with poly(acrylic acid), using the reaction illustrated in Scheme 1. The carboxyl groups on poly(acrylic acid) reacted with the APS amine functional groups to form salt bonds on the surface of silica. The salt-modified beads were heated in DMF at 140°C to form amide bonds. The FTIR spectrum of the APS-modified silica exhibited a peak at about 1600 cm due to the amino group in addition to the original silica peak. Treatment with poly(acrylic acid) produced new peaks at 1710 cm" and 1660 cm", indicating the carboxyl groups of poly(acrylic acid) and the amide bond formation between the poly(acrylic acid) and the bound APS, respectively. ... 

Polylacrylic Acid) and Poly(methacrylic Acid). Glacial acrylic acid and glacial meth-acrylic acid can be polymerized to produce water-soluble polymers having the following structures ... 

The significance of industrial acrolein production may be clearer if one considers the two major uses of acrolein—direct oxidation to acryUc acid and reaction to produce methionine via 3-methyhnercaptopropionaldehyde. In acryUc acid production, acrolein is not isolated from the intermediate production stream. The 1990 acryUc acid production demand in the United States alone accounted for more than 450,000 t/yr (28), with worldwide capacity approaching 1,470,000 t/yr (29). Approximately 0.75 kg of acrolein is required to produce one kilogram of acryUc acid. The methionine production process involves the reaction of acrolein with methyl mercaptan. Worldwide methionine production was estimated at about 170,000 t/yr in 1990 (30). (See Acrylic ACID AND DERIVATIVES AmINO ACIDS, SURVEY.)... 

The amide group is readily hydrolyzed to acrylic acid, and this reaction is kinetically faster in base than in acid solutions (5,32,33). However, hydrolysis of N-alkyl derivatives proceeds at slower rates. The presence of an electron-with-drawing group on nitrogen not only facilitates hydrolysis but also affects the polymerization behavior of these derivatives (34,35). With concentrated sulfuric acid, acrylamide forms acrylamide sulfate salt, the intermediate of the former sulfuric acid process for producing acrylamide commercially. Further reaction of the salt with alcohols produces acrylate esters (5). In strongly alkaline anhydrous solutions a potassium salt can be formed by reaction with potassium / /-butoxide in tert-huty alcohol at room temperature (36). 

This process yields satisfactory monomer, either as crystals or in solution, but it also produces unwanted sulfates and waste streams. The reaction was usually mn in glass-lined equipment at 90—100°C with a residence time of 1 h. Long residence time and high reaction temperatures increase the selectivity to impurities, especially polymers and acrylic acid, which controls the properties of subsequent polymer products. 

Ionomer resins consisting of ethylene—methacrylic acid copolymers partially neutralized with sodium or zinc were commercially introduced in 1964 by Du Pont under the Sudyn trademark (1). More recently, a similar line of products, sold as Hi-Mdan resins, has been commercialized by Mitsui—Du Pont in Japan. lolon ionomeric resins, based on ethylene—acrylic acid, are produced by Exxon in Belgium. Ionomers containing about 1 mol % of carboxylate groups are offered by BP in Europe as Novex resins. Low molecular weight, waxy Aclyn ionomers are produced and sold by AHiedSignal. 

AUyl acetate can be obtained by the vapoi-phase reaction of propylene and acetic acid over a supported Pd catalyst (eq. 20) (110). Reaction of acrylic acid and propylene yields isopropyl acrylate (eq. 21), and catalytic reaction with acetic acid produces isopropyl acetate (eq. 22) (110). 

Acetic acid (qv) can be produced synthetically (methanol carbonylation, acetaldehyde oxidation, butane/naphtha oxidation) or from natural sources (5). Oxygen is added to propylene to make acrolein, which is further oxidized to acryHc acid (see Acrylic acid and derivatives). An alternative method adds carbon monoxide and/or water to acetylene (6). Benzoic acid (qv) is made by oxidizing toluene in the presence of a cobalt catalyst (7). 

Degenerate Explosion it was a free radical autocatalytic process and control was difficult, but manageable. The main disadvantage was that it produced as much or more acrolein as propylene oxide. Because no market existed for acrolein at that time, the project was abandoned. Within two years, the acrylic market developed and a new project was initiated to make acrolein and acrylic acid by vapor-phase catalytic oxidation of propylene. 

Acrylic is a generic name for derivatives of acrylic acid, of which methyl methacrylate is the most important. Polymerization is controlled to produce chain length of 800 to 3,000 monomer units. A small amount of plasticizer such as dibutyl phthalate may be added before bulk polymerization to assist in deep molding. The outstanding property of polymethyl metliacrylate is 0 transparency resistance to ultraviolet radiation from fluorescent lamps and ability to be... 

The 2-phenyl-2-ethyl-pentane-1,5-diacid-mononitrile-(1) of melting point 72° to 76°C, used as starting material in this process, can be produced for example from o-phenyl-butyric acid nitrile by condensation with acrylic acid methyl ester and subsequent hydrolysis of the thus-obtained 2-phenyl-2-ethyl-pentane-1,5-diacid-monomethyl ester-mononltrile-(l) of boiling point 176° to 185°C under 12 mm pressure. 

In nonrigid ionomers, such as elastomers in which the Tg is situated below ambient temperature, even greater changes can be produced in tensile properties by increase of ion content. As one example, it has been found that in K-salts of a block copolymer, based on butyl acrylate and sulfonated polystyrene, both the tensile strength and the toughness show a dramatic increase as the ion content is raised to about 6 mol% [10]. Also, in Zn-salts of a butyl acrylate/acrylic acid polymer, the tensile strength as a function of the acrylic acid content was observed to rise from a low value of about 3 MPa for the acid copolymer to a maximum value of about 15 MPa for the ionomer having acrylic acid content of 5 wt% [II]. Other examples of the influence of ion content on mechanical properties of ionomers are cited in a recent review article [7],... 

Okubo et al. [87] used AIBN and poly(acrylic acid) (Mw = 2 X 10 ) as the initiator and the stabilizer, respectively, for the dispersion polymerization of styrene conducted within the ethyl alcohol/water medium. The ethyl alcohol-water volumetric ratio (ml ml) was changed between (100 0) and (60 40). The uniform particles were obtained in the range of 100 0 and 70 30 while the polydisperse particles were produced with 35 65 and especially 60 40 ethyl alcohol-water ratios. The average particle size decreased form 3.8 to 1.9 /xm by the increasing water content of the dispersion medium. 

The liquid phase reaction of ethylene with carbon monoxide and oxygen over a Pd VCu " catalyst system produces acrylic acid. The yield based on ethylene is about 85%. Reaction conditions are approximately 140°C and 75 atmospheres ... 

The direct oxidation of propylene using air or oxygen produces acrolein. Acrolein may further he oxidized to acrylic acid, which is a monomer for polyacrylic resins. 

The main use of acrolein is to produce acrylic acid and its esters. Acrolein is also an intermediate in the synthesis of pharmaceuticals and herhicides. It may also he used to produce glycerol hy reaction with isopropanol (discussed later in this chapter). 2-Hexanedial, which could he a precursor for adipic acid and hexamethylene-diamine, may he prepared from acrolein Tail to tail dimenization of acrolein using ruthenium catalyst produces trans-2-hexanedial. The trimer, trans-6-hydroxy-5-formyl-2,7-octadienal is coproduced. Acrolein, may also he a precursor for 1,3-propanediol. Hydrolysis of acrolein produces 3-hydroxypropionalde-hyde which could he hydrogenated to 1,3-propanediol. ... 

There are several ways to produce acrylic acid. Currently, the main process is the direct oxidation of acrolein over a combination molybdenum-vanadium oxide catalyst system. In many acrolein processes, acrylic acid is made the main product by adding a second reactor that oxidizes acrolein to the acid. The reactor temperature is approximately 250°C ... 

Acrylic acid and its esters are used to produce acrylic resins. Depending on the polymerization method, the resins could he used in the adhesive, paint, or plastic industry. 

Acrylonitrile is mainly used to produce acrylic fibers, resins, and elastomers. Copolymers of acrylonitrile with butadiene and styrene are the ABS resins and those with styrene are the styrene-acrylonitrile resins SAN that are important plastics. The 1998 U.S. production of acrylonitrile was approximately 3.1 billion pounds. Most of the production was used for ABS resins and acrylic and modacrylic fibers. Acrylonitrile is also a precursor for acrylic acid (by hydrolysis) and for adiponitrile (by an electrodimerization). 

Isopropyl acrylate is produced by an acid catalyzed addition reaction of acrylic acid to propylene. The reaction occurs in the liquid phase at about100°C ... 

Much like the oxidation of propylene, which produces acrolein and acrylic acid, the direct oxidation of isobutylene produces methacrolein and methacrylic acid. The catalyzed oxidation reaction occurs in two steps due to the different oxidation characteristics of isobutylene (an olefin) and methacrolein (an unsaturated aldehyde). In the first step, isobutylene is oxidized to methacrolein over a molybdenum oxide-based catalyst in a temperature range of 350-400°C. Pressures are a little above atmospheric ... 

Three major non-polymer propylene derivatives are isopropanol, acetone, and acrylic acid. Isopropanol (isopropyl alcohol) is used mainly as a solvent. It has been made from propylene by reaction with sulfuric acid and water for at least the last 75 years, making its manufacture the oldest, still-running commercial organic chemical process. It is used in household rubbing alcohol because, unlike ethanol, it is unfit for human consumption even in small amounts. About 25 % of the isopropanol produced is used for making acetone, in competition with a route based on isopropylbenzene. 

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