Claim 1, the direct synthesis technology of rare earth organic compounds, is characterized in that: a, the composition of rare earth organic compounds is: a) at least one or two kinds of organic acids or/and organic esters and their mixtures, the dosage is 8 1 ~ 89 parts by weight, and the organic acids or/and esters refer to C6-C65438+. B) 1 1- 19 parts by weight of at least one or more than two or all of light rare earth oxides or their mixtures with purity of 90-99%, wherein the light rare earth oxide reO represents: Re is La, Ce, Pr, Nd, Y; C) 0.5-3 parts by weight of a catalyst, wherein the catalyst refers to acetic acid (glacial acetic acid), hydrogen peroxide, carbonic acid and oxalic acid; B, the technological conditions of the direct method are as follows: firstly, the organic acid or/and ester and their mixture are added into the reaction kettle according to the above formula, and then the catalyst of the above formula is added after melting, and the light rare earth oxide Re0 of the above formula is added into the reaction kettle at 60-10/0℃, and the reaction temperature is controlled at 90- 140℃.
1 & gt； Chemical name: sodium polysulfide sodium dipropane sulfonate (SP); Product features: white granular crystal, easy to absorb moisture, strong water solubility; Product use: SP is used as grain refiner in acidic copper plating bath to improve current density. When used in combination with M, N, PN, GISS and AESS, the effect is very obvious. Its application range is very wide, which can be increased or decreased with the temperature: the dosage is 0.0 15-0.04g/L in the range of 15℃-40℃, such as content. If it is too high, the coating will produce white fog, which will also cause bad low pressure area. A small amount of N can be added or electrolyzed. Basic parameters: SP is used as grain refiner in acidic copper plating bath to improve current density. When used in combination with M, N, PN, GISS and AESS, the effect is very obvious. Its application range is very wide, which can be increased or decreased with the temperature: the dosage is 0.0 15-0.04g/L in the range of 15℃-40℃, such as content. If it is too high, the coating will produce white fog, and it will also cause bad low pressure area. Polyallylamine (PAH) was synthesized by bulk polymerization with allylamine hydrochloride (AH) as monomer and ammonium persulfate/sodium bisulfite as redox initiator system. The structure and properties of the polymer were studied by Fourier transform infrared spectrometer (FTIR), nuclear magnetic resonance spectrometer (NMR) and thermogravimetric analyzer (TGA). At the same time, the effects of initiator dosage on polymerization conversion and relative viscosity of polymer were investigated. The results show that the characteristic absorption peak of carbon-carbon double bond at 998cm- 1 in infrared spectrum disappears, and the peak shape, peak area and chemical shift of polymer and monomer are obviously different in NMR spectrum, which proves that AH polymerizes to form PAH. The decomposition of PAH is divided into two stages, which is completely decomposed at 650℃ and has high thermal stability. With the increase of initiator dosage, the monomer conversion rate increases and the relative viscosity of polymer decreases. When the amount of initiator is 20% of the monomer mass, the monomer conversion and the relative viscosity of the polymer are 42.65438 0% and 65438 0.0348, respectively.
Polyallylamine hydrochloride; Bulk polymerization; Thermal stability; relative viscosity
Polyallylamine (PAH) is a polymer electrolyte with primary amine groups. Due to the high reactivity of amino groups, polycyclic aromatic hydrocarbons can be easily modified to obtain functional polymer materials, which can be used in papermaking [1], water treatment and metal complexation. It is also widely used in self-assembly [2-3], catalysis [4], membrane separation [5], exchange resin [6], hydrogel [7], microcapsule [8] and composite material [9]. Because the chain transfer of allyl compounds is serious in the process of free radical polymerization [10], especially the chain transfer is aggravated by the existence of amino groups, the direct polymerization of allylamine (AH) can not obtain PAH[ 1 1]. There are two main methods to synthesize PAH: one is chemical modification of polymer materials [12]; The second is the free radical polymerization of inorganic acid salts in allylamine [14- 15]. In the 1940s, Parker et al. [12] studied the catalytic hydrogenation of polyacrylonitrile to synthesize PAH, but the product structure was complex, and it often contained cyano, amino and imino groups. Panzer et al. [13] used polymer quaternary ammonium salt obtained by the reaction of polychloropropylene with trimethylamine as flocculant. Due to the limitation of reaction conditions of polymer chemical modification, only products containing a certain amount of amino groups can be obtained. In view of this, 1976 kabanov et al. initiated PAH in phosphoric acid with 60Co, but the conversion rate was low. 1984 Harada[ 14] found that water-soluble azo initiators such as 2,2'-azo-di -(2- methylpropylenediamine) hydrochloride are very easy to initiate allylamine polymerization in water with high conversion rate, but these initiators are expensive and large in dosage, and have not been applied in industry at present. However, European patent [15] reported that PAH could be obtained by allylamine polymerization with metal hydrochloride /H2O2 as initiator system and sodium pyrophosphate as complexing agent, but the degree of polymerization was not high. Based on the advantages and disadvantages of these methods, this paper adopts the second method to prepare PAH, that is, free radical polymerization of inorganic acid salts in allylamine. Because the initiator and monomer are easily available, the price is low, the reaction conditions are simple, and the conversion rate is high, high molecular weight PAH can be obtained.
2 experimental part
2. 1 reagents and instruments
Reagent used: acrylamide (Shandong Lu Yue Chemical Co., Ltd., content ≥ 99.5%); Concentrated hydrochloric acid (Tianjin Huadong Reagent Factory, AR); Potassium persulfate (K2S2O8, Tianjin Huadong Reagent Factory, AR) is refined by recrystallization from distilled water. Ammonium persulfate ((NH4)2S2O8, Tianjin (Hong Kong) Xintong Fine Chemical Co., Ltd., AR), refined by recrystallization with distilled water; Sodium bisulfite (NaHSO3, Tianjin Tianda Purification Material Fine Chemical Factory, AR); Methanol (CH3OH, Tianjin Huadong Reagent Factory, AR); Sodium hydroxide (NaOH, Tianjin North Tianyi Chemical Reagent Factory, AR); Deionized water.
Instruments used: Fourier transform infrared spectrometer (FT-IR, NICOLET380, Thermo electron Company, USA), superconducting nuclear magnetic resonance spectrometer (NMR, AVANCE400, BRUKER Company, Germany), thermogravimetric analyzer (TGA, Pyris 6, Perkin-Elmer Company, USA), Ubbelohde viscometer.
2.2 polymerization mechanism
Allylamine polymerization is a free radical chain homopolymerization reaction, and the chain transfer is serious during the polymerization process, so it is difficult to obtain high molecular weight PAH. In this experiment, allylamine was converted into hydrochloride, and amino group was changed into ammonium ion, which enhanced its electric absorption and was beneficial to polymerization. The thermal decomposition of redox initiator generates free radicals to initiate monomer polymerization, and the reaction formula is as follows:
2.3 Synthesis process
Add 26.5mL allylamine into a three-necked bottle, and dropwise add 3 1mL concentrated hydrochloric acid at 0-4℃ to obtain allylamine solution [16] with pH value of 5.0, and concentrate it to the required concentration (70%) under reduced pressure. Then, 20mL of the above solution was added into a three-necked bottle, heated to 50℃ under magnetic stirring, deoxygenated with nitrogen for 0.5h, then added with K2S2O8 (or (NH4)2S2O8) and NaHSO3 (molar ratio of substances 1: 1), and polymerized at 50℃ for 24h to obtain a yellow viscous liquid. Dropping viscous liquid into 120mL methanol, stirring, separating out pale yellow powdery solid, and performing suction filtration to obtain the product. Add a small amount of water to dissolve it, adjust the pH to weak alkalinity with 1mol/L NaOH solution, then add 200mL of water for vacuum distillation, and stop distillation when yellow viscous liquid is obtained. The solution was precipitated with methanol, then dissolved once with a small amount of water-methanol and filtered to obtain pale yellow powder. Drying at 50℃ in vacuum (vacuum degree 0.65438±0 MPa) for 24 hours, weighing and calculating the conversion rate.
2.4 Structural Characterization and Performance Testing
2.4. 1 determination of conversion rate:
Weigh the vacuum-dried product and calculate the conversion rate (c%) according to the following formula c %):c% = product quality/allylamine quality × 100%.
2.4.2 Infrared spectrum analysis:
The acrylamide solution and polymer were analyzed by infrared spectrum, and the samples were sampled by KBr tabletting method. Allylamine solution was coated on KBr sheet for Fourier transform infrared spectrum analysis.
2.4.3 NMR spectrum analysis:
Monomers and polymers were analyzed by 1HNMR, and D2O was used as solvent.
2.4.4 Thermal stability test of polymer:
In nitrogen atmosphere, the dried sample was heated from 30℃ to 800℃ at the rate of 20℃/min, and the thermogravimetric behavior of the sample was recorded.
2.4.5 Determination of relative viscosity of polymer:
The viscosity of polymer solution was measured by Ubbelohde viscometer. 0.25g of polymer was dissolved in 12.5mL NaCl solution with a concentration of 2mol/L, and transferred to a 25mL volumetric flask, and the volume was determined with deionized water. Keep it at 30℃ for 20min, and measure the flow time. Repeat for three times, and find the average relative viscosity number hr, hr=t/t0, where t and t0 are the flow time of the sample to be tested and 1mol/L NaCl solution in Ubbelohde viscometer respectively.
3 Results and discussion
3. 1 infrared spectrum analysis
When the wave number is about 3400cm- 1, it is an N-H stretching vibration peak. About 1600cm- 1 is the N-H in-plane deformation vibration peak; C-H deformation vibration peak is about1500 cm-1; 1 100cm- 1 is the C-N tensile vibration peak; In curve A, 998cm- 1 is the characteristic peak of deformation vibration of double bonds in CH2 = CH, and 946cm- 1 is the deformation vibration peak of C-H. The characteristic peak of 998cm- 1 in curve B disappears, indicating that double bonds are broken. By comparing the infrared spectra before and after polymerization, it can be seen that the characteristic peak of the double bond has disappeared after polymerization, indicating that the monomer has polymerized to form a polymer.
3.2 NMR * * vibration spectrum analysis
There are three kinds of hydrogen protons, among which the absorption peak with d of 5. 10ppm is the proton (a) absorption peak on methylene linked by double bonds, and the absorption peaks of two hydrogen protons split into four peaks due to different chemical environments; The absorption peak with d of 5.85ppm is the proton (b) absorption peak on methylene; The absorption peak with D of 3.08ppm is the proton (C) absorption peak on the methylene group connected to the amino group. The ratio of the integrated areas of the three absorption peaks is consistent with the ratio of the number of three hydrogen atoms in the molecular formula. As can be seen from Figure 3, there are three kinds of protons, among which the absorption peak with d of 1.43ppm belongs to the proton (a) absorption peak of methylene -CH2- in the main chain; The absorption peak with d of 1.98ppm belongs to the proton (b) absorption peak of methyl -CH- on the main chain; The absorption peak with D of 2.95ppm belongs to the proton (C) absorption peak of methylene -CH- linked nitrogen, which is due to the large electronegativity of nitrogen, resulting in shielding effect and increasing the chemical shift of the vibration frequency of * * * to the low field. The ratio of the integrated areas of these three absorption peaks is consistent with the ratio of the number of three hydrogen atoms in the molecular formula of the polymer. The integral areas of various protons are obviously different, and the peak positions of polymers and monomers change. The absorption peak shape of polymer is obviously different from that of monomer, which indicates that allylamine has been polymerized.
3.3 Thermogravimetric Analysis of Polymers
Thermogravimetric curve of polymer (initiator system: (NH4) 2S2O3/nahso3, initiator dosage 65438+ 00% of monomer mass, reaction temperature 50℃, reaction time 24h). From the thermogravimetric curve, the polymer began to lose weight around 100℃, which may be caused by small molecular solvent water. The weight loss of polymer is obviously divided into two stages. In the first stage, from about 280℃ to about 400℃, the weight loss rate is about 52%, which may be due to the first decomposition of polymer side chain (-NH3Cl). In the second stage, it almost completely decomposes from about 400℃ to about 650℃, and the weight loss rate is about 40%, which may be caused by the decomposition of polymer backbone. The weight loss rate data of two stages is equivalent to the molecular weight ratio of polymer main side chain. Generally speaking, the polymer has good thermal stability.
3.4 Influence of initiator dosage on conversion rate
After the decomposition of initiator, only a part of initiator is used to initiate monomer polymerization, and a part of initiator is lost due to induced decomposition and/or side reaction accompanied by cage effect. Therefore, the amount of initiator directly affects the conversion and molecular weight. In this experiment, the influence of initiator mass on the conversion rate was investigated when the initiator mass was 2%, 5%, 10%, 15% and 20% of the monomer mass, respectively (Figure 5-5). (The concentration of allylamine solution used is 70%).
With the increase of initiator dosage, the monomer conversion rate increased obviously. When the amount of initiator ((NH4) 2SO8/nahso3 system) is 20%, the conversion rate can reach 42. 1%. According to the micro-kinetics of free radical polymerization, r = RP = KP (fkd/kt)1/2 [I]1/2 [m]. This is because the higher the concentration of initiator, the higher the rate of forming primary free radicals, the higher the initiation rate, the more monomer free radicals produced by primary free radicals and monomer addition, and the higher the total polymerization rate. In this way, the rate of free radical polymerization between monomers and other monomers will be higher, so the monomer conversion rate will also be improved. This accords with the law of free radical polymerization.
Different initiator systems have different conversion rates. When the amount of initiator is more than 5%, the conversion rate of K2S2O8/NaHSO3 system is lower than that of (NH4) 2SO8/nahso3 system. This is because the solubility of K2S2O8 is less than that of (NH4) 2SO8, so with the increase of initiator dosage, the improvement of conversion rate is relatively small. Therefore, (NH4)2S2O8/NaHSO3 system was used as redox initiator system in this experiment.
3.5 Influence of initiator dosage on relative viscosity of polymer
Relationship between relative viscosity of polymer and amount of initiator. As can be seen from the figure, with the increase of initiator concentration, the relative viscosity of the polymer decreased obviously. Because the molecular weight of polymer is directly proportional to viscosity, the molecular weight of polymer also decreases with the increase of initiator concentration. According to the formula n = KP [m]/2 (fkdkt)1/2 [I]1/2, the kinetic chain length is inversely proportional to the square root of initiator concentration, so the more initiator is used, the more primary free radicals are generated in the chain initiation stage, and the shorter the polymer chain is generated in the chain termination stage, that is, the kinetic chain length n will decrease and the molecular weight will decrease. This is also in line with the law of free radical polymerization.
4 conclusion
(1) polyallyl ammonium hydrochloride was synthesized by bulk polymerization with K2S2O8/NaHSO3 or (NH4) 2SO8/nahso3 as initiator. When (NH4) 2SO8/nahso3 system is used as initiator, the monomer conversion rate is high, and when the amount of initiator is 20% of the monomer mass, the conversion rate can reach 42. 1%.
(2) The disappearance of the characteristic absorption peak of carbon-carbon double bond at 998cm- 1 in infrared spectrum and the obvious difference in peak shape, peak area and chemical shift between polymer and monomer in NMR spectrum all prove that PAH is generated by AH polymerization.
(3) 3) The weight loss of PAH is obviously divided into two stages: the first stage may be caused by the decomposition of polymer side chains; The second stage may be caused by the decomposition of polymer backbone. The weight loss rate of the two stages is equivalent to the molecular weight ratio of the polymer main side chain.
(4) With the decrease of initiator dosage, the relative viscosity and molecular weight of the polymer increased.
Adding a small amount of n or electrolytic treatment. Chemical name: sodium polysulfide sodium dipropane sulfonate (SP)