Showing papers in "Chemistry and Industry of Forest Products in 2007"

Chemical Composition Characteristics of Pinus latteri Mason Rosin and Turpentine from the South of Cambodia

Abstract: The chemical composition characteristics of Pinus latteri Mason rosin and turpentine from the South of Cambodia was studied using GC and GC-MSThe Pinus latteri Mason oleoresin was first separated into two fractions of rosin and turpentine oil,and they were analyzed qualitatively and quantitativelyNine components were identified from the rosin fraction including 8(14),15-pimaradiene,sandaracopimaric acid,isopimaric acid,8(9)-isopimaric acid,dehydroabietic acid,8,12-abietadienoic acid,abietic acid,neoabietic acid and mercusic acidThe proportions of pimarane-type,abietane-type,and dibasic resin acids were 4959 %,3718 % and 124 %,respectivelyThe main resin acids were isopimaric acid,8(9)-isopimaric acid,abietic acid and mercusic acid,and their contents based on rosin weight were 209 %,2114 %,2345 % and 1240 %,respectivelySixteen components in turpentine oil were determined including 13 monoterpenes,2 sesquiterpenes,and one diterpeneMonoterpene was the main component and accounted for 9949 % of turpentine oilThe main monoterpenes were m-mentha-4,8-diene,fenchene and alloocimene,and their contents in turpentine oil were 2401 %,2921 % and 2371 %,respectively

Synthesis of Epoxy Resin from Hydrogenated Terpinene-maleic Anhydride

Abstract: An alicyclolic epoxy resin with endocyclic structure,namely hydrogenated terpinene-maleic ester type epoxy resin(HTME), was synthesized from the raw material hydrogenated terpinene-maleic anhydride (HTMA).The obtimum synthesis conditions were confirmed by studying the effects on synthesis reaction of ratio of material, reaction temperature and time, dosage of catalyst,dosage and concentration of alkali and type of solvents.The epoxy resin was a transparent pale yellow liquid with epoxy value 3.5-3.9 mmol/g,viscosity 1.7 Pa·s at 50 ℃ and acid value 0.5 mg/g determined by chemical analysis methods, and its chemical structure was also characterized by FT-IR and NMR spectra.

Secondary Metabolites of Two Marine-derived Mangrove Endophytic Fungi (Strains Nos. 1924~# and 3893~#) by Mixed Fermentation

Abstract: Mixed fermentation technique was applied to culture two marine-derived mangrove endophytic fungi (strains Nos 1924# and 3893#) from the South China Sea in this paper The crude extracts from the fermentation liquids extracted by ethyl acetate showed significant bioactivities of killing pests Heliothis armigera Huhner and Sinergasilus spp in the primary bioassay Two secondary metabolites A and B were isolated from this crude extracts, and elucidated by spectral methods as 6-methylsali-cylic acid(A) and cyclo(phe-phe)dipeptide(B) respectively Compounds A and B were not obtained from these two strains by pure fermentation Compound A was responsible for the significant biocide activities of the crude extracts

Characteristics and Research Progress of Quinone Pigments

Abstract: Natural pigments have a few categories of quinone structure,which commonly include rubianic acid,gromwell pigment,alkanet color,jujube pigment,lac dye,carmine,et al.In this paper,characteristics of these quinone pigments are outlined,and progress of research on extraction and purification method of these pigments in recent years are overviewed.

Antibacterial Phenylpropanoid Glycosides from Paulownia tomentosa (Thunb.) Steud. Var. tomentosa Fruit

Abstract: Column chromatographic study on the aqueous acetone (70%) extract of Paulownia tomentosa (Thunb.) Steud. var. tomentosa fruit led to the isolation of 4 phenylpropanoid glycosides and their structures were determined as verbascoside (1), isoverbascoside (2) campneoside Ⅱ (3) and isocampneoside Ⅱ (4) by chemical and spectral analyses. Compounds 1-2 were isolated from the title plant for the first time. The study on antibacterial activity showed that the isolated compounds, acetone extract, EtOAc and H2O fractions exhibited significant inhibition, particularly against Staphylococcus epidermidis.

Stability of Lutein and Its Esters

Abstract: Stabilities of lutein and its esters against light, heat, acid, alkali, metal ions, oxidant and reductant were studied Results showed that both lutein and lutein esters were unstable against light, and stable in darkness Their preservation rate was 035 % toward outdoor sunlight for 05 h while they were preserved constantly in darkness They were slightly stable against heat but their degradation could be accelerated with decreased preservation rate under long time and high temperature Lutein ester was more stable toward light and heat than lutein under the same condition and esterification of —OH group with fatty acids might stabilize lutein against heat and light They were unstable with decreased preservation rate toward Fe3+,Fe2+, Cu2+ and strong acid while stable against Zn2+, Mg2+,Ca2+,K+,Na+, alkali and Na2SO3 as well as slightly stable toward H2O2 It was noted that VC could degrade significantly lutein esters and lutein, in which absorbance of lutein esters decreased more quickly than that of lutein

Research Progress of Application of Ultrasonic Technology to Biomass Resources Processing

Abstract: Technologies and applications of ultrasonic processing on biomass resources at home and abroad were reviewed.The theory of ultrasonic processing for plant extraction and their related extraction equipments in China were described.The ultrasonic applications for extraction of essential oil,natural pigment,polysaccharide,flavonoids,alkaloids,polyphenols,organic acids,vegetable oil,etc.were introduced.The ultrasonic processings for preparation of biodiesel fuel,hydrolysis of biomass resources and modification of biomass materials were also introduced.

Synthesis and Characteristics of Interfacial Coupling Agents for Agro-residues/Recycled Plastics Composite

Abstract: The new interfacial coupling agents, namely polyurethane prepolymer of isocyanate end group (PU)for wheat straw-recycled low density polyethylene(LDPE) composites were synthesized utilizing PAPI and polyether polyols as raw materials.The structure and characteristics of the coupling agents were analyzed by FT-IR spectroscopy, GPC and DSC.The relationship between material ratio and physical and mechanical properties of the prepared composites were evaluated.The results show that urethane is the reacting product and the existence of free isocyanate end group(—NCO)of PU,number-average molecular weights (Mn)of PU1 and PU2 are 4 370 and 7 230,distrbution indexs are 2.1 and 2.3,Tg are -65.5 and -41.2 ℃,respectively.Compared with the composite without coupling agents,the physical and mechanical properties of the composites using PU1 and PU2 are improved significantly,while effect of PU1 is superior to PU2. With 2.5 % PU1 coupling agent,the physical and mechanical properties of the composite exceed the standard GB/T 4897.6-2003 used for heavy-duty load-bearing boards in humid conditions.

Study on Extraction Conditions of Active Antiviral Substance from Walnut Leaves

Abstract: Antiviral substances of walnut(Juglans regia L.)leaves were extracted by different solvents and methods,and their antiviral activities were determined.The results showed that antiviral activity is dissimilar based on extracts from walnut leaves with different solvent and methods.For cold-leached extract with 95 % ethanol,when concentration inoculated is 10 g/L,inhibition rate on tobacco mosaic virus(TMV)of the extract was the best,100 %;optimum extraction condition of this extract is:95 % ethanol as solvent,ratio of material to solvent 1 ∶10,soaking time 18 h,extraction rate 21.42 %.The inhibition rate of the extract on TMV infecting Nicotiana glutinosa is 100 % when concentration inoculated is 5 g/L.Besides,an antiviral flavonoid A was isolated from ethyl acetate extract through column chromatography,thin layer chromatography and recrystallization.When its concentration inoculated is 0.5 g/L,inhibition rate of this compound on TMV infecting N.glutinosa is 85.55 %.The result indicated that compound A is one of the main antiviral components in ethyl acetate extract.

Preliminary Study on Antioxidative and Radical-scavenging Activities of Extracts from Myrica esculenta Buch.-Ham.Bark

Abstract: Myrica esculenta Buch.-Ham.is a species of perennial tree distributing widely in Southern China.Major components of extracts from M.esculenta bark are partially galloylated polymeric prodelphinidins.Based on the feature of chemical structure,anti-oxidation activities of prodelphinidins are stronger compared with procyanidins.Extracts from the bark were obtained by intensified extraction with water followed by separation and purification.The extracts are proanthocyanidins identified by anthocyanidin reaction and IR-spectra.Number-average molecular weight(Mn) of the extracts are respectively 1 705(95 %) and 798(5 %) determined by GPC and VPO.Galloylation degree at C-3 of the molecule were determined as 38 %.Bio-activity deter-mination showed that the extracts could evidently inhibit lipid peroxidation,complex metal ions(e.g.,Fe2+,181 mg/g) and scavenge free radical(e.g.,DPPH,scavenging speed 0.23 mg/min for 1 mg target extracts;scavenging rate 92 %,while mass ratio of extract to DPPH 1∶1.8).Results indicated that the extracts would be hopefully developed as a new type of natural antioxidant and radical-scavenging agent.

Study on Curing Reaction and Mechanical Properties of Epoxy Resin from Hydrogenated Terpinene-maleic Anhydride

Abstract: Hydrogenated terpinene-maleic ester type epoxy resin(HTME) is a type of epoxy resin synthesized from hydrogenated terpinene-maleic anhydride.The activity of curing reaction of HTME/methyl hexahydrophthalic anhydride(MeHHPA) system was investigated by means of DSC and gelation time determination.The curing behaviors of HTME/MeHHPA system were studied by qualitative analysis of FT-IR spectrum and quantitative analysis of curing degree determination.The mechanical properties of HTME cured with MeHHPA were compared with those of terpinene-maleic ester type epoxy resin(TME) and epoxy resin 6101 under the same condition.The results show that the reaction between HTME and MeHHPA was an exothermic one with reaction heat of 153.5 J/g and peak temperature at 157.9 ℃,and the HTME/MeHHPA system could be cured completely at 110 ℃ for 8 h with 0.5 % benzyldimethylamine(BDMA) by weight of HTME as accelerant.The mechanic properties of the three kinds of cured epoxy products were about the same.

Isolation,Purification and Identification of Flavonoids in Vaccinium bracteatum Thunb. Leaves

Abstract: Flavonoids in Vaccinium bracteatum Thunb. leaves were studied. The chemical constituents of leaves were isolated by solvent extraction and column chromatography. Four compounds were isolated and identified to be chrysin (Ⅰ), apigenin (Ⅱ), kaempferol(Ⅲ) and luteolin(Ⅳ) by HPLC, MS and NMR spectroscopies.

Study on catalytic cracking of tar derived from biomass pyrolysis and gasification.

Abstract: Main raw material is poplar sawdust.Catalytic cracking of tar is performed in a secondary fixed-bed cracking reactor using four types of dolomite as catalyst.Operation parameters like cracking temperature,catalyst type and residence time of reaction are investigated for their influences on tar cracking and gas quality.The characters of catalysts from different areas are measured in order to seek for suitable catalyst for commercial utilization in gasification systems.The results show that higher cracking temperature and longer residence time are favourable to tar cracking.When pyrolysis temperature goes beyond 1 000 ℃,the tar cracking rate can reach 98.99 %.Dolomites from different places show obvious difference in their catalysis effect.The dolomite from Shaanxi calcined at 900 ℃ can have tar cracking rate up to 95.14 %.The most important factor that determines cracking effect of dolomites is their specific surface area after calcination.The bigger the specific surface area the better is catalysis effect.In order to obtain high catalysis effect,dolomite with bigger specific surface area should be chosen.

Studies on Lipophilic Chemical Constituents from Passiflora wilsonii Hemsl. Stem

Abstract: From the stems of Passiflora wilsonii Hemsl., six compounds,namely 4-oxo-3,4-seco-A(1)-norfriedelan-2-oic acid(Ⅰ),2-hydroxyl-3,4-seco-friedelan-3-oic acid ethyl-ester(Ⅱ),sitost-4-en-3-one(Ⅲ),3-(2,4-dihydroxyphenyl)-2-propenoic acid(Ⅳ),glycerol 1-octadecanoate(Ⅴ),and 1-octacosanol(Ⅵ),were isolated from its lipophilic components and identified.Compound Ⅰ is a novel natural product,whose 13C NMR spectra were assigned for the first time.Compound Ⅱ is a new artificial compound.

Study on Complexation Properties of Black Wattle Tannin with Metals Ions

Abstract: Protonation constants and metal-complex stability constants of tannic acid,valonea tannin and black wattle tannin were determined by pH potentiometric titration under different temperatures in ionic strength I=0.1 mol/L NaCl solution.The complexation selectivities of different structures of tannins with Fe3+,Cu2+,Zn2+,Ni2+ ions were investigated and factors affecting protonation constant and stability constant were discussed.The results showed that the order of stability constants of the tannins complexed with Fe3+,Cu2+ ions was:black wattle tanninvalonea tannintannic acid,and that of tannins with Zn2+,Ni2+ ions was:valonea tanninblack wattle tannin tannic acid.The rise of temperature was favorable for disassociation of phenol hydroxyl but unfavorable for the formation of complex.The purification of black wattle tannin by gel column chromatography showed little effect on the complex stability constants.

Study on Extraction and Purification of Betulin from Birch Bark

Abstract: The technological conditions for extraction and purification of betulin from the outer bark of white birch were investigated.The suitable extraction conditions were determined as follows: amount of bark 30 g,the size of bark particle 0.42-1.16 mm,chloroform was used as extraction solvent,extraction time 7 h.The yield of light-yellow crude extract obtained under aforesaid conditions reached 38.5 %.Betulin with high purity was obtained by recrystallization,and the suitable recrystallization conditions were determined as follows: isopropanol was a suitable solvent for recrystallization of betulin,and the ratio of crude extract/isopropanol was 1 ∶20(g ∶mL);crystallization temperature-5 ℃,crystallization time 1 h.The yield of betulin was 41.4 %,melting point was 245-254 ℃,and purity was 95.4 %.

Antioxidant Activities of the Extractives of Larix kaempferi Carr. Fresh Needles

Abstract: Seven compounds,including three flavan-3-ols,(+)-catechin(1),(-)-epicatechin(2) and(+)-gallocatechin(3),three flavonoid glycosides,isorhamnetin-3-O-β-D-glucopyranoside(4),astragalin(5) and 2″-O-rhmnosylvitexin(6),and one lignan with the trivial name cedrusin(7),were isolated for the first time from the fresh needles of Larix kaempferi C.Their structures were elucidated by chemical and spectral analysis.The antioxidant activities of the crude extracts,partitioned fractions and isolated compounds were evaluated by DPPH free radical-scavenging assay.Results suggested that EtOAc participated fraction and the three flavan-3-ols showed significantly high antioxidant potential compared with α-tocopherol and BHT,which were used as controls.

Study on Liquefaction of Walnut Shell in Phenol and Application of Its Resinification Product as Wood Adhesives

Abstract: Liquefaction of walnut shell in phenol using sulfuric acid as catalyst was investigated under different conditions of mass ratio of phenol to walnut shell,dosage of catalyst,reaction time and temperature.Results showed that with the increasing of phenol/walnut shell ratio from 2/1 to 5/1,the amount of residue decreased from 26.49 % to 6.60 %.With dosage of catalyst from 2 % to 4 %,reaction time from 5 to 120 min and temperature from 100 to 150 ℃,the amounts of residue decreased from 20.79 % to 10.48 %,48.84 % to 15.62 % and 28.86 % to 9.39 %,respectively;the contents of unreacted free phenol decreased from 17.32 % to 12.67 %,41.71 % to 10.25 % and 21.94 % to 14.33 %,respectively too.Weight average molecular weight(MW) and degree of polydispersity of resultants of liquefaction decreased to 706-1 030,1.04-1.25,respectively.The high-molecular weight part of liquefaction product decreased with increasing of phenol/walnut shell ratio,but increased with the increasing of H2SO4 concentration,reaction time and temperature.Compared to conventional phenol-formaldehyde(PF) resin adhesives,the liquefied walnut shell/phenol/formaldehyde co-condensed(WPF) resin can be used as adhesives for plywood with its bonding strength of 1.33 MPa.

Investigation on Biological Activities of Proanthocyanidins from Black Wattle Bark

Abstract: The extraction conditions of proanthocyanidins from bark of black wattle (Acacia mearnsii De Wilde) and their biological activities were investigated in this study. Different types of solvents such as water, methanol and ethanol were used as extraction solvent, respectively. Experiments were conducted to study the effects of temperature, liquid-solid ratio and concentration of ethanol on the extraction efficiency. The focus of this study is to evaluate the biological activities of the extracted proanthocyanidins products. The anti-tumor activity of proanthocyanidins was determined by MTT colorimetric method, and DPPH method referred to the radical scavenging capacity was used to test the anti-oxidation ability of the proanthocyanidins. The results showed that black wattle bark is rich in proanthocyanidins. Ethanol was considered to be a suitable solvent, in which there was higher extract yield and stronger biological activities of proanthocyanidins. It was found that the optimum conditions of extraction were as follows: concentration of ethanol 70 %, temperature 60 ℃,and the ratio of solution to solid 7 ∶1. Furthermore, the results of anti-tumor test of proanthocyanidins crude products on human cancer cells cultured in vitro showed that the proanthocyanidins had medium effect on promyelocytic cell line HL-60, weak effect on human stomach adenocarcinoma BGC-823 and human hepatocellular carcianoma BEL-7402. Meanwhile, the results of radical scavenging ability assay indicated that the proanthocyanidins had strong anti-oxidation activity.

Preparation of Nano-crystalline Cellulose/Polyethylene Glycol Solid-solid Phase Transition Material and Its Energy Storage Characteristics

Abstract: A new kind of solid-solid phase transition material(PCM)was prepared.The material is composed of two parts,in which polyethylene glycol(PEG)is the functional surface for energy storage and nano-crystalline cellulose(NCC)is the skeleton.The flexible polymer PEG was grafted onto the surface of the rigid polymer NCC through covalent bonds.Furthermore energy storage properties of PCM were studied by means of FT-IR,DSC,TGA,etc..Results show that PCM possesses high enthalpy of phase transition up to 103.8 J/g,and high efficiency of energy storage.

Study on Determination of Holocellulose Content of Bamboo by Near-infrared Reflectance Spectroscopy

Abstract: A rapid determination of holocellulose content of bamboo (Phyllestachys heterocycla (Carr.)Mitford cv.pubescens) has been developed by near-infrared reflectance spectroscopy (NIR)coupled by multivariate statistical analysis technique. The holocellulose contents of 54 samples were analyzed with traditional wet chemical technique, the spectra of which were collected by NIR. After the spectra were converted to the second derivative spectra with a gap of 25 nm, the prediction model for the holocellulose content of bamboo samples was established using partial least-square regression (PLS1)and full cross validation in the range of 1011[KG-*2]-[KG-*6]1675 nm and 1930[KG-*2]-[KG-*6]2488 nm. High correlations were obtained between the predicted NIR results and those obtained from traditional chemical method. The correlation coefficient of prediction model is 0.95 and standard error of prediction (SEP) is 0.76 %.

Synthesis and Property of Superabsorbent Polymers Modified by Carboxymethyl Cellulose

Abstract: Acrylamide(AM),and [2-(methylacryloyloxy)ethyl] trimethylammonium chloride(MAETAC) were grafted onto carboxymethyl cellulose(CMC) to prepare cellulose-modified cationic superabsorbent polymers(SAP) by inverse suspension copolymerization.Factors affecting water-absorbent capacity were investigated in detail,which were found to be as follows: ratio of oil to water 2∶1,dosage of Span 60 and Tween 80(3∶1),5 % of water phase,pH value 4,CMC dosage 5 %,content of initiator(NaHSO3,(NH4)2S2O8)2.5 %,and crosslinking agent 0.5 % of the weight of monomers,reaction temperature 65 ℃,reaction time 2 h.The cellulose-modified cationic SAPs prepared under optimum conditions were obtained which have the absorbent capacity of 657 times their own weight in distilled water and 116 times in 0.9 % salt solution under optimized synthesis condition.

Chemical Constituents of Volatile Oil from Leaves of Microcos paniculata L.

Abstract: The volatile oil from leaves of Microcos paniculata L. was obtained by steam distillation. The chemical constituents were separated and identified by GC-MS. Relative contents of volatile oil were determined by peak area normalization. The yield of oil by steam distillation was 0.63 %, and 15 compounds from the volatile oil were separated and identified, which account for 99.99 % of total volatile oils. The main chemical constituents were 2-methoxy-4-vinylphenol (18.12 %), octacosane (11.77 %), n-hexadecanoic acid(11.29 %), pentacosane(10.32 %), heptacosane(8.61 %), 2,3-dihydro-benzofuran (6.29 %), tetratetracontane(5.99 %) and hexatriacontane (5.51 %).

Study on Chemical Constituents of the Leaves of Canarium album (Lour.) Raeusch

Abstract: Chemical constituents of the leaves of Canarium album(Lour.)Raeusch were studied.Eight compounds were isolated from ethylacetate extract of the leaf,and their structures were elucidated by various spectroscopic methods.They were identified as ethyl gallate(Ⅰ),scopoletin(Ⅱ),gallic acid(Ⅲ),amentoflavone(Ⅳ),myo-inositol(Ⅴ),quercetin(Ⅵ),β-sitosterol(Ⅶ)and 4,5-didehydro-chebulic acid triethyl ester(Ⅷ).Compound Ⅷ is a novel compound and compounds Ⅴ and Ⅵ were obtained from this genus of plant for the first time.Compounds Ⅳ and Ⅶ were isolated from this plant for the first time.

Experimental Study on Preservation Performance and Acute Toxicity of Maackia amurensis Rupr. et. Maxim. Heartwood Extracts

Abstract: The heartwood and bark of Maackia amurensis Rupr.et.Maxim.were used as raw material to obtain 10 kinds of extracts by extracting with ether,chloroform,acetone,methanol and water,respectively.Antibacterial activities against Coriolus versicolor and Gloeophyllum trabeum of 10 kinds of extracts were studied,It was found that methanol and acetone extracts of heartwood have good antibacterial activities.Wood preservation activities of methanol extract of heartwood was also compared with the wood preservative acid copper chromate(ACC) in lab.Weight loss and scanning electron microscopy(SEM) photography showed that methanol extract of heartwood has better decay resistance against C.versicolo,weaker decay resistance against G.trabeum,but ACC has better decay resistance against two epiphytes.The acute toxicities of methanol extract of heartwood and ACC to Brachydanio rerio were studied.At 24,48 and 72 h,LC50 of methanol extract were 16.5,12.7,12.0 mg/L respectively,LC50 of ACC were 3.2,2.5,2.0 mg/L respectively.The safety concentrations of methanol extract and ACC are 2.26 and 0.46 mg/L respectively.

Extraction of Juglone from Bark of Juglans mandshurica Maxim. by Vacuum Distillation

Abstract: Juglone(5-hydroxy-1,4-naphthaoquinone) is one of the active substances that was extracted from Juglans mandshurica Maxim.Juglone product was obtained from bark of J.mandshurica by ultrasonic extraction and vacuum distillation,and the yield of product was 0.09 %.The product was characterized by FT-IR,GC-MS and 1H NMR.The result showed all the characteristic absorption peaks of hydroxyl-naphthaoquinone in the FT-IR spectrum of the product.The constituents of the product were determined by GC-MS to be: 1,4-naphthaoquinone,5-hydroxy-1,4-naphthaoquinone and 7-methoxy-1-tetralone,and the content of juglone in the product was 96.42 %.The structure of juglone in the product was confirmed by 1H NMR.This study offered a simple and effective method to get high purity juglone from bark of J.mandshurica.

Antifungal Activities and Active Components of Alcoholic Extracts from Leaves of Juglans mandshurica Maxim.

Abstract: The extracts from leaves of Juglans mandshurica Maxim. were obtained by common extracting method for studying its antifungal activities and analyzing the active components.The results showed that alcoholic extracts and the acetic ether part of alcoholic extracts (separated with acetic ether from alcoholic extracts) from leaves of J. mandshurica had antifungal activities toward Alternaria alternate Fr. and Sphaeropsis sapinea Fr.. MIC of the alcoholic extracts and the acetic ether part of alcoholic extract were both 3.12 g/L toward A. alternate,and both 6.25 g/L toward S. sapinea. The active components in the acetic ether part I and part II(separated with silica gel column chromatography) of alcoholic extracts from leaves of J. mandshuricawere analyzed by GC-MS.The results showed that major active components of relatively high content in the acetic ether part of alcoholic extracts from leaves ofJ.mandshuricawere 1,4-naphthalenedione,5-hydroxy-(juglone),D-allose,5,8-dihydroxy-1,4-naphthalenedione,1,5-naphthalenediol,2,3-dihydro-benzofuran,7-methoxy-1-tetralone,1-naphthalenol,8-hydroxy-2-methoxy-1,4-naphthalenedione and 4-methyl-2,6-dihydroxyquinoline.

Study on Preparation and Certification of Reference Substance of Bornyl Acetate

Abstract: Preparation,homogeneity,stability and certification of reference substance of bornyl acetate were studied.The reference substance of bornyl acetate was prepared by acetylation of highly pure borneol isolated and purified from a natural borneol product.The content of bornyl acetate in reference material was measured by gas chromatographic area normalization.The reference substance of bornyl acetate passed the test of homogeneity,and it was stable during 24 months at least.The joint certification results of bornyl acetate reference substance through multiple labs showed that the standard value of bornyl acetate content was 99.93 % with standard uncertainty of 0.08 %,extended uncertainty of 0.16 % and confidence coefficient of 95 %.