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Antioxidant activities and phenolic compounds in Bulgarian Fumaria species

Int.J.Curr.Microbiol.App.Sci

(2014) 3(2): 296-306

Antioxidant activities and phenolic compounds in

Bulgarian Fumaria species

Ivan G. Ivanov 1*, Radka Z. Vrancheva 2, Andrey S. Marchev 3, Nadezhda T. Petkova 4, Ina

Y. Aneva 5, Panteley P. Denev 4, Vasil G. Georgiev 6, Atanas I. Pavlov 2,3 1

Department of Organic Chemistry, University of Food Technologies, 4002 Plovdiv, Bulgaria 2

Department of Analytical Chemistry, University of Food Technologies, 4002 Plovdiv, Bulgaria 3

Department of Applied Microbiology, Laboratory of Applied Biotechnologies, The Stephan Angeloff Institute of Microbiology, Bulgarian Academy of Science, 4000 Plovdiv, Bulgaria 4

Department of Organic Chemistry, University of Food Technologies, 4002 Plovdiv, Bulgaria

5

Institute of Biodiversity and Ecosystem Research at the Bulgarian Academy of

Science, 1113 Sofia, Bulgaria

6

Centre for Viticulture and Small Fruit Research, Florida A & M University,

Tallahassee 32317, USA

*Corresponding author

The genus Fumaria (Fumariaceae ) consists of 60 species widely distributed all over the world and especially in Mediterranean region ( Suau et al., 2002;

Int.J.Curr.Microbiol.App.Sci (2014)3(2): 296-306

Jaberian et al., 2013). In the Bulgarian flora, the genus is represented by ten species: Fumaria officinalis L., Fumaria thuretii Boiss., Fumaria kralikii Jord., Fumaria rostellata Knaf., Fumaria schrammii(Asch.)Velen., Fumaria parviflora Lam., Fumaria densiflora DC., Fumaria petteri Rchb., Fumaria vaillanti Loisel. and Fumaria schleicherii Soy. - Will. (Assyov et al., 2012.

Extracts of Fumaria spp. have been traditionally used for treatment of some skin diseases (rashes or conjunctivitis), rheumatism, stomach ache, abdominal cramps, fever,diarrhea, syphilis and leprosy (ener, 2002; Maiza-Benabdesselam et al., 2007). Research revealed that Fumaria extracts also possessed strong antihypertensive, diuretic,hepatoprotective and laxative effects, mainly because of the presence of isoquinoline alkaloids (Suau et al., 2002). In addition, some species, such as F. cilicica Hausskn, F. densiflora DC., F. kralikii, F. parviflora and F. vaillantii have been reported to possess significant antioxidant activities, due to their high phenolic contents (Orhan et al., 2012; Riaz et al., 2012; Jaberian et al., 2013). Antioxidants have been used as important protective agents for human health against oxidative stress disorders, as well as protectors against oxidative damage in food systems. During the last decade, there is a growing demand of natural plant extracts with antioxidant activity because of the increased report for carcinogenic effect of some synthetic antioxidants, currently applied in foods, cosmetics, and pharmacy (Riaz et al., 2012). Plant polyphenols are example for natural compounds with strong antioxidant properties (Kuli i et al., 2006). The presence of polyphenols in medicinal plants could additionally increase the added value of their extracts by enhancing their antioxidant activity or improving their overall biological activities. Therefore, characterization and evaluation of biological activities of those compounds are critical steps in assessment of herbal extracts for their possible application as food additives or pharmaceuticals. However, there was scanty information concerning polyphenol composition and antioxidant activities of Fumaria extracts and according to our best, such data is missing for Bulgarian Fumaria ssp. The aim of this study was to analyze the polyphenolic contents and antioxidant activities of extracts of five Fumaria species grown in Bulgaria: Fumaria officinalis, Fumaria thuretii, Fumaria kralikii, Fumaria rostellata and Fumaria schrammii.

Materials and Methods

Plant materials

Aerial parts (leaves, stems and flowers) by several random chosen plants of F. officinalis L., F. thuretii Boiss., F. kralikii Jord., F. rostellata Knaf. and F. schrammii (Asch.) Velen. were collected from their natural habitats in Bulgaria. F. rostellata and F. thuretii were collected from Blagoevgrad region, F. officinalis, F. kralikii and F. schrammii were collected from Black sea region, all in May 2012. Identification of the plant species was made through the reference to the Academy of Sciences Herbarium (Herbarium of the Institute of Biodiversity and Ecosystem Research in Sofia (SOM)) and with the Herbarium of Sofia University. Transect method was used for establishing the distribution of Fumaria species of the localities. Transects were selected in order to cover the maximum area. The samples were dried in shade at

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ambient temperature for 14 days, and powdered by homogenizer. The powder was used for extraction of polyphenols.

Extraction procedure

Each plant sample (0.5 g) was extracted three times with 70% ethanol at 70 oC in water bath for 15 min. The biomass was removed through filter paper filtration, and the combined ethanol extracts were used for the next analyses.

Total phenolics

The total phenolic contents were measured using a Folin-Ciocalteu assay according to the procedure described by Stintzing et al., (2005) with some modifications. Folin-Ciocalteu reagent (1mL) (Sigma) diluted five times was mixed with 0.2 mL of sample and 0.8 mL 7.5%Na2CO3 (Sigma). The reaction was 20 min at room temperature in darkness. After reaction time, the absorption of sample was recorded at 765 nm against blank sample, developed the same way but without extract. The results were expressed in mg equivalent of gallic acid (GAE) per g dry weight (DW), according to calibration curve, build in range of 0.02 - 0.10mg gallic acid (Sigma) used as a standart. Total flavonoids

Total flavonoids were determined spectrophotometrically by the method described by Kivrak et al., (2009). Each obtained extract (0.2 mL) was added to test tubes containing 0.1 mL 10% aluminum nitrate (Sigma), 0.1 mL 1M potassium acetate (Sigma) and 3.8 mL ethanol (Merck). The reaction time was 40 min at ambient temperature. The absorbance was measured at 415 nm. The results were expressed in mg equivalent of quercetin per g dry weight (DW), according to the calibration curve, linear in range of 10-100 μg/mL quercetin as a standart.

HPLC analysis

Qualitative and quantitative determinations of phenolic acids and flavonoids, were performed by using Waters 1525 Binary Pump HPLC systems (Waters, Milford, MA, USA), equipped with Waters 2484 dual Absorbance Detector (Waters, Milford, MA, USA) and Supelco Discovery HS C18 column (5 μm, 25 cm × 4.6 mm), operated under control of Breeze 3.30 software. For separation of the phenolic acids, a mobile phase of 2% (v/v) acetic acid (solvent A) and 0.5 % (v/v) acetic acid : acetonitrile (1:1, v/v) (solvent B ) was used. The gradient program used was described previously by Marchev et al., (2011). Ferulic, sinapic, p-coumaric acids (Sigma) were used for creation of standard calibration curves. For separation of flavonoids a mobile phase, consists of 2.0 % (v/v) acetic acid (solvent A) and methanol (solvent B) was used. The elution program was described by Marchev et al., (2011). Myricetin, kaempferol, quercetin, hesperidine and apigenin (Sigma) were used for calibration standard curves. The quercetin glycosides rutin and hyperoside were analyzed on the same HPLC system by using gradient of 2% (v/v) acetic acid (Sigma) (solvent A) and acetonitrile (Sigma) (solvent B). The elution program was: 0-15 min 80% A and 20% B, 15-17 min 50% A and 50% B, 17-20 min 80% A and 20% B. The detection was carried out at 370 nm.

DPPH assay

Each analyzed extract (0.15 mL) was mixed with 2.85 mL freshly prepared 0.1

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mM solution of 1,1-diphenyl-2-picrylhydrazyl radical (DPPH, Sigma) in methanol (Merck). The reaction was performed at 37 °C in darkness and the absorptions at 517 nm were recorded after 15 min against methanol. The antioxidant activity was expressed as mM Trolox equivalents (TE) per g dry weight (DW) by using calibration curve, build by 0.05, 0.1, 0.2, 0.3, 0.4 and 0.5 mM 6-hydroxy-2,5,7,8-tetramethylchroman- 2- carboxylic acid (Trolox, Fluka) dissolved in methanol (Sigma). Calculations of % inhibition and EC50 were determined as described by Kivrak et al., (2009).

ABTS assay

The method described by Thaipong et al., (2006) was used after some modifications. ABTS radical was generated by mixing aliquot parts of 7.0 mM 2, 2`azinobis (3)-ethylbenzthiazoline-6-sulfonic acid (ABTS, Sigma) in dd H2O and 2.45 mM potassium persulfate (Merck) in dd H2O. The reaction was performed for 16 h at ambient temperature in darkness and the generated ABTS radical is stable for several days. Before analyses, 2.0 mL of generated ABTS.+ solution was diluted with methanol at proportions 1:30 (v/v), so the obtained final absorbance of the working solution was about 1.0 ÷ 1.1 at 734 nm. For the assay, 2.85 mL of this ABTS.+ solution was mixed with 0.15 mL of obtained extracts. After 15 min at 37 °C in darkness the absorbance was measured at 734 nm against methanol. The antioxidant activity was expressed as mM (TE)/g DW by using calibration curve, build in range of 0.05-0.5 mM Trolox (Fluka) dissolved in methanol (Merck). Ferric reducing antioxidant power (FRAP) assay

The assay was performed according to method, described by Benzie and Strain (1996) slightly modified as follow: the FRAP reagent was freshly prepared before analyzes by mixing 10 parts 0.3 M acetate buffer (pH 3.6), 1 part 10 mM 2,4,6-tripyridyl-s-triazine (TPTZ, Fluka) in 40 mM HCl (Merck) and 1 part 20 mM FeCl3.6H2O (Merck) in dd H2O. The reaction was started by mixing 3.0 mL FRAP reagent with 0.1 mL of investigated extract. Blank sample, prepared with methanol instead of extract was developed as well. The reaction time was 10 min at 37 ° in darkness and the absorbance at 593 nm of sample against blank was recorded. Antioxidant activity was expressed as mM TE/g DW by using calibration curve, build in range of 0.05-0.5 mM Trolox (Fluka) dissolved in methanol (Merck).

Cupric reducing antioxidant capacity (CUPRAC) assay

The assay was performed according to Apak et al., (2006) with some modifications. Reaction was started by mixing 1.0 mL 10 mM CuCl2.2H2O (Sigma) in dd H2O, 1.0 mL 7.5 mM Neocuproine (Sigma) in methanol, 1.0 mL 0.1 M ammonium acetate buffer (pH 7.0), 0.1 mL of investigated extract and 1.0 mL dd H2O. Blank sample, with methanol instead of extract was developed as well. The reaction was carried out for 20 min at 50 ° in darkness and the sample absorption (450 nm) was recorded against blank. Antioxidant activity was expressed as mM (TE)/g DW by using calibration curve, build in range of 0.05-0.5 mM Trolox (Fluka) dissolved in methanol (Merck).

Statistical analyses

Plant material of each species was collected as average sample from several randomly chosen individual plants from

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the same habitat. Three independent extracts were prepared from each sample

and each extract was analyzed for polyphenol content and antioxidant activities in triple replication. The presented values are means (n = 3) with standard deviations (± SD). Figures were made by Microsoft Office Excel ? 2000. Results and Discussion

Analyses of total phenolics and total flavonoids

Fumaria species were traditionally used against liver diseases in folklore medicine

of many countries Orhan et al., (2012). Study on hepatoprotective activity of different fractions of ethanol extract from

F. indica (Hausskn.) Pugsley. showed that mainly the alkaloid protopine is responsible for the observed high liver protection effects of this plant (Rathi et al., 2008). Growing demand of natural herbs

for application in medicine leads to approval of F. officinalis for application in treatment of colick pains in Germany (Hentschel et al., 1995). However, for deep understanding and correct evaluation

of pharmaceutical values, more detailed investigations on composition and biological activities of extracts from different Fumaria species should be performed. In this study we investigated phenolic and flavonoid contents and antioxidant activities of five Fumaria species (F. officinalis, F. thuretii, F. kralikii, F. rostellata and F. schrammii), growing in Bulgaria. All investigated plants showed high total phenolic contents, ranging between 20.20 ± 0.29 (in

F. thuretii) and 30.30 ± 0.31 mg GAE/g

DW (in F. officinalis) (Figure 1). As comparison, recent published data showed

that total phenolic contents of ethanol extracts from F. cilicica, F. densiflora, F. kralikii and F. parviflora collected in Turkey varied in significantly lower range (between 0.05 and 0.09 mg GAE/g dry extract or approximately 0.015 and 0.030 mg GAE/g DW) (Orhan et al., 2012). Similar tendency could be observed also in the total flavonoid contents. In our study the concentration of total flavonoids in ethanol extracts of F. officinalis, F. thuretii, F. kralikii, F. rostellata and F. schrammii ranged between 8.70 ± 0.01 to 16.62 ± 0.03 mg QE/g DW (Figure 1), whereas Orhan et al., (2012) reported total flavonoid contents in ethanol extract of Turkish F. cilicica, F. densiflora, F. kralikii and F. parviflora to varied between 0.02-0.05 mg QE/g dry extract (or approximately 0.0060.017 mg QE/g DW). The observed differences in results, reported by Orhan et al., (2012) and the data in the current study are most probably due to the different extraction methods applied, instead of geographical and climate differences at which plants were grown. Recently, Jaberian et al., (2013) reported that methanol extract of F. vaillantii contains more total phenolics, compared to methanol-water extract (10.5 compared to 4.27 mg GAE/g DW), whereas the methanol-water extract was rich in total flavonoids (3.11 compared to 2.07 mg QE/g DW in methanol extract). The reported values of F. vaillantii extracts by Jaberian et al., (2013) were in the same range as the data we reported in this study. However, it is obviously that Bulgarian F. officinalis, F. thuretii, F. kralikii, F. rostellata and F. schrammii have higher phenolic and flavonoid contents, compared to F. vaillantii. HPLC analyses of polyphenols

To obtain more detailed data about phenolic profile of ethanol extracts from investigated five Fumaria species, we

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analyzed the contents of major flavonoids and phenolic acids in them (Table 1). Three flavonols (myricetin, kaempferol and quercetin), two quercetin glycosides (rutin and hyperoside), one flavanone (hesperidin), one flavone (apigenin) and three phenolic acids (p-coumaric, ferulic and sinapic acids) were identified and quantified (Table 1).

HPLC analysis showed, that the observed variations in flavonoids compositions were more significant between investigated species (Table 1). Ethanol extract of F. officinalis was the richest source of quercetin (0.49 ± 0.03 mg/g DW), p-coumaric and ferulic acids (1.10 ± 0.03 and 2.35 ± 0.04 mg/g DW, respectively). High concentration of quercetin (0.51 ± 0.03 mg/g DW) was also found in extract of F. thuretii, but this was the only extract in which quercetin glycosides rutin and hyperoside were not detected. The extract of F. kralikii showed the highest levels of myricetin (0.49 ± 0.07 mg/g DW), kaempferol (0.14 ± 0.01 mg/g DW), hyperoside (7.58 ± 0.13 mg/g DW), apigenin (0.38 ± 0.03 mg/g DW, whereas the extracts of F. rostellata and F. schrammii showed the highest content of rutin (9.92 ± 0.11 and 8.39 ± 0.15 mg/g DW, respectively).

Flavanone glycoside hesperidin was not detected in extracts of F. officinalis, F. kralikii and F. rostellata. Flavone apigenin was missing only in extract of F. schrammii, whereas no quercetin glycosides (rutin and hyperoside) were detected in extract of F. thuretii (Table 1). In contrast, rutin and hyperoside were the major flavonoids in other four investigated species. This fact is of great importance, because these quercetin glycosides possessed several biological activities. Rutin was reported to have cardioprotective and hepatoprotective action (Panchal et al., 2011). This quercetin glycoside suppresses hyperglycemia, increases plasma concentrations of insulin and decreases oxidative stress (Ahmed et al., 2010, Panchal et al., 2011). Other activities such as antibacterial, antitumour, antiinflammatory, antidiarrhoeal, antiulcer, antimutagenic, myocardial protecting, vasodilator and immunomodulatory have been also reported (Janbaz et al., 2002; Pereira et al., 2008). Hyperoside possess antiviral activity, antinociceptive, antiinflammatory, cardioprotective, hepatoprotective, gastricmucosal-protective and neuroprotective effects (Liu et al., 2005; Lin-lin et al., 2007; Zeng et al., 2011).

The high content of rutin and hyperoside found in investigated Fumaria ssp. defines them as valuable sources of non-alkaloid pharmacologically active compounds.

The phenolic acids patterns in all investigated plants were similar, with slight variations in concentrations (Table 1). The high content of phenolic acids could be considered as prerequisite for expected high antioxidant activities. In addition, it is well known that phenolic acids have some important biological activities. Sinapic acid was reported to have antiinflammatory effect by suppressing production of some proinflammatory mediators (Yun et al., 2008) and p-coumaric acid could be used in fighting diseases, related to oxidative stress by protecting DNA from oxidative damages (Guglielmi et al., 2003). Evaluation of antioxidant activities

To evaluate antioxidant activities of investigated ethanol extracts, their abilities to scavenge DPPH and ABTS radicals, as well as their power to reduce ferric

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Figure.1 Total phenolics (A) and total flavonoids (B) contents in ethanol extracts

of five Bulgarian Fumaria species.

A.

B.

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Table.1 HPLC analysis of polyphenols content in ethanol extracts of five Bulgarian

Fumaria Species

Compound* F.officinalis F. thuretii F.kralikii F.rostellata F.shrammii Flavonoids

Myricetin

0.25 ± 0.01 0.28 ±

0.01

0.49 ±

0.07

0.17 ± 0.03 0.25 ± 0.01

Kaempferol

0.08 ± 0.01 0.12 ±

0.01

0.14 ±

0.01

0.06 ± 0.01 0.04 ± 0.01

Flavonols

Quercetin 0.49 ± 0.03

0.51 ±

0.03

0.36 ±

0.02

0.32 ± 0.02 0.14 ± 0.01

Rutin

6.47 ± 0.13 nd 4.17 ±

0.07

9.92 ± 0.11 8.39 ± 0.15

Quercetin glycoside

Hyperoside

6.51 ± 0.12 nd

7.58 ±

0.13

1.06 ± 0.03

2.78 ± 0.05

Flavanone glycoside Hesperidin

nd

0.29 ±

0.01

nd nd 0.26 ± 0.01

Flavone Apigenin

0.12 ± 0.02 0.17 ±

0.02

0.38 ±

0.03

0.05 ± 0.01 nd

Phenolic acids

p-Coumaric acid 1.10 ± 0.03

0.39 ±

0.05

0.50 ±

0.05

0.55 ± 0.05 0.37 ± 0.04

Ferulic acid

2.35 ± 0.04 1.74 ±

0.03

1.75 ±

0.03

2.25 ± 0.03 2.00 ± 0.04

Sinapic acid

0.68 ± 0.02 1.05 ±

0.04

3.03 ±

0.05

0.70 ± 0.02 0.38 ± 0.02

*- mg/g DW; nd not detected

Table.2 Antioxidant activities of ethanol extracts from five Bulgarian Fumaria species and

some standard phenolic compounds

Plant

extracts

DPPH */** ABTS * FRAP * CUPRAC * F. officinalis160.05 ± 3.27 / 2.39 ± 0.04131.14 ± 6.08 161.48 ± 2.67 625.67 ± 7.44 F. thuretii82.58 ± 2.91 / 5.15 ± 0.16 100.54 ± 8.87 80.63 ± 3.51 344.55 ± 1.17

F. kralikii

100.23 ± 2.07 / 4.08 ± 0.02

118.51 ±

5.11 108.59 ± 8.55 407.44 ± 7.82

F. rostellata 110.62 ± 2.41 / 3.81 ± 0.03108.30 ± 8.74 100.31 ± 7.94 395.09 ± 8.19 F. schrammii 119.41 ± 4.80 / 3.44 ± 0.09113.41 ± 5.46 120.36 ± 2.00 474.67 ± 1.77 Standards***

Quercetin 3.22 ± 0.12 / 0.19 ± 0.03 7.44 ± 3.42 6.54 ± 0.73 10.64 ± 0.34 Rutin 4.53 ± 0.13 / 0.34 ± 0.01 2.95 ± 0.2 7.91 ± 0.96 13.93 ± 0.30 Ferulic acid 4.23 ± 0.38 / 0.68 ± 0.03 8.36 ± 1.62 9.47 ± 1.44 10.05 ± 0.22 Sinapic acid 4.60 ± 0.45 / 0.53 ± 0.04 6.55 ± 0.39 10.61 ± 1.48 14.74 ± 0.38

p-Coumaric

acid 0.77 ± 0.27 / 1.14 ± 0.07 8.21 ± 1.99 5.14 ± 1.31 12.45 ± 1.98

*- values are in mM TE/g DW; **- EC50, mg DW/ml; ***- values are in mM TE/mg

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(FRAP) and cupric (CUPRAC) ions were investigated (Table 2). Ethanol extract of F. officinalis was the extract with the highest antioxidant activity in all used assays (160.05 ± 3.27, 131.14 ± 6.08, 161 ± 2.67 and 625.67 ± 7.44 mM TE/g DW for DPPH, ABTS, FRAP and CUPRAC methods, respectively), whereas the extract of F. thuretii was the extract with the lowest activity (82.58 ± 2.91, 100.54 ± 8.87, 80.63 ± 3.51 and 344.55 ± 1.17 mM TE/g DW for DPPH, ABTS, FRAP and CUPRAC methods, respectively), Table 2. Ethanol extracts of the other three investigated species (F. kralikii, F. rostellata and F. schrammii) had similar antioxidant activities (Table 2). Antioxidant activities of the major phenolic acids and some of flavonoids, detected in Fumaria extracts were determined as well (Table 2). Antioxidant activities of plant extracts were usually explained with the presence of phenolic acids and flavonoids in them (Jaberian et al., 2013). There was scanty data concerning antioxidant activities of Fumaria extracts in scientific literature. Jaberian et al., (2013) reported strong antioxidant activities of methanol and methanol-water extracts of F. vaillantii, determined by DPPH method (EC50 = 0.1273 and 0.1533 μg/mL extract, respectively). In opposite, Orhan et al., (2012) reported that ethanol extracts of F. cilicica, F. densiflora, F. kralikii and F. parviflora collected in Turkey, showed extremely low antioxidant activities in both DPPH and FRAP methods. In our study, we decided to evaluate antioxidant activities of ethanol extracts of F. officinalis, F. thuretii, F. kralikii, F. rostellata and F. schrammii by applying two methods, based on mixed hydrogen atom transfer (HAT) and single electron transfer (SET) mechanisms (DPPH and ABTS) and two methods, based only on SET mechanism (FRAP and CUPRAC). The results showed the existence of correlation between total phenolic and total flavonoid concentrations in investigated extracts ant their antioxidant activities (Figure 1 and Table 2). Thus, the ethanol extract of F. officinalis had the highest antioxidant activities and the highest total phenolic and flavonoid contents (30.30 ± 0.31 mg GAE/g DW and 15.01 ± 0.01 mg QE/g DW), whereas the extract of F. thuretii had the lowest antioxidant activities and the lower total phenolic and flavonoid contents (20.20 ± 0.29 mg GAE/g DW and 8.70 ± 0.01 mg QE/g DW) (Figure 1 and Table 2). It should be noted that the extract of F. thuretii was the only one in which rutin was not detected. Analysis of antioxidant activities of individual flavonoids and phenolic acids showed that rutin, sinapic and ferulic acids were the most active compounds (Table 2). Moreover, our data showed that the extracts with the lowest antioxidant activities (F. thuretii and F. rostellata) were the extracts without and with the lowest quercetin glycosides contents, respectively (Tables 1 and 2). Relatively high concentrations of rutin, hyperoside, sinapic and ferulic acids in extracts of F. officinalis, F. kralikii, and F. schrammii were the most probable reason for observed high antioxidant activities in those plants, compared to extract of F. thuretii.

This study demonstrates for the first time the potential of Fumaria species (F. officinalis, F. thuretii, F. kralikii, F. rostellata and F. schrammii), grown in Bulgaria, as perspective source of valuable flavonoid compounds with high antioxidant activities and health beneficial properties. Our data reveals new possibilities to expand applications of

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Fumaria extracts from a local ethnomedicine drug to new industrial fields such as foods and cosmetics preservation. The specific metabolite profiles and the remarkable antioxidant activities defined F. officinalis, F. thuretii, F. kralikii, F. rostellata and F. schrammii as interesting objects for development of in vitro systems for production of valuable flavonoids with antioxidant activities. Acknowledgement

The authors thank for the financial support of this research by the Bulgarian Science Foundation, Bulgarian Ministry of Education and Science under contract number: DMU 03/77 - 2011.

Conflicts of Interest

The authors declare no conflicts of interest.

References

Ahmed, O.M., Moneim, A.A., Yazid, I.A.

and Mahmoud, A.M. 2010.

Anthyperglycemic, antihyperlipidemic and antioxidant effects and the probable mechanisms of action of Ruta graveolens infusion and rutin in nicotinamide-streptozotocin- induced diabetic rats. Diabetol Croat. 39 (1): 15-

35.

Apak, R., Gü?lu, K., ?zyürec, M., Karademir, S.E. and Er?ag, E. 2006. The cupric ion reducing antioxidant capacity and polyphenolic content of some herbal teas. Int J Food Sci Nutr. 57 (5-6):292-

304.

Assyov, B.; Petrova, A.; Dimitrov, D. and Vassilev, R. 2012. Conspectus of the Bulgarian Vascular flora, distribution maps and floristic elements, 4th ed;

Assyov, B., Petrova, A., Eds.; Bulgarian Biodiversity Foundation: Sofia, Bulgaria, pp. 199200.Benzie, I.F. and Strain, J.J. 1996. The ferric reducing ability of plasma (FRAP) as a measure of antioxidant power: Tthe FRAP assay. Anal Biochem. 239 (1): 70-76.

Guglielmi, F., Luceri, C., Giovannelli, L., Dolara, P. and Lodovici, M. 2003. Effect of 4-coumaric and 3,4-dihydroxybenzoic acid on oxidative DNA damage in rat colonic mucosa. Br J Nutr. 89 (5): 581- 587.

Jaberian, H., Piri, K. and Nazari, J. 2013.

Phytochemical composition and in vitro antimicrobial and antioxidant activities of some medicinal plants. Food Chem.

136 (1): 237-244.

Janbaz, K.H., Saeed, S.A. and Gilani, A.H.

2002. Protective effect of rutin on paracetamol- and CCl4-induced hepatotoxicity in rodents. Fitoterapia. 73 (7-8): 557563.

Hentschel, C, Dressler, S. and Hahn, E.G.

1995. Fumaria officinalis(fumitory)

clinical applications. Fortschr der Med.

113 (19): 291-292.

Kivrak, I., Duru, M.E., ?ztürk, M., Mercan, N., Harmandar, M. and Top?u, G. 2009.

Antioxidant, anticholinesterase and antimicrobial constituents from the essential oil and ethanol extract of Salvia potentillifolia. Food Chem. 116

(2): 470-479.

Kuli i, T., Dragovi-Uzelac, V. and Milo, M. 2006. Antioxidant activity of aqueous tea infusions prepared from oregano, thyme and wild thyme. Food Technol Biotechnol. 44 (4): 485-492. Lin-lin, W.U., Yang, X., Hyang, Z., Liu, H.

and Guang-sia, W.U. 2007. In vivo and in vitro antiviral activity of hyperoside extracted from Abelmoschus manihot (L) medic. Acta Pharmacol Sin. 28 (3): 404-409.

Liu, Z., Tao, Z., Zhang, C., Lu, Y. and Wei,

D. (2005). Protective effects of

hyperoside (quercetin-3-O-galactoside) to PC12 cells against cytotoxicity induced by hydrogen peroxide and tert-butyl hydroperoxide. Biomed

Int.J.Curr.Microbiol.App.Sci (2014)3(2): 296-306

Pharmacother. 59 (9): 481-490.

Maiza-Benabdesselam, F., Khentache, S., Bougoffa, K., Chibane, M., Adach, S., Chapeleur, Y., Max, H. and Laurain-

Mattar, D. 2007. Antioxidant activities of alkaloid extracts of two Algerian species of Fumaria: Fumaria capreolata and Fumaria bastardi. Rec Nat Prod. 1 (2-3): 28-35.

Marchev, A., Georgiev, V., Ivanov, I., Badjakov, I. and Pavlov, A. 2011. Two-

phase temporary immersion system for Agrobacterium rhizogenes genetic transformation of sage (Salvia tomentosa Mill.). Biotechnol Lett. 33

(9): 1873-1878.

Orhan, I.E., Sener, B. and Musharraf, S.G.

2012. Antioxidant and hepetoprotective activity appraisal of four selected Fumaria species and their total phenol and flavonoid quantities, Exp Toxicol Pathol. 64 (3): 205-209.

Panchal, S.K., Poudyal, H., Arumugam, T.V. and Brown, L. 2011. Rutin attenuates metabolic changes, nonalcoholic steatohepatitis, and cardiovascular remodeling in high carbohydrate, high-fat diet-fed rats. J Nutr. 141 (6): 1062-1069.

Pereira, A.C., Oliveira, D.F., Silva, G.H., Figueiredo, H.C., Cavalheiro, A.J., Carvalho, D.A., Souza, L.P. and Chalfoun, S.M. 2008. Identification of the antimicrobial substances produced by Solanum palinacanthum

(Solanaceae). An Acad Bras Cienc. 80

(3): 427-432.

Rathi, A., Srivastava, A.K., Shirwaikar, A., Singh Rawat, A.K. and Mehrotra, S.

2008. Hepatoprotective potential of Fumaria indica Pugsley whole plant extracts, fractions and an isolated alkaloid protopine. Phytomedicine. 15 (6-7): 470-477.

Riaz, T., Abbasi, M.A., Rehman, A., Shahzadi, T. and Ajaib, M. 2012.

Fumaria indica: A valuable natural source of antioxidants for protection against oxidative stress. JPSI.1 (1): 16-

21.

Sener, B. 2002. Molecular diversity in the alkaloids of Turkish Fumaria L. species.

Acta Pharm Turc. 44, 205-212. Stintzing, F.C., Nerbach, K.M., Mosshammer, M., Carle, R., Yi, W., Sellappan, S., Acoh, C.C., Bunch, R.

and Felker, P. 2005. Color, betalain pattern, and antioxidant properties of cactus pear (Opuntia spp.) clones. J Agric Food Chem. 53 (2): 442-451. Suau, R., Cabezudo, B., Rico, R., Najera, F.

and Lopez-Romero, J.M. 2002. Direct determination of alkaloid contents in Fumaria species by GC-MS. Phytochem Anal. 13 (6): 363-367.

Thaipong, K., Boonprakob, U., Crosby, K., Cisneros-Zevallos, L. and Byrne, D.

2006. Comparison of ABTS, DPPH, FRAP, and ORAC assays for estimating antioxidant activity from guava fruit extracts. J Food Compos Anal. 19, 669-675.

Yun, K., Koh, D., Kim, S., Park, S.J., Ryu, J.H., Kim, D., Lee, J. and Lee, K. 2008.

Anti-inflammatory effects of sinapic acid through the suppression of inducible nitric oxide synthase, cyclooxygase-2, and proinflammatory cytokines expressions via nuclear factor-kB inactivation. J Agric Food Chem. 56

(21): 10265-10272.

Zeng, K.W., Wang, X.M., Ko, H., Kwon,

H.C., Cha, J.W. and Yang, H.O. 2011.

Hyperoside protects primary rat cortical neurons from neurotoxicity induced by amyloid -protein via the PI3K/Akt/Bad/Bcl X-regulated mitochondrial apoptotic pathway. Eur J Pharmacol. 672 (1-3), 45-55.

聚氨酯新材料项目职业病危害检测评价分析

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石墨电极的原料及制造工艺

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浇注型聚氨酯..

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抗氧化剂思考题

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石墨电极在黄磷冶炼中的应用 近年来我国的黄磷企业迅速扩增,其产品不仅遍及全国各地,而且已形成了大量出口的趋势。黄磷冶炼行业的崛起,为炭素厂家又增加了一大市场。仅我国西南地区年产黄磷制品就近百万吨,年耗石墨电极约3万t。因此,石墨电极如何适用于电炉冶炼黄磷的技术课题,已经提到电极生产厂家的面前。人造石墨电极具有良好的导电、导热、耐高温氧化、耐腐蚀性能,是黄磷冶炼炉理想的导电电极。石墨电极的生产工艺过程,一般是将石油焦、沥青焦等炭质原料经煅烧后,再加粘结剂沥青进行混捏、凉料后经挤压成型而形成生制品,生制品再经过1 300 ℃焙烧后成为半成品,半成品再经过2 300 ℃石墨化、机械加工而得到石墨电极成品。目前,炭素企业生产的石墨电极,其部分规格的理化指标列于表1。表1 石墨电极的主要理化指标 规格/mm 品种电阻率/μΩ.m 体积密度/kg/cm3 抗折强度/MPa 弹性模量/GPa 热膨胀系数/×10-6/℃灰分/% 本体接头本体接头本体接头本体接头本体接头 600 UHP 6.5 4.5 1.66 1.75 10.0 18.0 14.0 22.0 1.40 1.20 0.5 500 HP 7.0 6.5 1.60 1.70 9.8 14.0 12.0 14.0 2.20 2.40 0.3 500UHP NP 9.0 8.5 1.52 1.68 6.4 12.7 9.3 13.7 2.90 3.20 0.5 1 黄磷冶炼与石墨电极的消耗 工业上依黄磷冶炼中的热源不同,黄磷冶炼方法可分为电炉法和高炉法。目前我国的黄磷冶炼工业主要以电炉法为主,这种冶炼方法实收率高,产品纯度高。电炉法生产是将磷矿石、硅石和焦炭的混合料加入电炉内,由通过炉盖的石墨电极(作为导电极)将电能转变成热能,从而把混合料加热至熔融状态,使元素磷升华后再将含磷气体进行冷凝、分离和精制而得到元素磷。黄磷冶炼的工艺过程如图1。

抗氧剂协同作用机理

抗氧剂的协同作用 聚合物稳定化助剂种类繁多,功能各异。但大量研究结果表明,不同类型,甚至同一类型、不同品种的抗氧剂之间都有可能存在协同或对抗作用。汽巴精化(Ciba—Geigy)公司开发的Irganox B系列复合型抗氧剂的研究表明,抗氧剂之间复配得当,不仅可以提高产品性能,增强抗氧效果,还可降低成本;但如果搭配不当,不但起不到抗氧作用,可能还会加速聚合物的老化。受阻酚类抗氧剂以其抗氧效果好、热稳定性高、低毒等诸多优点近年来倍受人们关注。但抗氧剂复配是否得当直接影响抗氧效果的好坏。因此,研究抗氧剂复配时的作用机理显得尤为重要。近年来,世界各大抗氧剂的生产厂商都在致力于研究开发复合型抗氧剂,而熟知各种抗氧剂之间的协同作用机理对抗氧剂新品种开发具有重要的指导 意义 1 受阻酚类抗氧剂的作用机理 聚合物材料在高温加工或使用过程中,由于氧原子的袭击会使其发生氧化降解。经过多年的研究发现,聚合物的A动氧化过程是一系列A由基反应过程。反应初期的主要产物是由氢过氧化物在适当条件下分解成活性自由基,该自由基又与大分子烃或氧反应生成新的自由基,这样周而复始地循环,使氧化反应按自由基链式历程进行。 在聚合物中添加抗氧剂,就是为了捕捉链反应阶段形成的自由基R.和R00 .,使它们不致引起有破坏作用的链式反应;抗氧剂还能够分解氢过氧化物RO0H,使其生成稳定的非活性产物。按作用机理,抗氧剂可分为主抗氧剂和辅助抗氧剂。主抗氧剂能够与自由基R.,ROO .反应,中断活性链的增长。辅助抗氧剂能够抑制、延缓引发过程中自由基的生成,分解氢过氧化物,钝化残存于聚合物中的金属离子[1]。 作为主抗氧剂的受阻酚类抗氧剂是一类在苯环上羟基(~OH)的一侧或两侧有取代基的化合物。由于一OH受到空间障碍,H原子容易从分子上脱落下来,与过氧化自由基(ROO .)、烷氧自由基(RO.)、羟自由基(.OH)等结合使之失去活性,从而使热氧老化的链反应终止,这种机理即为链终止供体机理[2]。 在聚合物老化过程中,如果可以有效地捕获过氧化自由基,就可以终止该氧化过程。但生成过氧化自由基的反应速率极快,所以在有氧气存在的条件下,自由基捕获剂便会失效。在受阻酚类抗氧剂存在的情况下,1个过氧化自由基(R00 7)将从聚合物(RH)上夺取1个质子,打断这一系列自由基反应,这是自动氧化的控制步骤。当加入受阻酚抗氧剂时,它比那些聚合物更易提供质子,即提供了一个更加有利的反应形成酚氧自由基,这使聚合物相对稳定,不会进一步发生氧化。 除此之外,受阻酚还可以进行一些捕捉碳自由基的反应。如上式的2,4,6一自由基可以生成二聚物,而这种二聚物又可与过氧化自由基反应使其失去活性,自身则变成稳定的醌分子[2]。由于每个受阻酚可以捕捉至少2个自由基,故其抗老化的效果较好。

新型聚氨酯固化剂的研究与发展

新型聚氨酯固化剂的研究与发展 张修景(菏泽学院化学与化工系,山东菏泽274015) 摘要:阐述了颜色低于铁钴比色计1号,游离TDI含量小于0.5%,贮存稳定性达2年以上的新型聚氨酯固化剂的生产工艺;确定了含羟基丙烯酸树脂与该固化剂的质量比为:m(含羟基丙烯酸树脂)∶m(新型聚氨酯固化剂)=10∶4~6;分析了碱性物质是导致聚氨酯固化剂成胶的原因;提出了保证聚氨酯固化剂低色值、低游离TDI含量和高贮存稳定性的方法。 关键词:新型聚氨酯固化剂;色值;游离TDI含量;稳定性 0.引言 国内科研单位及相关企业、院校对于聚氨酯固化剂的研究做了大量工作,朱吕民[1]介绍了色泽为8号(铁钴比色计)TDI加成物的制法;彭红为,等[2-3]报道的产品的游离TDI含量高达3.0%~5.0%,配制的涂料在施工过程中对人体伤害很大,环境污染严重,不仅远远高出世界卫生组织游离TDI含量≤0.5%的要求,而且很难达到我国《室内装饰装修材料溶剂型木器涂料中有害物质限量》GB18581—2001强制标准中≤0.7%的规定。国外通常采用薄膜蒸发法,如Bayer公司采用该技术产品的游离TDI含量<0.5%。国内相关研究[4-10]对于降低游离TDI做了大量积极工作,并提出了在聚氨酯生产中推行清洁生产的建议和措施,但实现工业化生产的报道很少。赵文斌,等[10]的产品通过热重分析(TG)显示,改性TDI三聚体的热稳定性有一定下降。为此,本文研究了颜色低于铁钴比色计1号,游离TDI<0.5%,贮存稳定性达2年以上的TDI-TMP加成物,找到了该固化剂与含羟基丙烯酸树脂的最佳配比,可赋于漆膜多种优良的性能。 1.实验部分 1.1原料 甲苯二异氰酸酯(TDI):80/20,国产;三羟甲基丙烷(TMP):美国产;乙酸丁酯:工业一级品,无水;二月桂酸二丁基锡、缩二脲:工业一级品;磷酸(85%)、三正丁基膦、对硝基苯甲酰氯:分析纯;氮气(99199%)。 1.2反应原理 TDI-TMP加成物主要是指3分子的甲苯二异氰酸酯(TDI)与1分子的三羟甲基丙烷(TMP)的加成物,反应如式1。 1.3方法 新型聚氨酯固化剂的中试配方见表1。

常用抗氧化剂性能

常用抗氧剂的性能与用途 最近看资料学习中看到了不少的好东西跟大家一起分享下,希望以后有资料大家相互交流交流 1、抗氧剂1010。白色流动性粉末,熔点120~125℃,毒性较低,是一种较好的抗氧剂。他在聚丙烯树脂中应用较多,是一种热稳定性高、非常适合于高温条件下使用的助剂,能延长制品的使用寿命,另外,也可以用于其它大多数树脂。一般加入量不大于0.5% 2、抗氧剂1076。白色或微黄结晶粉末,熔点为50~55℃,无毒,不溶于水,可溶于苯、丙酮、乙烷和酯类等溶剂。可作为聚乙烯、聚丙烯、聚苯乙烯、聚氯乙烯、聚酰胺、ABS和丙烯酸等树脂的抗氧剂。具有抗氧性好、挥发性小、耐洗涤等特性。一般用量不大于0.5%;可用作食品包装材料成型用助剂。 3、抗氧剂CA。白色结晶粉末,熔点180~188℃,毒性低,溶于丙酮、乙醇、甲苯和醋酸乙酯。适合于聚丙烯、聚乙烯、聚氯乙烯、ABS和聚酰胺树脂中的抗氧助剂,并可用于与同接触的电线、电缆。一般用量不超过0.5% 4、抗氧剂164。白色或浅黄色结晶粉末或片状物。熔点在70℃,沸点在260℃左右、无毒。用于多种树脂中,用途广泛。更适合用于食品包装成型用料(聚丙烯、聚乙烯、聚氯乙烯、ABS、聚酯和聚苯乙烯)树脂中,一般用量为0.01%~0.5% 5、抗氧剂DNP。浅灰色粉末,熔点230℃左右,易溶于苯胺和硝基苯中,不溶于水。适合于聚乙烯、聚丙烯。抗冲击聚苯乙烯和ABS树脂,除具有抗氧效能外,还有较好的热稳定作用和抑制铜、檬金属的影响。一般用量应不超过2% 6、抗氧剂DLTP。白色结晶粉末,熔点在40℃左右,毒性低,不溶于水,能溶于苯、四氯化碳、丙酮。用于聚乙烯、聚丙烯、ABS和聚氯乙烯树脂的辅助抗氧剂,可改变制品的耐热性和抗氧性。一般用量为0.05%~1.5% 7、抗氧剂TNP。浅黄色粘稠液体,凝固点低于-5℃沸点大于105℃,无味,无毒,不溶于水,溶于丙酮、乙醇,。苯和四氯化碳。适合于聚氯乙烯、聚乙烯、聚丙烯、抗冲击聚苯乙烯和ABS、聚酯等树脂,高温中抗氧化性能高,使用量不超过1.5%。 8、抗氧剂TPP。浅黄色透明液体,凝固点19~24℃,沸点220℃,溶于醇、苯、丙酮。适合于聚氯乙烯、聚苯乙烯、聚丙烯和ABS树脂的辅助抗氧剂,使用量应不超过3%。 9、抗氧剂MB。淡黄色粉末,熔点大于285℃,溶于乙醇、丙酮、醋酸乙酯,不溶于水和苯,适合于聚乙烯、聚酰胺和聚丙烯树脂的抗氧剂;本品不污染,不着色,可用于白色或艳色制品。用量不超过0.5%。

石墨电极

石墨电极 石墨电极(graphite electrode) 以石油焦、沥青焦为颗粒料,煤沥青为黏结剂,经过}昆捏、成型、焙烧、石墨化和机械加工而制成的一种耐高温的石墨质导电材料。石墨电极是电炉炼钢的重要高温导电材料,通过石墨电极向电炉输入电能,利用电极端部和炉料之间引发电弧产生的高温为热源,使炉料熔化进行炼钢,其他一些电冶炼或电解设备也常使用石墨电极为导电材料。2000年全世界消耗石墨电极100万t左右,中国2000年消耗石墨电极25万t左右。利用石墨电极优良的物理化学性能,在其他工业部门中也有广泛的用途,以生产石墨电极为主要品种的炭素制品工业已经成为当代原材料工业的重要组成部门。 简史早在1810年汉佛莱?戴维(Humphry Davy)利用木炭制成通电后能产生电弧的炭质电极,开辟了使用炭素材料作为高温导电电极的广阔前景,1846年斯泰特(Stair)和爱德华(Edwards)用焦炭粉及蔗糖混合后加压成型,并在高温下焙烧从而制造出另一种炭质电极,再将这种炭质电极浸在浓糖水中以提高其体积密度,他们获得了生产这种电极的专利权。1877年美国克利夫兰(Cleveland)的勃洛希(C.F.Brush)和劳伦斯(https://www.doczj.com/doc/2517888500.html,wrence)采用煅烧过的石油焦研制低灰分的炭质电极获得成功。1899年普利查德(O.G.Pritchard)首先报道了用锡兰天然石墨为原料制造天然石墨电极的方法。1896年卡斯特纳(H.Y.Gastner)获得了使用电力将炭质电极直接通电加热到高温,而生产出比天然石墨电极使用性能更好的人造石墨电极的专利权。1897年美国金刚砂公司(Carborundum Co.)的艾奇逊(E.G.Acheson)在生产金刚砂的电阻炉中制造了第一批以石油焦为原料的人造石墨电极,产品规格为22mm×32m mX380mm,这种人造石墨电极当时用于电化学工业生产烧碱,在此基础上设计的“艾奇逊”石墨化炉将由石油焦生产的炭质电极及少量电阻料(冶

石墨电极的生产工艺流程和质量指标的及消耗原理知识讲解

石墨电极的生产工艺流程和质量指标的及 消耗原理

目录 一、石墨电极的原料及制造工艺 二、石墨电极的质量指标 三、电炉炼钢简介及石墨电极的消耗机理 石墨电极的原料及制造工艺 ●石墨电极是采用石油焦、针状焦为骨料,煤沥青为粘结剂,经过混 捏、成型、焙烧、浸渍、石墨化、机械加工等一系列工艺过程生产出来的一种耐高温石墨质导电材料。石墨电极是电炉炼钢的重要高温导电材料,通过石墨电极向电炉输入电能,利用电极端部和炉料之间引发电弧产生的高温作为热源,使炉料熔化进行炼钢。其他一些冶炼黄磷、工业硅、磨料等材料的矿热炉也用石墨电极作为导电材料。利用石墨电极优良而特殊的物理化学性能,在其他工业部门也有广泛的用途。生产石墨电极的原料有石油焦、针状焦和煤沥青 ●石油焦是石油渣油、石油沥青经焦化后得到的可燃固体产物。色黑 多孔,主要元素为碳,灰分含量很低,一般在0.5%以下。石油焦属于 易石墨化炭一类,石油焦在化工、冶金等行业中有广泛的用途,是生产人造石墨制品及电解铝用炭素制品的主要原料。 ●石油焦按热处理温度区分可分为生焦和煅烧焦两种,前者由延迟 焦化所得的石油焦,含有大量的挥发分,机械强度低,煅烧焦是生焦经煅烧而得。中国多数炼油厂只生产生焦,煅烧作业多在炭素厂内进行。 ●石油焦按硫分的高低区分,可分为高硫焦(含硫1.5%以上)、中 硫焦(含硫0.5%-1.5%)、和低硫焦(含硫0.5%以下)三种,石墨电极及其它人造石墨制品生产一般使用低硫焦生产。 ●针状焦是外观具有明显纤维状纹理、热膨胀系数特别低和很容易石 墨化的一种优质焦炭,焦块破裂时能按纹理分裂成细长条状颗粒(长宽比一般在1.75以上),在偏光显微镜下可观察到各向异性的纤维状结 构,因而称之为针状焦。 ●针状焦物理机械性质的各向异性十分明显, 平行于颗粒长轴方向具 有良好的导电导热性能,热膨胀系数较低,在挤压成型时,大部分颗粒的长轴按挤出方向排列。因此,针状焦是制造高功率或超高功率石墨电极的关键原料,制成的石墨电极电阻率较低,热膨胀系数小,抗热震性能好。 ●针状焦分为以石油渣油为原料生产的油系针状焦和以精制煤沥青 原料生产的煤系针状焦。 ●煤沥青是煤焦油深加工的主要产品之一。为多种碳氢化合物的混合 物,常温下为黑色高粘度半固体或固体,无固定的熔点,受热后软化,继而熔化,密度为1.25-1.35g/cm3。按其软化点高低分为低温、中温和高温沥青三种。中温沥青产率为煤焦油的54-56%。煤沥青的组成极为复杂,与煤焦油的性质及杂原子的含量有关,又受炼焦工艺制度和煤焦油加工条件的影响。表征煤沥青特性的指标很多,如沥青软化点、甲苯不溶物(TI)、喹啉不溶物(QI)、结焦值和煤沥青流变性等。

腰果酚应用研究进展..

12应用化学(职教本科1班彭思20120651 腰果酚应用研究进展 摘要:本文从官能团改性方面,综述了近几年国内外腰果酚衍生物的化学合成及在材料与精细化学品中的潜在应用,其中包括腰果酚酚羟基、腰果酚苯环及腰果酚侧链的改性。 关键词:腰果酚;腰果壳油;衍生物;应用;进展 前言:随着全球化石资源日趋减少,可再生资源的开发利用越来越引起人们的重视[1]。腰果壳液(CNSL)是腰果加工中的一种副产品,其含量约占腰果的25%-30%,世界年产量约50万吨,是一种价廉丰富的可再生资源[2-3]。CNSL 的最主要成分是腰果酚(cardanol)(1),含量可达90%。从结构来看,腰果酚属于苯酚的衍生物,在苯酚的间位被15个碳的直链(含0-3个碳碳双键)所取代(图1)(如无特殊说明,本文其它图中的R基团都代表腰果酚的侧链)。腰果酚可改性合成很多衍生物,包括功能小分子与聚合物,它们在涂料、摩擦材料、抗氧化剂、杀虫杀菌剂等方面都极具应用价值[4]。本文主要从腰果酚所含的三种官能团出发,总结通过酚羟基、苯环、不饱和侧链上的反应来制备各种有价值的腰果酚衍生物。 1利用腰果酚的羟基制备腰果酚衍生物 1.1腰果酚的酯类衍生物 腰果酚分子中含有活泼的酚羟基,可通过酯化、醚化反应制备相应的衍生物。例如张中云等[5]在-15℃左右使腰果酚与ClCN反应,生成腰果酚氰酸酯(2),2再与双酚A型氰酸酯(NCO-BPA-OCN)反应,制得了新型热固性树脂(图2)。由于树脂中引进了腰果酚所含的15个碳的柔性链,有效地提高了氰酸酯树脂的柔韧性,同时提高了其介电性能和耐吸水性能。

林金火课题组[6]用马来酸酐和腰果酚反应得到马来酸腰果酚单酯,然后与乙二醇进一步发生酯化反应 (图3),最后将酯化产物进行缩甲醛化反应,合成了同时具有软段结构(顺丁烯二酸乙二醇酯结构单元)和硬段结构(酚醛结构单元)的多羟基腰果酚醛树脂,该树脂具有优良的涂膜性能;所得的多羟基腰果酚醛树脂 也可与聚氨酯预聚体组成性能优良的双组分聚氨酯漆,可改善普通腰果漆的柔韧性和附着力。 为了制备新型抗氧化剂,Lomonaco等[7]用腰果酚和强心酚(cardol,腰果壳油的另一种成分)与二乙氧基硫代磷酰氯反应,制备了相应的硫代磷酸酯化合物(3)和(4)(图4)。将所制硫代磷酸酯在聚甲基丙烯酸甲酯中掺入1%的量,结果聚合物的热稳定性提高了很多。特别是化合物4中既含有硫代磷酸酯结构,又含有酚羟基结构,同时具有一类和二类抗氧化剂的功能,因此对材料的热稳定性提高最明显。

中国抗氧化剂的发展历程及使用技术问答

中国抗氧化剂的发展历程及使用技术问答 全球聚烯烃行业的突飞猛进,是与添加剂尤其是抗氧化剂的跟进发展分不开的。1958年瑞士的汽巴公司申请了全世界第一份抗氧剂1010发明专利。六十年代初,在瑞士巴塞尔建立了全球第一套抗氧剂1010生产装置,为全球聚烯烃,尤其是聚丙烯的快速发展和性能提高,提供了坚实的技术保障。 我国在上世纪60年代中期,曾与英国合作,在兰化公司建立了全国第一套年3000吨裂解沙子炉聚丙烯生产装置。抗氧剂1010是必备的添加剂。化学工业部把1010的研制任务下达到当时的北京市化工研究所。 1966年文革动乱爆发,1967年北京的科研院所解散,研究人员被下放到各地的厂矿企业。化工研究所参与抗氧剂研制的技术人员也下放到北京化工三厂。当时北京化工三厂抗氧剂1010研制小组的技术负责人是徐瑞林和化研所的张民生(他们后来成为北京市化工研究院的院长和总工程师)。郭永武任化工三厂抗氧剂小组试验员,后任车间工段长,责任工程师,车间主任等。 中国抗氧化剂发展的历程,大致分为四个阶段。 第一阶段,1966-1978年 主要是解决抗氧剂的有无问题。 首先要在实验室研制出抗氧剂1010的小试样品。最初确定的工艺路线分为五大步骤,当时的实验室条件简陋,技术资料缺乏,加之文革动乱的干扰,技术人员白天做实验搞研究,下班以后要参加

批判刘少奇邓小平及厂里的走资派,平时还要深挖批判自己"资产阶级知识分子"的所谓名利思想,出身不好的人要宣布与自己的反动家庭划清界限,其艰难的研究条件和巨大心理压力,是今天的年轻人无法想象的。因此研究工作进展的十分缓慢。差不多用了二年多时间,直到1969年春才拿出几百克的抗氧剂1010小试样品。当时的工厂军管会领导以此作为文革的巨大成果,向中共笫九次全国代表大会献礼。 1969年北京各大专院校师生全部下放到工厂接受"工人阶级再教育"。其中,北京大学化学系邢其毅教授和他的学生金声讲师被分配到化工三厂科研车间抗氧剂1010研制小组。他们的到来给抗氧剂的研发工作带来了新的生机和活力。合成步骤从原来的五步精减为三步。同时采用了苯酚烷基化技术,启动了国内生产26酚,24酚的新开端,同时又改进了剧毒的丙烯腈老工艺,釆用先进的26酚与丙烯酸甲酯加成路线。使国内抗氧剂1010的合成工艺路线与汽巴公司同步。 1970年在技术组长徐瑞林,张民生的带领下,北京化工三厂建成了一套年产十吨抗氧剂1010的中试装置,拿出了数吨的1010产品。1971年,通过了北京市化工局科技处组织的中试成果鉴定。与会代表一致认为,北京化工三厂科研车间研制开发的1010生产工艺路线成熟可靠,产品质量合格稳定,建议投入工业化大生产。

抗氧化剂的作用机理研究进展

抗氧化剂的作用机理研究进展 摘要:食品抗氧化剂的作用比较复杂。BHA和BHT等酚型抗氧化剂可能与油脂氧化所产生的过氧化物结合,中断自动氧化反应链,阻止氧化。抗坏血酸、异抗坏血酸及其钠盐因其本身易被氧化,因而可保护食品免受氧化。另一些抗氧化剂可能抑制或破坏氧化酶的活性,借以防止氧化反应进行。研究食品抗氧化剂的作用机理并合理使用抗氧化剂不仅可延长食品的贮存期,给生产者、经销者带来良好的经济效益,也给消费者提供可靠的商品。 关键词:抗氧化剂作用机理自由基现状前景展望 食品的变质,除了受微生物的作用而发生腐败变质外,还会和空气中的氧气发生氧化反应。食品氧化不仅会使油脂或含油脂食品氧化酸败(哈败),还会引起食品发生退色、褐变、维生素破坏,从而使食品腐败变质,降低食品的质量和营养价值,氧化酸败严重时甚至产生有毒物质,危及人体健康。防止食品氧化变质,在食品的加工和储运环节中,除采取低温、避光、隔绝氧气以及充氮密封包装等物理的方法还可以配合使用一些安全性高、效果大的食品抗氧化剂以防止食品发生氧化变质。 1 食品抗氧化剂的定义 食品抗氧化剂是指防止或延缓食品氧化,提高食品稳定性和延长食品储藏期的食品添加剂。具有抗氧化作用的物质有很多,但可用于食品的抗氧化剂应具备以下条件:①具有优良的抗氧化效果; ②本身及分解产物都无毒无害;③稳定性好,与食品可以共存,对食品的感官性质(包括色、香、味等)没有影响;④使用方便,价格便宜。[1] 2 食品抗氧化剂的分类 目前,对食品抗氧化剂的分类,按来源可分为人工合成抗氧化剂和天然抗氧化剂(如茶多酚、植酸等)。按溶解性可分为油溶性、水活性和兼溶性三类。油溶性抗氧化剂有BHA、BHT等;水溶性抗氧化剂有维生素C、茶多酚等;兼溶性抗氧化剂有抗坏血酸棕榈酸酯等。按作用方式可分为自由基吸收剂、金属离子螯合剂、氧清除剂、过氧化物分解剂、酶抗氧化剂、紫外线吸收剂或单线态氧淬灭剂等。[2] 3 食品抗氧化剂的作用机理 由于抗氧化剂种类较多,抗氧化的作用机理也不尽相同,归纳起来,主要有以下几种: 一是抗氧化剂可以提供氢原子来阻断食品油脂自动氧化的连锁反应,从而防止食品氧化变质; 二是抗氧化剂自身被氧化,消耗食品内部和环境中的氧气从而使食品不被氧化; 三是抗氧化剂通过抑制氧化酶的活性来防止食品氧化变质。 四是将能催化及引起氧化反应的物质封闭,如络合能催化氧化反应的金属离子等。[3]

聚氨酯

聚氨酯基本理论知识 一. 聚氨酯(polyurethane)大分子主链上含有许多氨基甲酸酯基: 它由二(或多)异氰酸酯、二(或多)元醇与二(或多)元胺通过逐步聚合反应生成,除了氨基甲酸酯基(简称为氨酯基)外,大分子链上还往往含有 醚基 、酯基、脲基、 酰胺基 等基团,因此大分子间很容易生成氢键。 二.聚氨酯主要原料 N H C O O O C O O NH O NH NH O

1、异氰酸酯及其结构特征 一、结构特点 在分子结构中含有异氰酸酯基团(-N=C=O)的化合物,均称为异氰酸酯(isocyanate),其结构通式如下:R-(NCO)n式中R为烷基、芳基、脂环基等;n=1、2、3….整数。在聚氨酯材料合成中,主要使用n≥2的异氰酸酯化合物。 二、异氰酸酯的分类 (1)异氰酸酯基团数量 1.异氰酸酯 异氰酸酯(Isocyanate)是一大类含有异氰酸基(—N=C=O)的 有机化合物。异氰酸酯基由于其累积双键和碳原子两边的电负性很 大的氮氧原子作用,使之具有很高的反应活性,能与绝大多数含活 泼氢的物质发生反应。常用的异氰酸酯主要有芳香族类和脂肪类两种。⑴芳香族类的主要有:TDI(2, 4—甲苯二异氰酸酯或2, 6—甲 苯二异氰酸酯)、MDI(二苯基甲烷- 4, 4’二异氰酸酯)、NDI (1, 5—萘二异氰酸酯)、PAPI(多亚甲基多苯基多异氰酸酯)等;芳 香族多异氰酸酯合成的聚氨酯树脂户外耐候性差,易黄变和粉化, 属于“黄变性多异氰酸酯”,但价格低,来源方便,在我国应用广泛,如TDI常用于室内涂层用树脂;聚氨酯树脂中90%以上属于芳香族

多异氰酸酯。与芳基相连的异氰酸酯基对水和羟基的活性比脂肪基异氰酸酯基团更活泼。基于TDI 的聚氨酯由于高的苯环密度,其力学性能也较脂肪族多异氰酸酯的聚氨酯更为优异。以下是一些常用的产品。 (1)甲苯二异氰酸酯(tolulene diisocyanate ,TDI ) 甲苯二异氰酸酯是最早开发、应用最广、产量最大的二异氰酸酯单体;根据其两个异氰酸酯(—NCO )基团在苯环上的位置不同,可分为2,4-甲苯二异氰酸酯(2,4-TDI,简称2,4-体)和2,6-甲苯二异氰酸酯(2,6-TDI ,2,6-体)。 室温下,甲苯二异氰酸酯为无色或微黄色透明液体,具有强烈的刺激性气味。市场上有3种规格的甲苯二异氰酸酯出售,T-65为2,4-TDI 、2,6-TDI 两种异构体质量比为65%/35%的混合体;T-80为2,4-TDI 、2,6-TDI 两种异构体质量比为80%/20%的混合体,其产量最高、用量最大,性价比高,涂料工业常用该牌号产品;T-100为2,4-TDI 含量大于95%的产品,2,6-TDI 含量甚微,其价格较贵。2,4-TDI 其结构存在不对称性,由于-CH3的空间位阻效应,4位上的-NCO 的活性比2位上的-NCO 的活性大,50℃反应时相差约8倍,随着温度的提高,活性越来越靠近,到100 ℃时,二者即具有相同的活性。因此,设计聚合反应时,可以利用这一特点合成出结构规整的聚合物。TDI 的弱点是蒸汽压大,易挥发,毒性大,通常将其转变成齐聚物(oligomer )后使用;而且由其合成的聚氨酯制品存在比较严重的黄变性。黄变性的原因在于芳香族聚氨酯的光化学反应,生成芳胺,进而转化成了醌式或偶氮结构的生色团。2,4-TDI 凝固点6-20度,TDI 的含量越高凝固点。 NCO CH 3NC O O CH 3 OCN 2,6-TDI 2,4-TDI

碳素材料简介

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