1, All vehicles come with a catalytic converter as standard.

2, Governments do, however, have a vital catalytic role in orchestrating rescue operations.

3, A catalytic converter will cut out 90% of carbon monoxide emissions.

4, Every Saab now has a catalytic converter.

5, Three-way catalytic converters are standard on all models.

6, The effluent from the catalytic reactor is cooled and combined with an aqueous solution of a basic compound.

7, And if your car is fitted with a catalytic converter(), Shell Advanced will help enhance the catalyst's performance.

8, Then it is combined with hydrogen in a catalytic converter to produce methane gas and water.

9, All new cars today must have expensive catalytic converters to reduce emissions.

10, Catalytic converter technology would be forced to advance at a much improved rate, showing that F1 does indeed improve motoring in general.

11, Process Description Catalytic hydrogenation of contaminated organic waste streams is carried out at moderate temperatures and pressures.

12, The Tipo has a three-way catalytic converter and exhaust gas recirculation valve.

13, In acute pancreatitis, the catalytic activity of PLA2 in serum correlates with the severity of the disease.

14, Because no other small cars come with a catalytic converter as standard.

15, Volvo, however, is now offering to fit catalytic converters free on all newly-bought models.

16, Extensive facilities for evaluation of catalytic activity include Auger electron spectroscopy and diffuse reflectance and transmission Fourier transform infrared spectroscopy.

17, Catalytic reaction kinetics are favourable over a wide range of pressures, temperatures and flow rates.

18, All 605s are fitted with a three-way catalytic converter, anti-lock braking system and an ultrasonic alarm as standard.

19, In addition to better economy,(http:///catalytic.html) diesel cars use cheaper fuel and are no less environmentally-friendly than petrol-engined models fitted with catalytic converters.

20, For example, plasticity seems to depend on identifiable ion channels and catalytic molecules that activate or inhibit these channels.

21, Both of these non-conserved amino-acid substitutions would have highly detrimental effects on the catalytic function of the putative protein-tyrosine kinase.

22, Even proteins formed as a random sequence of amino acids have some slight catalytic activity.

23, The exhaust emissions standards could only be met with current technology by installing three-way catalytic converters in petrol-driven vehicles.

24, Motorists should not park their cars in tall grass, because mufflers and catalytic converters can be hot enough to ignite fires.

25, Vauxhall retaliated by knocking up to ￡1,150 off 1992 Novas and Cavaliers not fitted with catalytic converters.

26, Examples used to illustrate the theme included photographic film and a sectioned catalytic converter.

27, Budapest is to ban all cars with two-stoke engines from the city centre unless they are fitted with a catalytic converter.

28, As you'd expect, being a Saab, it runs on unleaded fuel and has a 3 way catalytic converter.

29, Some manufacturers are already offering to retrofit old models with catalytic converters.

30, The gas phase is recycled to the reactor inlet to provide a large excess of hydrogen gas in the catalytic reaction zone.

31, A green transport policy Using unleaded petrol and fitting catalytic converters will dramatically reduce the levels of pollution caused by vehicle emissions.

32, Existing catalytic converters can produce extremely low hydrocarbon and carbon monoxide outputs only in optimal conditions.

33, All Safranes are fitted with three-way catalytic converters as standard.

34, As governments embrace a more catalytic role, they are often forced to develop new organizations to manage the steering role.

35, Anoraks will remember the McLaren went faster but that was without power-sapping catalytic converters.

36, The remaining gases pass through a catalytic converter to further reduce pollution.

37, The model included standard goodies such as electric windows and mirrors all round, power steering, central locking and catalytic convertor.

38, They are largely removed from motor vehicles by catalytic converters.

39, Our engineers have incorporated a 3-way catalytic converter into an advanced engine design that reduces toxic gases by up to 95%.

40, A catalytic unit blast at the refinery in 1983 killed one worker.

41, They will function as a catalytic link between the universities and the illiterates them-selves.

42, In built-up areas, for example, special slow-reacting catalytic surfaces will automatically enforce the speed limit.

43, Peregrine Phillips took out a patent in 1831 for the contact or catalytic process for the manufacture of sulphuric acid.

44, The company also looks set to prosper from making the substrates which go into catalytic converters used to clean car-exhaust emissions.

45, Union Carbide have patented a process for the catalytic conversion of synthesis gas to ethylene glycol.

46, Finally, the chemistry of the stratosphere is dominated by the photochemical production and catalytic destruction of ozone.

47, It is known as catalytic cracking.

48, The first catalytic converters were called conventional oxidation catalysts.

49, Many other important catalytic parameters were deduced.

49, try its best to gather and make good sentences.

50, Especially in the field of sensors and catalytic power.

51, The dimethylbenzenes are obtained from catalytic reformate.

52, METHODS: It was synthesised using phase transfer catalytic method.

53, The V6 engine also features exhaust gas recirculation, an oxidising catalytic converter and a maintenance-free diesel particulate filter.

54, Results: The synthesized antigen induced catalytic antibodies with high efficiency in catalyzing hydrolysis of nerve agent soman and a novel phospho -transesterification reaction was discovered.

55, Compared with traditional way, catalytic aromatization of isophorone has been proved to have many advantages.

56, It exhibited good catalytic activity for the hydrosilylation of olefins, such as decene, do-decene, w-chloroundecene, ...

57, The formation of camphor from the catalytic dehydrogenate of isoborneol in gas phase was investigated and catalyst CDH has been selected.

58, The catalytic activity of the succinimide resin for hydrolysis of esters was studied.

59, Typical chitinases have a N-terminal signal region, a catalytic domain and a C-terminal region, but some chitinases have one or more chum-binding domains.

60, We can expect any sufficiently complex set of catalytic polymers to be collectively autocatalytic .

61, Formation influencing factors are carbon, chlorine, temperature, catalytic agents, oxygen et al.

62, The actual application of the catalytic fluorimetry in the determination of the inorganic substance, organic substance and enzyme, etc. was introduced.

63, The technologies for synthesis ofp-nitroanisole by using the triphase catalytic method, and synthesis ofp methoxyaniline by use of reduction of synthesized p-nitroanisole were studied.

64, This paper summarizes the types of hydrogen-producing microbes, the research on biohydrogen metabolism and the catalytic mechanism of hydrogenase , and brings forward the prospect.

65, Furthermore, two synthesising routes are compared and the research of catalytic aromatization of isophorone is summarized in this paper.

66, This method triumphantly decreased the usage of noble metal and enhanced the catalytic activity, which could replace the traditional chemical plating activation pretreatment.

67, The air guards the catalytic converter from overload and possible resulting damage.

68, Regular carbon micro-coils were obtained by a catalytic pyrolysis method with acetylene as a carbon resource and Ni as a catalyst and thiophene as a promotor.

69, To more understand the catalytic mechanism and to prepare for the future megascopic experiments, kinetics of methylolation had been studied, either.

70, A home made catalytic additive and DS silver tarnishing prevention agent have been used in a new silver electroplating technology.

71, Especially by the TS-1 modified with trimethylchlorosilane, much higher catalytic activity was achieved than by parent TS-1 zeolite in the phase-boundary catalysis.

72, India' s policy and actions promotes and accelerates the emergence of Bangla Desh, so India playes an catalytic role in the course of the disunion of Pakistan.

73, A mathematical model was established to simulate the light - off performance of a catalytic converter.

74, When catalytic converters were developed, the petroleum industry had to make gasoline lead - free.

75, A mathematical model was established to simulate the light-off performance of a catalytic converter. Simulation results and the experimental values are agreed well.

76, By means of analysis on ignition fail reason of auxiliary combustion chamber for catalytic cracking unit, the unreasonable place existed in igniter was found, and improvement plan was given.

77, Catalyst is the key part of selective catalytic reduction(SCR) system, and its catalytic behavior directly affects the efficiency and economics of NOx reduction.

78, A new method for the determination of trace lead by adsorptive catalytic voltammetry has been established.

79, Catalytic transfer hydrogenation (CTH) is an effective reduction method, which conducts at a mild reaction condition and with simple facilities comparing to common catalytic hydrogenation.

79, Wish you can benefit from our online sentence dictionary and make progress day by day!

80, L-Asp6-Ibuprofen was prepared by mixture anhydrides methods and DCC/HOBt methods. The benzyl group of the product was deprotected by catalytic hydrogenation.

81, Effecrts of calcium modified ZSM-5 zeolites and reaction conditions on the catalytic activity and selectivity of toluene ethylation have been studied.

82, The synthesis ofp phthalaldehyde from p xylene by chlorination and catalytic oxidation was studied. The total yield was over 89%, the purity of the product was over 99%.

83, The proposed system has been successfully applied to a large production scale catalytic cracker.

84, The results show that the catalytic efficiency of complicated catalyst of tin( II) chloride dihydrate andp -toluene-sulfonic acid is higher than that of the others.

85, The preparation methods of C9 petroleum resin, including thermal polymerization, catalytic polymerization, radical polymerization were summarized and compared.

86, The factors influencing coking within resid fluid catalytic cracking ( RFCC ) disengagers and the mechanism are analyzed.

87, The measurement of catalytic surface area has been, is, and will continue to demand considerable research.

88, A new process has been developed to synthesize p-aminophenol methyl ether from p-nitrophenol methyl ether by catalytic hydrogenation, using ammonia synthesis gas instead of pure hydrogen.

89, The dominant reaction pathways and the effect of reaction temperature and type of zeolites on the yield and selectivity of benzene formed during catalytic cracking of cumene were investigated.

90, The Fluid Catalytic Cracking ( FCC ) is the major gasoline - producing process in refinery.

91, The lumping strategies of catalytic cracking reaction and their reaction networks are concluded, their advantages and disadvantages are discussed.

92, This paper deals with the salt bath chromizing techniques and the effect of RE as a catalytic agent in salt bath on T12A steel chromizing technique, layer microalloying, structure and properties.

93, The high efficiency steam stripping technology of catalytic cracking unit can efficiently decrease the coke yield, and mitigate the regenerator's load.

94, Orthochlorophenylacetic acid was synthesized from industrial grade o-chlorotoluene via catalytic chlorination, phase transfer catalytic cyanogenation and mixed acid catalytic hydrolytic reaction.

95, Catalytic cracking of pinane was obviously superior to thermal cracking.

96, Menthol was obtained from lemon eucalyptus oil via cyclization and catalytic hydrogenation.

97, C9 aromatic petroleum resin was produced with pressure thermal polymerization instead of the catalytic polymerization under low temperature.

98, This provides a novel approach to tune the catalytic behaviors of metal catalysts for the involving hydrogen reactions, which are sensitive to the electronic state of the active components.

99, Catalytic reduction of nitrate in groundwater by sodium formate was conducted.

100, The preparation of HFC - 32 by catalytic hydrogenation of CFC - 12 was explored.

101, Varied fluid catalytic cracking slurries reacted with hydroxymethy were used to synthesize pitch resins.

102, The catalysts were characterized by means of TPD, XRD and TPR and their catalytic mechanisms discussed.

103, The technique process of compounding unit of catalytic agent of HDPE plant, control procedures and requirements are introduced. Relevant control strategy is studied and made.

104, The tetrachloroethylene carbonate is decomposed by heating same with a catalytic amount of a tertiary amine or amide.

105, This paper discusses the fundamentals and characteristics of catalytic combustion and the type of catalyst and approaches the way to apply the technology of catalytic combustion in cremator.

106, A heterogeneous catalytic system for methylolation of alkali lignin was constituted of tetrahydrofuran containing purified alkali lignin and solid alkali catalyst with special structure .

107, When hyperglycaemia, may cause the above enzyme the zymoprotein glycosylation, the catalytic activity to reduce, crosses the free time hydrogen and the oxygen free radical elimination reduces speed.

108, Two transient models have been developed to study the catalytic ignition in a monolithic catalytic reactor.

109, The denitration by dry process were investigated from the view of governing technology. Including catalytic reduction(/catalytic.html), absorption and plasma.

110, Dirmethyl ether ( DME ) Can be synthesized catalytic dehydration of methanol.

111, They have begun to be used in catalytic sensor and ionic conduction too.

112, A process for the preparation of trimesic acid by the catalytic oxidation of mesitylene with air in liquid phase was presented in this paper.

113, The ammonia synthesis catalyst exhibited higher intensity and catalytic activity low temperature, and good thermal resistance.

114, Influence of support and preparation condition on catalytic behavior of copper-based catalysts for one-step synthesis of butyraldehyde were studied.

115, In toluene disproportionation, the catalytic activity is effected by the acidity and crystal size of catalyst.

116, And the relevant suggestion for developing trend of catalytic cracking process and catalyst is pointed out.

117, Deregulation's catalytic power. is still reshaping the banking, communications, and transportation industries ( Ellyn E. Spragins ).

118, Quinoline catalytic cracking was studied on a fixed-bed microactivity test unit by using toluene, cetane, and tetralin as solvent.

119, Catalytic synthesis of phenetole by ethylation of phenol with diethyl carbonate(DEC)in fixed bed reactor was investigated.

120, In the liquid-phase hydrogenation of nitrifying mixture, four elements Raney Nishows excellent catalytic activity and strength, compared with many kinds of catalyst.

121, The invention discloses an octanol hydrorefining catalyst, which belongs to the field of hydrorefining catalytic materials.

122, A method, which combined neural network and genetic algorithms, was employed to simulate the catalytic distillation process by black box model and optimize the operational parameters.

123, In the geometrical figures of equilateral triangles or scalene triangles, the semantic view, pragmatic view and cognitive theory view have played a profound and catalytic function.

124, Some catalytic systems for the synthesis of glutaraldehyde by one step catalytic oxidation of cyclopentene and hydrogen peroxide in a non water solvent were studied.

125, The factors that influence the catalytic activity of catalysts and the efficiency of catalytic ozonation are discussed, and the catalytic properties of various metal and metallic oxides are reviewed.

126, The feasibility of commercialization of emulsified residue catalytic cracking was analyzed based on theories of explosive atomization and molecular accumulation and disaggregation .

127, In this article, the influence of curing condition on the coating , catalytic difference of two kinds of platinum catalyst , and influence factors on the release force were studied respectively.

128, Typical components in such a blend could be isooc'tane, alkylate and catalytic reformate.

129, The results show that ore particle size has an important impact on catalytic bioleaching of low-grade primary copper sulfide ore with activated carbon.

130, Latest advances in the gaseous phase catalytic synthesis of difluoromethane and the preparation of catalysts are summarized.

131, Another reason for banning lead in gasoline is that the lead can ruin the catalytic converter.

132, The high level of HC in the exhaust gas may damage the catalytic converter.

133, Objective To study the catalytic activity of potassium bisulfate in synthesizing hexyl hexanoate.

134, By applying multivariable model predictive control (MPC) technology, the control performance of the gasoline debutanizer of fluid catalytic cracking unit can be improved.

135, The result showed that the advantages offered by the catalytic combustor is that catalytic combustion can be carried out over a wide air: fuel ratio and at low temperature with high heat efficiency.

136, The influence of the calcination temperature on the catalytic activity of zeolitefor the reaction of o-xylene isomerization was investig.

137, High catalyst to oil ratio mainly leads to carbenium ion catalytic reaction, which LPG and coke yields were remarkably increased but dry gas yield was basically unchanged.

138, Progress in a variety of catalytic systems - catalyzed dimerizations of terminal alkynes to synthesize enynes is summarized.

139, Objective To study the catalytic activity of ceric sulfate in the synthesis of butyl acetate.

140, The catalytic hydroxyethylation of liquid ammonia by cation exchange resin was studied and the reaction mechanism was discussed. According to the experimental data,() the kinetic equation was deduced.

141, The catalytic activity of histidase and the expression of the enzyme protein were investigated in rat hepatomas induced by diethylnitrosamine.

142, Metal passivator can inhibit nickel and vanadium pollution on the catalytic cracking catalysts and improve the property of polluted catalysts.

143, Induction and inhibition of cytochrome P 450 ( CYP 450 ) catalytic activity has been concluded to be pharmacokinetic drug - drug interaction.

144, Moreover, aptazymes as catalytic molecular beacon provide a new orientation for analysis of effector molecules.

145, The analytical data shows that reduced crude is an ideal feedstock for the Residuum Catalytic Cracker.

146, In order to intensify the process of methanol steam reforming, the effect of catalytic surface distribution on this reaction was investigated.

147, Tetraethyl lead worked leaded gasoline but was phased out because It'spoiled catalytic converters.

148, The process is considered by some refiners as a supplement to the basic catalytic cracking process.

149, There are inherent difficulties in selecting any method as a standard for catalytic surface area determinations.

150, The physical chemistry properties of ozone and its application in water treatment are reviewed, and the emphasis of discussion is put on metal catalytic ozonation technology developing recently.

151, The title curing agent has been prepared by one - step catalytic polymerization process with a specific chemical additive.

152, The catalytic activity of tungsten carbide was studied through hydrogenation of benzene.

153, The importance of implementing fast aging method for catalytic converter is firstly described in this paper, then the fast aging test equipment and test procedure we adopted are introduced.

154, This article reviews the study on the synthesis of tert - butanol from isobutylene in residual C4 by catalytic hydration with concentrated heteropoly acid (HPA).

155, Hexamethylphosphoric triamide(HPT) was added as toughened modifier in anionic catalytic polymerization of caprolactam to prepare modified MC nylon.

156, Hydrogen transfer is one of the characteristics of catalytic cracking reaction.

157, HSBR ) was prepared by hydrogenating styrene - butadiene rubber ( SBR ) latex with hydrazine hydrate - hydrogen peroxide - copper sulfate catalytic system.

158, The application of catalytic distillation reactor in benzene alkylation process is presented.

159, The micro-structure of Y zeolites is closely related to its stability and catalytic properties.

160, We have prepared several complex catalyst of stannous chloride and rare earth chloride to replace mercuric chloride and examined their catalytic activity for the synthesis of vinyl chloride.

161, The preparation and catalytic properties of different bromine - free catalysts were discussed.

162, The results obtained show that pillared rare earth catalyst has higher catalytic activities and narrow molecular weight distribution, and does not corrode metal(), which makes it environmental friendly.

163, In the reaction of NAE 18 with nitrogen mustard aryl phosphorochloridate, 4 - dimethylaminopyridine ( DMAP ) played critical catalytic action.

164, By analyzing for the flange leakage on a heavy oil catalytic pyrolysis unit, the writer put forward a treatment method, i. e. to replace old asbestos gasket with a compound corrugated gasket.

165, Fluidized bed processing was first used commercially in fluid catalytic cracking of crude oil in 1941.

166, The invention discloses a catalytic purification method of chlorobenzene waste gas.

167, The results showed that the macrostructure, the composition of the crystal phase and the catalytic activity of the catalyst are related to the calcining temperature.

168, Another important aspect of enzymes activity addition to catalytic power is the specificity of enzymes reactions.

169, Compared the catalytic activity of ferric chloride hexahydrate, stannic chloride pentahydrate and sodium bisulfate monohydrate for synthesis of nerolin bromelia.

169, try its best to collect and make good sentences.

170, The dual-group hydrocarbon type rubber plasticizer was prepared using the heavy components in the production of heavy oil catalytic cracking by secondary deasphalting process.

171, Usually a pipe, known as a dip leg, is connected to this bottom outlet and, in catalytic cracking, serves to convey the solids back to the catalyst bed.

172, Binding of dioxygen and catalytic activity are the promising properties.

173, After acid catalytic dehydration the condensate subsequent hydrolysis was proceeded in the existence of protective agent, the yield of hydroxycitronellal came up to 87.7%.

174, The catalytic oxidation ability of 13 metal ion-exchanged montmorillonites are investigated in oxidative removal of the sulfides which are the main pollutant in the moult and alkali swell waste water.

175, Glyoxylic acid was rapidly synthesized by catalytic oxidation of glyoxal with H 2 O 2.

176, Nickel coating is deposited through redox reaction in the presence of catalytic centers.

177, The main treatment methods of spent electroless nickel plating solution include chemical deposition, catalytic reduction, electrolysis, ionic exchange, etc.

178, The component is the catalytic converter, which has a mandatory part of exhaust systems since 1975.

179, The effects of HZSM 5 zeolite ion exchanged by transition metals on catalytic pyrolysis reaction and the yields of ethylene and propylene using light gas oil feedstock were studied.

180, The mass fraction of n - butene in mixed C 4 from catalytic cracking after etherized was approximately 40 %.

181, The mechanism of hexa- coordinate phosphorus intermediate explains the catalytic effect of imidazole.

182, The catalytic converter can also be destroyed by excessive engine vibration.

183, In this paper, it is reported to use the method of phase transfer catalytic synthesis of 4"-O-Ethyldauricinc from Dauricine."

184, Isobornyl ethyl ether was prepared by the catalytic ethoxylation of camphene with ethyl alcohol in the presence of cation exchange resin fixed bed.

185, Objective:To probe into applying catalytic models to the positive rate of stool examination age distribution data of schistosomiasis.

186, The invention can ensure that the catalyst-to-oil ratio is flexibly improved during the catalytic cracking reaction.

187, Brown gas catalytic combustion technology can be widely used for various kind of waste incinerators.

188, This paper describes reuse technology of waste rubble based on catalytic cracking process.

189, The ideas for further development of the residuum catalytic cracking reaction technology according to the problems of commercial riser were discussed.

190, This paper reports our studies on the purification of wastewater containing unsym. dimethyl hydrazine (UDMH) by catalytic oxidation, using air or H2O2 as the oxidant.

191, The catalytic dehydration of lemonile with various alkalis and PTC was studied. The optimal conditions dehydration to lemonile for KOH TBAB catalytic by orthogonal design were determined.

192, Rare earth perovskite-type oxide catalyst as a substitute for traditional rare metal catalyst has a great potential to purify automotive emission due to good catalytic activity and low cost.

193, The computation fluid dynamics(CFD) is used to predict the flow filed inside the selective catalytic reduction(SCR)system of a 600MW power plant.

194, On account of co-metallomicelle formation, the complex with a long alkanol ligand has a stronger catalytic effect than that with a short alkanol ligand .

195, Catalytic synthesis of ketal by urushiol - formaldehyde neodymium polymer from cyclohexanone and ethanediol was studied.

196, It exhibited good catalytic activity for the hydrosilylation of olefins, such as decene, do-d...

197, In the catalytic systems for ethylene oligomerization, different organo-aluminum compounds significantly influence the activity and selectivity of the catalysts.

198, The removal efficiency of organics by catalytic ozonation technology for advanced treatment of micropolluted water was investigated by means of productive comparison test.

199, Its catalytic performance for Heck arylation of acrylic acid with iodobenzene shows that the catalyst has high catalytic activity and regioselectivity for the synthesis of trans-phenylacrylic acid.

200, Safety assessment of the combined device for catalytic cracking dead oil was made using DOS method.

201, The catalytic property of tne ball-type melted iron catalyst is also surveyed.

202, The catalytic performance of a deactivated commercial CB-8 Pt-Re reforming catalyst has been entirely recovered after chlorinating and retreating, which can be reused in the commercial unit.

203, In catalytic process physisorption and chemisorption may proceed at the same time.

204, This paper introduced the application of new type(BY)high efficient cyclone separation system in residual fluid catalytic cracking unit.

205, The GOR-DQ catalyst for reducing FCC gasoline olefinicity was designed on the basis of chemical reactions in catalytic cracking conditions.

206, The recent progress in catalytic hydrogenation of chloronitrobenzene to chloroaniline is reviewed.

207, Still, the results suggest that RNA has the raw catalytic power to catalyze its own replication.

208, Environmental catalytic material of iron nitride nanoparticle was synthesized by Benzene - thermal method.

209, Microwave (MW)-assisted wet catalytic oxidation (MAWCO) of pentachlorophenol (PCP) in the aqueous solution using activated carbon (AC) as catalytic was studied in this paper.

210, The curing agent has been prepared by one - step catalytic polymerization process with a specific chemical additive.

211, The results show that immobilized catalyst has higher catalytic activity. The catalyst can be used times. The yield of glyceryl triacetate is above 92%.

212, Catalytic oligomerization of remain butylene is a way for enterprises to rebottle andpotentialities for more benefits.

213, The researches of catalytic mechanism of S-adenosylhomocysteine (AdoHcy) hydrolase and acting mechanism of its inhibitors and the related product developing status in recent years were reviewed.

214, In the presence of catalytic amounts of samarium trichloride, acetophenone diethyl ketals reacted with acetyl chloride to give 1,3,5 - triarylbenzenes in high yields.

215, The catalytic decomposition method is a popular way of production carbon nanotubules.

216, The results have shown that the series of catalysts have higher acid catalytic activation, stability and selectivity to lower fatty ester.

217, The catalyst has high catalytic activity and excellent stability, both the conversion rate of TAME and the selectivity of isoamylene can be over 99%.

218, Meanwhile, because of the simple preparation, the high catalytic activity and the environmental protection, heteropoly compound is widely used in the area of catalysis.

219, Alkylation of ambident nucleophiles different places by using phase - transfer catalytic agent were studied in this paper.