|Title of Invention||
"A PROCESS FOR PREPARATION OF COPPER LIGNIN COMPLEX "
|Abstract||A process for the preparation of copper lignin complex A and B, wherein preparation of complex A comprises in adding a saturated solution of CuSo4 5H2O to a solution of dried lignin, stirred with heating till complete precipitation, and complex B comprises in dissolving lignin in an alkaline solution and refluxed with a solution of sodium sulphite and sodium carbonate, adding a saturated solution of copper sulphate, stirred with heating till complete precipitation of the complex.|
|Full Text||This invention relates to lignin copper complex-A and B which may advantageously be employed as wood preservative.
BACKGROUND OF INVENTION
Non-durable and plantation woods are subjected to deterioration and need chemical protection when, exposed to outdoors, in soil contact. Very good results are obtained with different commercial products as biocides (CCA salts, creosote, chlorinated phenols), however they present environmental draw back due to their toxicity. Over the past three decades, there has been substantial global awareness of the dangers posed to the wood treatment workers by most of the conventional proprietary wood preservatives. Some of the chemicals used in conventional wood preservatives, which are not fixed properly, are harmful to the human beings and environment. Some of the conventional wood preservatives contain toxic elements like arsenic, chromium and few chloro-derivatives like PCP, which are hazardous in nature.
Fernandez, A.N. has reported the biocide quality of organosolv lignin extracted with formic acid-acetone. Three types of lignin were treated with copper (II) sulfate solution (crude lignin, purified lignin and carboxymethylated lignin). Wood samples were impregnated by double vacuum process in acetone medium and the highest retention (1.04 kg/m3) was reached with purified copper lignin. The wood samples were exposed, to promote the growth of special mould, wood samples without treatment were attacked very fast in relation to those treated with the test products. The test results were not so successful, because all the samples were contaminated with moulds before completing one-month exposure. Another study showed that double impregnation of wood with lignin and copper gave encouraging results. The only problem was that double impregnation increased the cost of treatment.
OBJECTS OF THE INVENTIQN
An object of this invention is to propose wood preservative of ammoniacal based
efficacious copper lignin complexes.
Another object of this invention is to propose wood preservative of ammoniacal based efficacious copper lignin complexes, which is eco friendly.
Yet another object of this invention is to propose wood preservative of ammoniacal based efficacious copper lignin complexes, which is cost effective.
Still another object of this invention is to propose wood preservative of ammoniacal based efficacious copper lignin complexes, which is efficient.
DESCRIPTION OF INVENTION
According to this invention there is provided a process for the preparation of copper lignin complex A which comprises in adding a saturated solution of CvSo4 5H2O to a solution of dried lignin till complete precipitation.
The solution of dried lignin comprises an alkaline solution. The complex was stirred with heating till completion of reaction.
Further, according to this invention there is provided a process for the preparation of copper lignosulfonate complex B which comprises in dissolving lignin in an alkaline solution and refluxed with a solution of sodium sulphite and sodium carbonate, adding a saturated solution of copper sulphate till complete precipitation of the complex.
The saturated solution of copper sulphate was added till complete precipitation and stirred with heating.
Isolation of Alkali lignin: Black liquor was prepared by pulping the wheat straw using soda process i.e. NaOH alone with 12.5% chemical charge during cooking. -Black liquor obtained after pulping of wheat straw was used in the study. The lignin was isolated by acidification of black liquor using IN hydrochloric acid.
The precipitated lignin was separated by centrifugation; material was washed repeatedly with water to free it from chloride ions. The centrifuged .material was dissolved in dioxane solution (lignin dioxane 1:10 W/V). The solution was kept overnight and filtered. The residue was rejected and the filtrate was poured drop wise in vigorously stirred diethyl ether. The precipitated lignin was collected and dried over anhydrous sodium sulfate under reduced pressure-Preparation of copper lignin complex -A
Saturated solution of CuSO4 5H20 (A.R. grade) was added slowly in slightly alkaline solution of dried lignin (lOgm) till complete precipitation occurred. During the preparation of lignin Copper complexes it was observed that the precipitate was gel like when low amount of Copper sulphate was added but when higher amounts of Copper sulphate was added, the amount of Copper -lignin precipitate increased which was easily filterable. The complex was stirred with heating for 48 hours till completion of reaction. The green colored complex was filtered, washed and vacuum dried.
Preparation of copper-lignosulfonate complex -B
A known amount of lignin (l0gm) was dissolved in small amount of alkaline solution and refluxed with a solution of known concentration of sodium sulphite(2.5 gm) and sodium carbonate ( 0.23 gm) in water for 48 hours. The saturated solution of copper sulphate was added in the same solution till complete precipitation occurred and stirred on a magnetic stirrer with heating for 28 hours for completion of reaction. A brownish green complex was formed which was washed thoroughly with water till free copper is removed. It was air-dried and then vaccum dried to record the yield.
Determination of copper content in complex A and B
The copper content in both the complex was determined by standard procedure as given in IS: 2753,1968 (Part II). Evaluations of complex A and B for fungi toxicity
Effectiveness of wood preservative against fungi in terms of inhibition and killing concentration was evaluated by the following method.
Two percent malt agar and different concentrations of ammonical solution .of complex A and B i.e. 0.001%, 0.003%, 0.005% and 0.007% were prepared separately. After sterilization of malt agar the medium was slanted in sterilized petriplate of 100mm diameter along with different concentration of complex A and B. Each plate contained 30ml of the medium. Three replicates were used for each concentration of complex and for control
The petriplates containing the medium was inoculated with an inoculum taken from an actively growing culture 14-16 days old of Poria monticola Murr. and Polyporous versicolor (Linn) Frr. a brown and white rot fungus respectively.
The plates were incubated for 15 days at 25±2°C temperature and relative humidity of 70±4 in the incubator (BOD), and toxicity of the complex A and B was studied. The cultures were examined and total inhibition or killing of each test fungus was noted. Permanency test of complex A and B
Permanency against/ leachability is one of the important characteristics of an ideal wood preservative. Therefore, leachability of the complex A and B was tested. Blocks of chir (Finns roxburghii) and Mango (Mangifera indica) of the size 19x19x19 mm, free from any physical defects and decay were prepared. Blocks were conditioned to constant weight, kept in a beaker under a weight to prevent floating and placed in a desiccator connected to a manometer and suction pump.
A partial vacuum is created in desiccator for 30 minutes and complex A at 0.0175% concentration was poured inside the beaker through the separating funnel, covering completely the blocks. Then the vacuum was released and blocks were allowed to remain for 30 minutes and then taken out and weighed immediately after wiping the excess of preservative. Retention, of the preservative was calculated. The treated blocks were conditioned at room temperature in a desslcator.
Six blocks impregnated with complexes placed in Erlenmeyer flask equipped with ground glass stopper, a magnetic stirrer and a plastic mesh to separate specimens. 300ml of distilled water was poured, stirred at 23±5°C and leachates were removed at 6, 24, 48 hours and replaced with deionized water and leaching was continued upto 14 days and all leachates were analysed for copper content. Leached blocks were conditioned for constant weight, grinded to dust and copper was estimated.
Testing of efficacy of Complex A and B on fungal decay of wood
The agar test was useful only as a preliminary test and for
comparing the toxicities of compounds of similar nature tests should be carried out with pure culture of the organisms, which normally attacks the material in service.
Soil block method
The test blocks of softwood i.e. Pinus roxburgii and hardwood i.e. Mangifera indica of 19x19x19 mm with a 3.2 mm central hole, from sapwood portion of wood, and feeder blocks from semul (Bombax ceiba) of 4x19x35 mm along the length of grain were prepared. Test block were treated with 0.0175, 0.0375 and 0.05 percent concentration of complex A and B as described earlier.
Preparation of soil culture bottle
Air dried garden soil amounting to 125 g with pH between 5.0 to 7.0 is filled in screw-capped bottles, 40 ml of distilled water and two feeder blocks were placed on the surface of soil and sterilized for 30 minutes. The fungus Poria monticola Murr. and Polyporons versicolor (Linn) frr. inocoulum (10 mm square of 3 week old culture) was
placed on the edge of the feeder block and incubated at 25±2°C and 70±4 percent relative humidity for approximately 3 weeks.
Test blocks, with different retentions were placed into lightly fitted container and sterilized at 100°C for 20 minutes at atmospheric pressure. After cooling the test blocks were placed with cross section face down on feeder blocks in test bottles. Bottles were placed in an incubator at 25±1°C at 70±4 percent humidity for a period of 12 weeks.
After the required test period, blocks were removed cleaned off mycelium, dried and conditioned to a content weight, percent weight loss was calculated. (IS: 4833, 1968).
Testing of efficacy of preservative against termite in mounds
Mangifera indica and Pinus roxburghii samples of size 100x25x6 mm, with a hole at 10 mm from the end were prepared conditioned and treated with 0.0175, 0.0375 and 0.05 percent concentration of complex A and B. Untreated samples served as control. Six replicates in each absorption and retention, with a conditioned weight, with each salt were buried at different places inside a termite mound of Odentotermes obesus in a randomized fashion alongwith control in the month of May and samples were removed in November when activity of termites almost ceases due to fall in temperature. Samples were removed from mound, cleaned off mud and debris and evaluated visually and through weight loss. Similarly leached samples were also evaluated for weight loss along with unleached samples.
Veneer samples (153x38x 6.25 mm) of chir and mango properly dried, conditioned were treated with complex A, B and pure lignin. Samples were treated at four concentrations 0.10, 0.15, 0.20 and 0.25 percent by pressure method to achieve different retention levels. Six replicates of each species and at each absorptions along with untreated control with conditioned weight were buried half below and half exposed above the ground in horizontal and vertical rows 60 cm apart in a split plot design. Regular
inspection is carried out every month because study is in first year. Samples of Pine are performing well at all concentrations, whereas higher concentration is giving good results in mango samples. In mango attack due to fungus is visible, no attack of termite could be visible in the samples.
Performance of complex A and B
Tablel: Amount of copper complexed, retention (kg/m3) and fixation of complex A and B in chir and mango
Reference is made to the accompanying drawings and wherein :
Fig.lA shows effective levels of complex A against P.monticola and P.versicolor using
chir and mango blocks by soil block bioassays.
Fig. IB shows effective levels of complex B against P.monticola and P.versicolor using chir and mango blocks by soil block bioassays.
Black liquor lignin from wheat straw was isolated, purified and reacted with copper sulphate to yield complex A and B. Both complex A and B have exhibited high efficacy against P. monticola and P. versicolor in Agar bioassays inhibiting fungus at 0.005% and killing 0.007% concentration. Soil block bioassays showed that complex A and B both have protected pine (Pinus roxburghii) blocks, very efficiently, against brown rot and white rot, while weight loss of treated blocks (complex A &B) of mango (Mangifera indica) was observed (wt. loss ranged- 13-21.64 %) by both the fungus, it was less than the control (60%). Termite mound bioassays exhibited very little damage due to termite in unleached samples of Pine whereas, leached samples exhibited 7-18% weight loss. Contrary to this no attack of termite could be visualized in Mango unleached and leached samples but weight lost ranged between 15.00- 63%, which was mainly due to soft rot and other fungus. Low concentration of complex A and B have protected Pine blocks very well against fungus as well as termites while mango blocks shown protection mainly against termites. Preliminary observations on accelerated field test as well show that pine blocks are efficiently protected against termite and fungus at all concentrations ranging between 0.10-0.25% levels of A & B complexes. However, blocks treated with pure lignin are prone to termite's attacks thereby indicating that lignin may not be treated as preservative as such. The mango samples in untreated, lignin treated, complex treated sets show considerable infestation by soft rot fungus at all concentrations levels. Preservative protected all wooden blocks against termites efficiently. Higher concentration of preservative is comparatively performing better in protecting maneo samples in accelerated field test.,
1. A process for the preparation of copper lignin complex A and B, wherein preparation of complex A comprises in adding a saturated solution of CuSo4 5H2O to a solution of dried lignin, stirred with heating till complete precipitation, and complex B comprises in dissolving lignin in an alkaline solution and refluxed with a solution of sodium sulphite and sodium carbonate, adding a saturated solution of copper sulphate, stirred with heating till complete precipitation of the complex.
2. A process as claimed in claim 1 wherein the solution of dried lignin comprises an alkaline solution.
3. A process for the preparation of copper lignin complexes A 85 B substantially as herein described.
|Indian Patent Application Number||963/DEL/2004|
|PG Journal Number||48/2010|
|Date of Filing||27-May-2004|
|Name of Patentee||THE DIRECTOR, FOREST RESEARCH INSTITUTE|
|Applicant Address||P.O. New Forest, Dehra Dun-24 8006,INDIA.|
|PCT International Classification Number||B27K 3/40|
|PCT International Application Number||N/A|
|PCT International Filing date|