|Company Name:||J & K SCIENTIFIC LTD. |
|Acrylamide Chemical Properties|
|Melting point ||82-86 °C(lit.)|
|Boiling point ||125 °C25 mm Hg(lit.)|
|density ||1,322 g/cm3|
|vapor density ||2.45 (vs air)|
|vapor pressure ||0.03 mm Hg ( 40 °C)|
|refractive index ||1.460|
|Fp ||138 °C
|storage temp. ||2-8°C|
|solubility ||H2O: 50 mg/mL at 20 °C, clear, colorless|
|Water Solubility ||SOLUBLE, 216 g/100 mL|
|Sensitive ||Light Sensitive|
|Stability:||Unstable. Do not heat above 50C. Explosive. Incompatible with acids, bases, oxidizing agents, reducing agents, iron and iron salts, copper, aluminium, brass, free radical initiators. Air sensitive. Hygroscopic.|
|CAS DataBase Reference||79-06-1(CAS DataBase Reference)|
|NIST Chemistry Reference||Acrylamide(79-06-1)|
|EPA Substance Registry System||2-Propenamide(79-06-1)|
|Acrylamide Usage And Synthesis|
|Polyacrylamide material||Acrylamide is a white crystalline chemical substance and is a raw material for production of polyacrylamide. |
Polyacrylamide (Polyscrylamide) briefly called PAM, is commonly known as flocculants or aggregation agent. It is divided into anionic, cationic and non-ionic types and is a linear polymer having a molecular weight between 400-2100 million. The solid product appears white or slightly yellow particles; it is soluble in water. Its liquid form is colorless viscous colloidal like, soluble in water, and easily decomposed when the temperature exceeds 120 °C. It can especially flocculating, precipitation and separation effects on the organic matter and red mud suspended in acidic or alkaline water with low applied amount, low cost of water which is not comparable by other kind of flocculating products.
Anionic type is mainly used for treating living and production water, industrial and urban sewage. It can also be applied to the flocculation of red mud and mud-liquid separation during the process of the preparation of alumina oxide.
Cationic has a relative high molecular weight; it is mainly used for the flocculation and precipitation of water suspension and suspended matter; it is difficult for flocculation of organic suspension in acid and acidic solution.
In this case, the cationic type can effectively carry out flocculation and sedimentation, exhibiting its outstanding performance.
Its 0.1-0.2% aqueous solution must be prepared by water of PH≤7; it is easily be hydrolyzed as diluted solution. You should either use it immediately once it has been prepared or at least use it up just at that day. It is not suitable for long-term storage.
|Product Features||Solid acrylamide (abbreviated AM) is usually colorless and transparent flaky crystals with pure product being white crystalline solid which is soluble in water, methanol, ethanol, propanol, and slightly soluble in ethyl acetate, chloroform, and benzene. It can be hydrolyzed to acrylic acid in acidic or alkaline environment. |
Acrylamide is a large class of the parent compound of monomers including methacrylamide, the AMPS (anionic monomer, 2-Acraylamide-2-Methyl Propane Sulfonic Acid), the DMC (cationic monomer, methyl-acryloyloxyethyl trimethyl ammonium chloride) and N-substituted acrylamide compound.
Occupational exposure is mainly seen in acrylamide production and the synthesis of resins, adhesives, etc. It is also possible for contract in underground construction, upon soil improvement, painting, paper industry and garment processing.
At daily life, people can touch it in smoking, drinking and eating the starchy foods processed at high temperature.
The above information is edited by the chemicalbook of Dai xiongfeng.
|Synthesis||At the end of 19th century, people had first made acrylamide using propylene chloride and ammonia. |
In 1954, American Cyanamid Company uses sulfuric acid hydrolysis of acrylonitrile for industrial production.
In 1972, Mitsui Toatsu Chemicals, Inc. had first established the skeleton copper (see the metal catalyst) catalyzed acrylamide synthesis via acrylonitrile hydration. Then other countries have developed different types of catalyst and applied this technology for industrial production.
In 1980s, Japanese Nitto Chemical Industry Company has achieved that using biological catalyst for industrial production of acrylamide from acrylonitrile.
Sulfuric acid hydration way
Acrylonitrile and water is hydrolyzed into acrylamide sulfate in the presence of sulfuric acid and then treated neutralized liquid ammonia to give ammonium sulfate and acrylamide:
CH2 = CHCN + H2O + H2SO4 → CH2 = CHCONH2 • H2SO4 CH2 = CHCONH2 • H2SO4 + 2NH3→ CH2 = CHCONH2 + (NH4) 2SO4
The disadvantage of this method is by-producing a large number of low-value, low fertilizing efficacy-ammonium sulfate and causing serious sulfuric acid corrosion and pollution.
Catalytic hydration way
Acrylonitrile is reacted with water by the copper-based catalyst to have liquid phase hydration reaction at 70~120 °C at 0.4MPa pressure.
CH2 = CH-CN + H2O → CH2 = CHCONH2; Filter the catalyst after reaction catalyst; recycle the unreacted acrylonitrile; acrylamide solution was concentrated and cooled to give crystals. This is a simple method with the yield up to 98%.
|Toxicity||Acrylamide is moderately toxic and have a stimulating effect on eyes and skin. It can be absorbed through the skin, respiratory and digestive tract, and have in vivo accumulation effect which mainly affects the nervous system with acute poisoning being very rare. |
Frequently close contact can cause sub-acute onset such as drowsiness and cerebellar dysfunction, manifested as eye level tremors, slurred speech, and unstable finger-nose, knee-shin test, rotation movement disorders, unsteady gait and so on. Sensorimotor polyneuropathy disease may occur after 2 weeks manifested as numbness, prickly, weakness in lower limb. Tuning fork vibration sense and achilles tendon reflexes have a value of early diagnosis. EMG examination revealed: distal sensory potentials significantly decreased with neurogenic damage; it may be associated with much spontaneous denervation potentials.
Long-term low-level exposure can cause chronic poisoning manifested as headache, dizziness fatigue, drowsiness, prickly fingers, and numbness, often accompanied by palm redness, scaling, palms and foot sweating, and with further development into limb weakness, muscle paining, and cerebellar dysfunction, staggering gait, and being prone to forward dumping. Neurological examination can identify the reduction or loss of deep reflex, reduction of tuning fork vibration sense and position sense, and positive symptoms in Romberg test and so on. EMG examination showed similar behavior as sub-acute toxicity while EEG abnormalities can be mild.
The most interesting issue about chronic toxicity of acrylamide is its carcinogenicity. Study have confirmed that acrylamide can be absorbed into the body through a variety of ways, including through the digestive tract giving the fastest absorption rate; it is widely distributed in body tissues including breast milk, so there may exist the possibility of transmission between mother and child. After it enters into the body, it is converted into glycidamide through the action of cytochrome oxidase. Glycidamide is more easily to bind with the guanine on DNA to form adducts, causing the genetic damage and mutations.
Animal studies have found that acrylamide can cause multiple organ tumors in rats or mice, such as breast, thyroid, testes, adrenal glands, central nervous system, oral cavity, uterus, and pituitary tumors. But there is no sufficient epidemiological evidence that the dietary intake of the product has significant correlation with some human tumors. International Cancer Research (IARC) has evaluated the carcinogenicity of acrylamide, it was listed as a category 2 carcinogen (2A), meaning that it may be carcinogenic to human beings. The main basis is that it can be converted to carcinogenic active metabolite epoxypropionamide inside animals and humans.
|Control and Prevention||1. Occupational contacts should used reformed process and take the means of engineering and technical to reduce the concentration of acrylamide in the air of workplace; at the same time, strengtheni personal protection such as wearing masks, gloves, protective clothing and shoes to prevent or reduce their access to the body. |
2. for daily life, try to avoid over-cooking food, such as a extra-high heating temperature or a extra heating time. Advocate a balanced diet, reduce the intake of fried foods and high fat food, eat more fruits and vegetables, and do not smoke.
3. due to the widely spred of fried food in China; countries should strengthen the monitoring and control of dietary acrylamide, carry out China's population acrylamide exposure assessment, and study and explore the approach for reducing its content in the processed food.
|Formation in food||Acrylamide is mainly formed during the heating and cooking of the high-carbohydrate, low-protein plant foods (120°C or more). The optimum temperature is 140-180 °C for its formation while it can’t be dected before food processing; at lower processing temperatures, such as boiled with water, the amoun of acrylamide is quite low. Water content is also an important factor affecting their formation, especially in the final stage of baking and frying when the moisture reduces, and the surface temperature increases, cuasing formation of higher level with the exception of coffee for which the acrylamide content even decreases in the latter baking. The major precursors of acrylamide is free aspartate (potatoes and cereals representation of amino acids) which, together with reduced sugar have Maillard reaction (a non-enzymatic browning reaction occurs between amino acids and reducing sugars between) to generate acrylamide. The formation of acrylamide in foods is relatively stable with the exception of coffee for which the content may even decrease with prolonged storage time.
|The content in food||Since the formation of acrylamide is relate to the cooking process, temperature, time, moisture, etc., and therefore different ways and processing conditions of different food will cause varied amout of acrylamide. Its amount can greatly vary even for the same kinds products produced in different batches. In the 64 th meeting of JECFA, there are 6752 sets of data of acrylamide content in food from 24 contries in 2002--2004 in which 67.6% of the data comes from Europe, 21.9% from South America, 8.9% of the data from Asia and 1.6% of the data from the Pacific Ocean. Investigated data include breakfast cereals, potato products, coffee and similar products, milk, sugar and honey products, vegetables and beverages major consumer foods; amont these kinds of food, three types of food containing relative high amout of acrylamide are: high-temperature processed potato products (including potato chip, chips, etc.), with an average content of 0.477 mg/kg, the highest content was 5.312 mg/ kg; coffee and similar products with the average content of 0.509 mg/kg and the highest content of 7.3 mg/kg; breakfast cereals with the average content of 0.313 mg/kg and the highest content was 7.834 mg/kg; acrylamide levels in other types of basic foods are kept at 0.1 mg/kg or less.|
Nutritional information provided by the Food Safety Institute of China Disease Prevention and Control Center showed that in more than 100 monited samples, the order of the levels of acrylamide are: potato fried foods with the average content of 0.78 mg/kg and the highest content of 3.21 mg/kg; cereals fried food average content of 0.15 mg/kg with the highest content of 0.66 mg/kg; cereals, baked goods with an average content of 0.13 mg/kg and the highest content of 0.59 mg/kg; other foods, such as instant coffee (0.36 mg/kg), barley (0.51 mg/kg), and corn tea (0.27 mg/ kg). Accoring to the results of these limited samples, the acrylamide content in China's food similar to that in other countries’ food.
|Ptential intake of acrylamide among population||According to the estimation of the acrylamide intake of world's 17 countries, average intake of general population is 0.3-2.0μg/kg bw/day; for the 90-97.5 percentile of the high intake population, the intake amount is 0.6-3.5μg/kg bw/day, for the 99th percentile of the high intake group is 5.1μg/kg bw/day. In per body weight, children's intake is 2-3 times as high as adults. Wherein the main source of food of acrylamide are: fries potatoes (16-30%), potatoes chips (6-46%), coffee (13-39%), biscuits (10-20%), bread (10-30%) with the rest all being less than 10%. JECFA, according to the intake of each country, claims that the average human intake amout is approximately 1μg/kg bw/day, while high-level consumer has approximately 4μg/kg bw/day, including children. Since China is still lack of enough data on the acrylamide content in various types of foods, and the exact intake amout of these food, therefore, it is still not possible for determining the level of exposure to the population. However, because of the high content of acrylamide in fried potato food, coffee and baked food cereals and the fact that the intake of these levels of food in our population is not higher than other countries, the intake levels of China's population intake the levels should not be higher than that level evaluated in JECFA.
|Polymerization||For polymerization of acrylamide, people generally applies chemical catalytic systems or photocatalytic systems. |
(1) Chemical catalyst system: chemical catalytic polymerization of acrylamide is done in the systems containing the trigger and accelerator. Trigger reagents participating the reaction include ammonium persulfate (or potassium persulfate) and hydrogen peroxide while the accelerator includes dimethylamine propionitrile and so on. Because the polymerization of acrylamide can performed under both acidic or alkaline conditions, so the choice of trigger and accelerator should be changed with pH.
When the aqueous solution of acrylamide (Arc), cross-linking agent (Bis) and tetramethylethylenediamine (tetramethyl ethylene diamine, TEMED) is added into ammonium persulfate (ammoniumpersulfate, AP), AP [(NH4) 2S20s] immediately generate radical (S: OU-2S07), after the reaction between Arc and the free radicals, then it becomes "activate", activated Arc connects with each other to form a long chain poly. The solution containing this polymer chain, although is sticky but can’t form a gel and can form into a gel only when Bis is also presented. In the AP-TEMED catalyzed system, the initiating polymerization rate between Arc and Bis is positively proportional to the square root of the concentration of AP and can occur rapidly under alkaline conditions. For example, the complete polymerization of 7% Arc, only needs 0.5 h upon pH8.8; however, needs 1.5 h upon pH4.3. In addition, temperature, oxygen molecules and other impurities will also affect the rate of polymerization. Usually faster polymerization occurs at room temperature than at 0 °C; Solution subjecting to pre-pumping also has faster polymerization rate than that without pre-puming.
(2) Photocatalytic System: This catalysis of this system is vitamin B2. Photo-polymerization process is catalyzed at light excitation. Vitamin B: in the presence of oxygen and ultraviolet light, can produce products containing free radicals whose function is similar as AP agent described above. The mixture is usually placed next to a fluorescent lamp where the reaction can take place. When using Vitamin B2 for catalyzing, TEMED is not demaned, but adding it can accelerate the rate of polymerization. Gel formed by photo-polymerization is milky white like with poor transparency. The advantage of using this catalyst is that it needs a very small amount (1ml/100mi) without any adverse effect on the analysis of samples; polymerization time can be extended or shortened by chaning the light intensity and time.
The apertube of chemical polymerization is smaller thant that of photo-polymerization. The reproducibility and transparency is also better for the former one than the latter one. However, the trigger of the chemical polymerization, AP, is a strong oxidizing agent, tend to cause loss of activity of certain protein molecules if remaining in the gel or cause distortion on the electrophoresis pattern.
|Glue recipe||2099PVA 10Kg acrylamide 10KG.|
Add water and increase the temperature bto 95°C to dissolve the PVA and then cool to 85°C, when propylamine is added, and then cool to about 70°C; add 22 g of ammonium persulfate, stop striing and have automatic reaction for 5-6 hours with water being added to 1000KG.
|Chemical Properties||It is odorless and colorless crystal. It is soluble in water, ethanol, acetone, ether, and methyl chloroform, and slightly soluble in toluene but insoluble in benzene.
|Uses||1. It can be used as a monomer of polyacrylamide. Its polymer or copolymer is used as chemical grouting materials, soil conditioners, flocculants, adhesives and coatings. |
2. Polyacrylamide, when used as a kind of additive, can improve the oil recycling efficiency. When used as flocculants, it can be used for sewage treatment. It can also be used as a paper strength agent.
3. Acrylamide is the most important products in acrylamide and methacrylamide-based products. Since its application in industry in 1954, the demand gradually increase. It is mainly used for the preparation of water soluble polymers which can be used as additives to improve oil recovery; as a flocculant, thickening agents, and paper additives. A small amount of acrylamide is introduce the hydrophilic center into the lipophilic polymer to improve the viscosity, increase the softening point and improve anti-solvents ability of resin, and can aso introduce a center for the coloring property of dye. Acrylamide is also often used as a component of the photopolymer. For the vinyl polymer, its crosslinking reaction can take advantage of this kind of reactive amide groups. Acrylamide can co-polymerizze with certain monomers such as vinyl acetate, styrene, vinyl chloride, vinylidene chloride, and acrylonitrile to obtain a polymer with a variety of applications.
The main application areas: (1) used for the oilfield; the materials can be used in oilfield injection of wells for adjustment of the injection profile. Mix this product with initiator, and deaerator and inject into the high permeability layer part of water wells. This will lead the formation of high-viscosity polymer unearth of the stratum. This can plug the large pore, increase the swept volume of oil, and enhance the oil recovery. In addition, the product polymer or copolymer can be used for tertiary oil recovery, fracturing, water shutoff, drilling mixing process and chemical grouting. (2) It can be used as flocculants. Its partially hydrolyzed product and its graft copolymer of methyl cellulose can be used in wastewater treatment and sewage treatment. (3) Soil conditioner; using the hydrolyzed product as soil amendments can aggregate soil and can improve air circulation, water permeability and water retention. (4) Modification of fiber and resin processing; using acrylamide for carbamylation or graft polymerization can improve the resin arrangement of a variety of fiber containing synthetic fiber, as well as for warp and printing paste in order to improve the basic physical properties of fabrics as well as preventing wrinkle, shrink and keeping a good hand feeling. (5) It can be used as paper enhancer; copolymer of acrylamide and acrylic acid or partial hydrolysis products of polyacrylamide can be used as paper strength reinforcing agent for either replacing or combining with starch, and water-soluble amino resin. (6) it can be used as an adhesive agent including glass fiber adhesive agent with the combination of phenolic resin and polyacrylamide solution, as well as pressure sensitive adhesive combined with synthetic rubber.
4. It is the raw material for producing polyacrylamide and related products.
5. It can be used as the monomer of polyacrylamide. Its polymer or copolymer can be used as chemical grouting materials, soil conditioners, flocculants, adhesives and coatings. Polyacrylamide, as an additive, can improve oil recovery. As a kind of flocculants, it can be used for waste water treatment as well as paper strength enhancer can. It is the raw material for producing polyacrylamide and related products. It can also used for determining the relative molecular weight of acid.
|Production methods||1. Acrylonitrile sulfate hydration; Acrylonitrile and water is hydrolyzed into acrylamide sulfate in the presence of sulfuric acid and then treated neutralized liquid ammonia to give ammonium sulfate and acrylamide: The reaction products further undergoes filtering and separation. Crystallize the filtrate, dry to obtain the final product. The disadvantage of this method is by-producing a large number of low-value, low fertilizing efficacy-ammonium sulfate and causing serious sulfuric acid corrosion and pollution. This method can produce by-products of 2280 kg ammonium sulfate in per tons of acrylonitrile.Material consumption amount: Acrylonitrile (100%) 980kg/t, sulfuric acid (100%) 200kg/t, ammonia (100%) 700kg/t. |
2. Direct hydration of acrylonitrile: acrylonitrile is directly hydrated by water with copper being the catalyst at 85-125 °C and 0.3-0.4MPa pressure. The yielding aqueous solution of acrylamide (containing only small amounts of by-products) can be directly sold as a finished product. This method avoids acrylamide dust pollution and is advantageous for labor protection for using aqueous solution. Reference Product Specifications: appearance: white flakes or powder. With first-grade product containing content ≥95%; Secondary-grade content ≥90%; grade III content ≥85%.
3. Enzyme catalysis; at room temperature transfer the acrylonitrile solution into the fixed-bed reactor containing bacteria catalyst; after the reaction, 100% of acrylonitrile is converted into acrylamide. After isolation and even without the necessity of refining and concentration, we can get the acrylamide industrial products.
4. Concentrated sulfuric acid hydration method: mixture containing sulfate, phenothiazine (polymerization inhibitor), and water is added to the reactor; stir slowly with dropping acrylonitrile After the addition is completed, raise the temperature to 95~100 °C, keep the temperature for 50 min. Cool to 20~25 °C, dilute with an appropriate amount of water, neutralize with sodium carbonate, filtrate to obtain aqueous acrylic acid solution. Further cool and crystallize, separate, dry to obtain the completed products.
5. Catalytic hydration method; acrylonitrile and water undergoes liquid phase hydration in the presence of copper-based catalyst; It is generally used for continuous production with the reaction temperature being 85~120 °C, reaction pressure being 0.29~0.39 MPa, feed concentration of 6.5%, airspeed being 5 L/ h, the conversion rate being 85%, and selectivity being about 95% and the concentration of acrylamide in the reaction being 7% to 8%. Aqueous solution obtained by this method may be directly used as the product for sale.
|Chemical Properties||White crystals|
|Usage||Used as chemical intermediate in production of polyacrylamides, for use in protein electrophoresis (PAGE), synthesis of dyes and copolymers for contact lenses. It is reasonably anticipated to be a hum
|Toxicity grading||Highly toxic
|Acute toxicity||Oral-rat LD50: 124 mg/kg; Oral-Mouse LD50: 107 mg/kg
|Stimulus data||Skin-rabbit 500 mg/24 hr Mild; Eyes-rabbit 100 mg/24 hours of moderate
|Flammability and hazard characteristics||Combustible upon fire; decomposition at high temperature; cause emission of fumes of nitrogen oxide
|Storage Characteristics||Treasury: ventilation; low-temperature; dry; separately stored from oxidants, acids and food and chemical additives.
|Extinguishing agent||Water spray, foam, CO2, sand.
|Professional standards||TWA 0.3 mg/m³; STEL 0.9 mg/m3|
|General Description||A solution of a colorless crystalline solid. Flash point depends on the solvent but below 141°F. Less dense than water. Vapors heavier than air. Toxic oxides of nitrogen produced during combustion. Used for sewage and waste treatment, to make dyes and adhesives.|
|Air & Water Reactions||Acrylamide is very soluble in water. The solvent is not necessarily water soluble.|
|Reactivity Profile||ACRYLAMIDE SOLUTION reacts with azo and diazo compounds to generate toxic gases. Flammable gases are formed with strong reducing agents. Combustion generates mixed oxides of nitrogen (NOx). Spontaneous, violent polymerization occurs at the melting point (86°C of the undissolved solid [Bretherick, 5th ed., 1995, p. 428].|
|Health Hazard||Inhalation or contact with material may irritate or burn skin and eyes. Fire may produce irritating, corrosive and/or toxic gases. Vapors may cause dizziness or suffocation. Runoff from fire control or dilution water may cause pollution.|
|Acrylamide Preparation Products And Raw materials|