Cationic polyacrylamide production process
PAM for short, the structural formula is [-CH2-CH(CONH2)] N -, the molecular weight between 4-20 million. Polyacrylamide mainly has two kinds of commodity forms, one is the appearance of white or slightly yellow powder, soluble in water, the speed is very slow, increase the temperature can slightly promote dissolution, but the temperature shall not exceed 50℃, in order to prevent molecular degradation, difficult to dissolve in organic solvents. Another is colorless viscous colloid, as well as polyacrylamide emulsion (Shanghai synthetic resin Research Institute). Neutral, non-toxic. Polyacrylamide stored in a cool, ventilated, dry warehouse, moisture, light, heat. The storage time should not be too long. Polyacrylamide is divided into cationic type, anionic type, amphoteric ion and non-ionic type according to structure.
Cationic polyamide (CPAM)
Cationic polyacrylamide (CPAM) is a kind of cationic units and acrylamide copolymer of non ionic units, with its molecular chain can ionization of positive group (CONH2), in the water can be ionized into polycation and small anion, and dispersed in the solution of suspended particle adsorption and bridging, has strong flocculation. Cationic polyacrylamide is widely used in water treatment and metallurgy, paper making, petroleum, chemical industry, textile, mineral processing and other fields, as a thickener, flocculant, drag reducer, with gel, sedimentation, reinforcement and other functions. The molecular weight of CPAM is generally lower than NPAM and APAM, especially suitable for the dewatering treatment of municipal sewage, municipal sludge, papermaking sludge and other industrial sludge.
In the synthesis of cationic polyacrylamide more commonly used cationic monomers are methyl acryloxyethyl trimethylammonium chloride (DMC), acryloxyethyl trimethylammonium chloride (DAC), dimethyl diallyl ammonium chloride (DMDAAC), acryloyl aminopropyl trimethylammonium chloride (AMPTAC), methacrylate -2-(N, N-dimethylamino) ethyl ester (DM), acrylic acid -2-(N, N-dimethylamino) ethyl ester (DA), etc. DMDAAC, DAC and DMC are more commonly used.
(1) of DMDAAC
Dimethyl diallyl ammonium chloride is a high purity, polymerization grade, quaternary amine salt, high charge density cationic monomer, containing trace sodium chloride and other impurities (controllable range), molecular formula is C8H16NCl, molecular weight. The molecular structure contains alkenyl double bonds, which can form linear homopolymers and various copolymers through various polymerization reactions. DMDAAC as cationic monomer through homopolymerization or copolymerization to form polymer. In the process of water treatment can be used for decolorization , flocculation and purification, efficient and non-toxic; Among daily chemicals, carding agents, wetting agents and antistatic agents can be used for shampoo; In oilfield chemicals, it can be used as flocculant, water blocking agent, etc.
(2) The Methyl acryloxyethyl trimethyl ammonium chloride (DMC)
Methyl acryloxyethyl trimethyl ammonium chloride (DMC), chemical formula CH2=C(CH3)COOCH2CH2N (CH3)3C L -. DMC is a cationic monomer, which can be homopolymerized or copolymerized with other monomers to prepare a cationic polymer. The polymer has strong polarity and affinity to anionic substances, so it can be widely used as a cationic flocculant. It can be used in sludge dewatering process of sewage treatment plant and wastewater treatment of papermaking, coal flotation, printing, dye and other industries. In addition, DMC can also be used to produce acid resistant superabsorbent resins and oilfield chemicals.
(3) The Acryloxyethyl trimethyl ammonium chloride (DAC)
Acryloxyethyl trimethyl ammonium chloride (DAC) is a quaternary ammonium salt produced by the reaction of dimethylaminoethyl acrylate and chloromethane, soluble in water. Molecular formula: CH2=CHCOOCH2CH2N(CH3)3Cl-. Mainly used for homopolymerization or copolymerization with acrylamide to prepare cationic polymer flocculant. It is now preferred to be replaced by methylacryloxyethyl trimethylammonium chloride.