971 resultados para Labour movement--Ontario--St. Catharines Region--History
Resumo:
This research work has been planned with the intention of proving the absolute configuration of lactobacillc acid. During the course of this work, attempts have been made to synthesize cis-2-carboxycyclopropane- l-.acetic acid as,v,a suitable resolvable material. As the results were not satisfactory, the synthesis of ci,s-2-carboxycyclopropane-l-propionic acid has been alternatively attempted by ring opening of bicyclo- [4.1.~-heptan-2-onewithout much success. Attempts to resolve or prepare bicyclo[ 4.1.~-hePtan-2-one optically active are also reported. On the other hand, a complete scheme is described for the possible synthesis of optically active lactobacillic acid. If only bicyclo- ~.1.~ -heptan-2-one can be resolved or prepared optically active, this described scheme can be applied smoothly to the synthesis of enant~omeric lactobacillic acid.
Resumo:
Calculations are performed on the \S <:Jd ground states of
d ' +
the H and HC) molecules using a basis set of non-integral
~ ~ I
elliptical orbitals. Different variational wavefunctions constructed
i- for H~ involved one parameter to three par~~eter variation.
In order to l"'educe the ntunber of parameters in most commonly
0-
used basis orbitals set, the importance of the term (,+~)
Y\ over the term ;u 'Where n is a variational pararneter and the value
of cr may be given by boundary condition or cusp condition is
outlined in Chapters II and III. It is found that the two parameter
-+
Resumo:
A great deal of data on the heats of formation of various hydrates has been compiled i n the J.A.N.A.F. and other tables such as the National Bureau of Standards circulars. Comparison of the heat of f ormation of a hydrate with that of the corresponding anhydrate exposes anomalies i n a surprising number of cases. Some of the results are so discordant that i t is apparent that one or the other value is seriously mistaken. No attempt has been made i n this work to determine which value may be correct, but measurements have been made of the difference between these two values. The procedure adopted has been to dissolve the hydrate and the anhydrate, to achieve the same final concentration of the compound in solution, and so to measure the difference in heats of solution .. Measurements were made at OOC in a modified Bunsen ice calorimeter, well insulated and surrounded by an icewater mixture . The observed differences in heats of solut ion were corrected t o 25°0 by using appropriate heat capacity data. These differences offer a direct measure of the enthalpy involved in binding a mole of water into the crystal structure and so should shed light on the nature of binding involved. The following hydrates were studied : MgS04.nH20 (n = 1,4,7), MnC12.nH20 (n = 1, 2), LiI. nH20 (n = 1,3), MnS04. nH20 (n = 1,4), CaC12. nH20 (n = 2,6) , K2C03.1~H20, LiCl.H20, LiBr.2H20, CdC12.2t H2o, and N2H4eH20.
Resumo:
The mass spectra of compounds of t he series (C6F5 )3-n MP~ (n = 1,2,3, M = P and As ), (C6F5>3Sb, Ph) Sb and (C6F5 )2SbPh have been studied in detail and the important modes of fragmentation were e1ucidated, a ided by metastable ions. Various trends attributed to the central atom and or the . substituent groups have been noted and, where applicable, compared to recent studies on related phenyl and pentafluorophenyl compounds of groups IV and V. The mass spectra of fluorine containing organometallic compounds exhibit characteristic migrations of fluorine to t he central atom, giving an increasing abundance of MF+, MF2+' and RMF+ (R = Ph or C6F5) ions on descending the group_ The mass spectra of pentafluorophenyl , antimony, and arsenic compounds show a greater fragmentation of the aromatic ring than those of phosphorus. The mixed phenyl pentafluorophenyl derivatives show a characteristic pattern depending on the number of phenyl grm.lps present but show t he general characteristics of both the tris(phenyl) and tris(pentafluorophenyl) compounds. The diphenyl pentafluorophenyl der ivatives show the loss of biphenyl ion as the most import ant step, the los s of phenyl t o give the i on PhMC6F5 + being of secondary importance. The ,bis(pentafluorophenyl) phenyl derivatives fragment primarily by loss of PhC6F5 to give C6F5M+ ions, the abundance of t hese increasing r apidly from phosphorus to arsenic. This species then, exhibits a characteristic fragmentation observed in the tris(penta- fluorophenyl ) compounds. However, the abundance of (C6F5)2M+ species in these compounds i s small. I ons of the type C6H4MC6F4 + and tetrafluorobiphenylene ions C6H4C6F4 + also are observed on substitution of a phenyl group for a penta- fluorophenyl group. The fully fluorinated species (C6F4)2M+ is not observed, although octafluorobiphenylene ions , (C6F4)2+' are evident in several spectra . The appearance potentials of the major ions were obtatned from the ionisation efficiency curves. Attempts were made to correlate these to the effect of the central atom in substituent groups, but the large errors involved prevented the reaching of quantitative conclusions, although it would appear that the electron is removed from the ligand in the ionisation of t he parent molecule .
Resumo:
The original objective of this work was to provide a simple generator w.hich would produce hydrogen torLfuel-cell feed and which could be operated under remote or northern conditions. A secondary objective was to maximize the yield of hydrogen and carbon monoxide from available feed-stocks. A search of the patent literature has indicated that the concept of a small Wulff-type generator is essentially sound and that hydrogen may be recovered from a wide variety of hydrocarbon feed-stocks. A simple experimental set-up has been devised, patterned after ~~t originally used by R. G. Wulff for producing acetylene. This provides a supply of feed-stock, with or Without a carrier gas, which may be passed directly through a heated tube, which may contain a catalyst. A suitable procedure has been devised for analysi~ effluent gases for hydrogen, oxygen, nitrogen, methane and carbon monoxide by gas chromatography with the column packed with .Molecular .:>ieve .5 4. Athanol with air a.s carrier gas and at the same time as oxidant o was thermolyzed at temperatures in the ra~e 700-1100 C, with or Wi~lout catalyst. Methanol with or without nitrogen as a carrier gas was also cracked with • the same type of reactor refractory tube, but the temperature range was lower t down to ,300 " C when a catalyst was used. The problems of converting methane to hydrogen and carbon monoxide effiCiently, using air and/or water as oxidants were also studied.
Resumo:
Nuclear magnetic resonance spectroscopy has been used to study donor-acceptor complexes of boron trifluoride with several ureas, tetramethylthiourea, tetramethylselenourea, and tetramethylquanidine as well as adducts of tetramethyl- -urea with BF2Cl, BFC1 2 , and BC1 3 - A large number of mixed tetrahaloborate ions, including some of the ternary ones such as BF2CIBr-,have been obtained by ligand exchange reactions and studied by NMR techniques. The bonding in these ions is of the same inherent interest as the bonding in the isoelectronic tetrahalomethanes which have been the subject of many detailed studies and have been involved in a controversy concerning the existence of and the nature of "fluorine hyperconjugation" or C-F P1T- Pn bonding_ Ligand exchange reactions also gave rise to the difluoroboron cation, (TMU)20BF2+o The difluoroboron cation has been observed in solutions of TMU-BF3 , and has been proposed as a possible intermediate for fluorine exchange reactions in BF3 adducts.
Resumo:
Exchange reactions between molecular complexes and excess acid
or base are well known and have been extensively surveyed in the
literature(l). Since the exchange mechanism will, in some way
involve the breaking of the labile donor-acceptor bond, it follows
that a discussion of the factors relating to bonding in molecular complexes
will be relevant.
In general, a strong Lewis base and a strong Lewis acid form a
stable adduct provided that certain stereochemical requirements are
met.
A strong Lewis base has the following characteristics (1),(2)
(i) high electron density at the donor site.
(ii) a non-bonded electron pair which has a low ionization potential
(iii) electron donating substituents at the donor atom site.
(iv) facile approach of the site of the Lewis base to the
acceptor site as dictated by the steric hindrance of the
substituents.
Examples of typical Lewis bases are ethers, nitriles, ketones,
alcohols, amines and phosphines.
For a strong Lewis acid, the following properties are important:(
i) low electron density at the acceptor site.
(ii) electron withdrawing substituents. (iii) substituents which do not interfere with the close
approach of the Lewis base.
(iv) availability of a vacant orbital capable of accepting
the lone electron pair of the donor atom.
Examples of Lewis acids are the group III and IV halides such
(M=B, AI, Ga, In) and MX4 - (M=Si, Ge, Sn, Pb).
The relative bond strengths of molecular complexes have been
investigated by:-
(i)
(ii)
(iii)
(iv)
(v]
(vi)
dipole moment measurements (3).
shifts of the carbonyl peaks in the IIIR. (4) ,(5), (6) ..
NMR chemical shift data (4),(7),(8),(9).
D.V. and visible spectrophotometric shifts (10),(11).
equilibrium constant data (12), (13).
heats of dissociation and heats of reactions (l~),
(16), (17), (18), (19).
Many experiments have bben carried out on boron trihalides in
order to determine their relative acid strengths. Using pyridine,
nitrobenzene, acetonitrile and trimethylamine as reference Lewis
bases, it was found that the acid strength varied in order:RBx3 >
BC1
3 >BF 3
• For the acetonitrile-boron trihalide and trimethylamine
boron trihalide complexes in nitrobenzene, an-NMR study (7) showed
that the shift to lower field was. greatest for the BB~3 adduct ~n~
smallest for the BF 3 which is in agreement with the acid strengths. If electronegativities of the substituents were the only
important effect, and since c~ Br ,one would expect
the electron density at the boron nucleus to vary as BF3
Resumo:
The purpose of this study was to determine novice t~ache~s' perceptions of th~ extent to which the Brock University teacher education program focused on strategies for promoting responsibility in students. Individual interviews were conducted with ten randomly selected teachers who were graduates of this teacher education program between the years of 1989 and 1992, and a follow-up group discussion activity, with the same teachers, was also held. Findings revealed that the topic of personal responsibility was discussed within various components of the program, including counselling group sessions, but that these discussions were often brief, indirect and inconsistent. Some of the strategies which the teachers used in their own classrooms to promote responsibility in students were ones which they had acquired from those counselling group °sessions or from associate teachers. Various strategies included: setting ~lear expectations of students with positive and negative consequences for behaviour (e.g., material rewards and detentions, respectively), cemmunic?ting'with other teachers an~ parents, and -. suspending students from school. A teacher's choice of any particular strategy seemed to be affected by his or her personality, teaching sUbject and region of employment, as well as certain aspects of the teacher education program. It was concluded that many of the teachers appeared to be controlling rude and vio~ent- behaviour, as opposed to promoting responsible behaviour. Recommendations were made for the pre-service program, as well as induction and inservice programs, to increase teacher preparedness for promoting responsible student behaviour. One of these recommendations addressed the need to help teachers learn how to effectively communicate with their students.
Resumo:
Low levels of ionizing radiation induce two translocation responses in soybean: a reduction in photoassimilate export from leaves and a change in the distribution pattern of exported photoassimilate within the plant. In this investigation these responses have been further studied specifically to ascertain the site of radiation damage and to better understand the physiological responses observed. Experimentally the primary data was obtained from studies in which a mature trifoliate leaf of a young soybean plant (Glycine ~ L. cultivar Harosoy '63) is isolated in a closed transparent chamber and allowed to photoassimilate 14C02 for 15 minutes. This is followed by an additional 45 ~_il'1;ute period before the plant is sectl.o ne d an d 14 C-ra dl' oactl.v.l ty d eterml. ne d'l n a 11 parts. Such 14c data provides one with the magnitude and distribution pattern of translocation. Further analyses were conducted to determine the relative levels of the major photosynthetic products using the techniques of paper chromatography and autoradiography. Since differences between control and irradiated P 1 ants were not 0 b serve d l' n t h e par tl't"lo nlng 0 f 14 C between the 80% ethanol-soluble and -insoluble fractions 14 or in the relative amounts of C-products of photosynthesis, the reduction in export in irradiated plants is not likely due to reduced availability of translocatable materials. Data presented in this thesis shows that photoassimilate export was not affected by gamma radiation until a threshold dose between 2.0 and 3.0 krads was reached. It was also observed that radiation-induced damage to the export process was capable of recovery in a period of 1 to 2 hours provided high light intensity was supplied. In contrast, the distribution pattern was shown to be extremely radiosensitive with a low threshold dose between .25 and .49 krads. Although this process was also capable of recovery,lt" occurred much earlier and was followed by a secondary effect which lasted at least for the duration of the experiments. The data presented in this thesis is interpreted to suggest that the sites of radiation action for the two translocation responses are different. In regards to photoassimilate export, the site of action of ionizing radiation is the leaf, quite possibly the process of photophosphorylation which may provide energy directly for phloem loading and for membrane integrity of the phloem tissue* In regards to the pattern of distribution of exported photoassimilate, the site is likely the apical sink, possibly the result of changes of levels of endogenous hormones. By the selection of radiation exposure dose and time post-irradiation, it is possible to affect independently these two processes suggesting that each may be regulated independent of the other and involves a distinct site.
Resumo:
This research was directed mainly towards the investigation of the reacti.ons of· substituted chlorobenziophenones under strongly basi,c conditions. The work 'can be divided into two main sections. The Introduction deals mainly with historical studies on aryne chemistry and the Haller-Bauer reaction. Secti.on I i.s concerned with syntheses of 2-benzamido-2'chlorobenzophenone and 2-benzamido~3'-chlorobenzophenone,and with thei,r respective reactions wi.th potassium amide in ammonia. o-Chlorophenylacetic acid was converted to the acid chloride and then by Friedel-Craftsreaction with benzene to w-(o-chlorophenyl)acetophenone. Reaction wi.th phenylhydrazine and Fischer cyclization gave 3- (0chlorophenyl)- 2-phenylindole, which was ozonized to 2-benzamido-2'chlorobenzophenone. The isomeric 3' -chlor,..o ke: tone was similarly synthesised from m-chlorophenylacetic acid. Both the 2'- and 3' -ch.loroketones gave N-benzoylacridone on treatment with potassium amide in ammonia; an aryne mechanism is involved for the 3'-chloroketone but aryne and nucleophilic substitution mechanisms are possible for the 2'-chloroketone. Hydrolysis of the 2'- and 3'-chloroketones gave 2-amino-2'chlorobenzophenone and 2-amino-3'-chlorobenzophenone respectively. A second new acridone synthesis is given in the Appendix involving reactions of these two ketones with potassium t-butoxide in t-butylbenzene. i Section 2 deals with the investigation of the reaction of some tricyclic ch1orobenzophenones with potassium amide in liquid ammonia. These were 1-ch1orof1uorenone; which was pr~pared in several steps from f1uoranthene, and 1- and 2-ch1oroanthraquinones. 1-Ch1orof1uorenone gave 1-aminof1uorenone ; 1-ch1oroanthraquinone gave 1- and 2-aminoanthraquinones; 2-ch1oroanthraquinone was largely recovered from the attempted reaction.
Resumo:
The one-electron reduced local energy function, t ~ , is introduced and has the property < tL)=(~>. It is suggested that the accuracy of SL reflects the local accuracy of an approximate wavefunction. We establish that <~~>~ <~2,> and present a bound formula, E~ , which is such that where Ew is Weinstein's lower bound formula to the ground state. The nature of the bound is not guaranteed but for sufficiently accurate wavefunctions it will yield a lower bound. ,-+ 1'S I I Applications to X LW Hz. and ne are presented.
Resumo:
1-(0- and m-Ohlorobenzoyl)isoquinolines have been synthesized by two routes involving Reissert compounds. One route involves condensation of 2-benzoyl-l,2-dihydroisoquinaldonitrile with the appropriate chlorobenzaldehyde and the second involves rearrangement of the appropriate Z-(chlorobenzoyl)-l,Z-dihydroisoquinaldonitrile under basic conditions. The action of potassamide in anhydrous liquid ammonia on both ketones gave unexpectedly N-(l-isoquinolyl)benzamide (67) as the major product and the use of dibenzo-18-crown-6-ether 98% substantially improved the yd..e.ld in the case of l-chloroketone. This amide (67) exhibits unusual hydrogen bonding. 1-(o-chlorobenzoyl)-6,7-dimethoxyisoquinoline (79) was prepared in very s,amll quantities by the route involving condensation of 2-benzoyll, Z-dihydro-6,7-dimethoxyisoquinaldonitrile with o-chlorobenzaldehyde. The poor yields are due to the instability of the anion of 2-benzoyl1, Z-dihydro-6,7-dimethoxyisoquinaldonitrile. Attempted preparation of the ketone (79) by rearrangement of 2-(o-chlorobenzoyl)-l,2-dihydro6,7- dimethoxyisoquinaldonitrile under basic conditions yielded the start~ng material (Reissert compound) and 6,7-dimethoxyisoquinoline. The action of potassamide in anhydrous liquid ammonia on l-(o-bromo-4,5-dimethoxybenzoyl)isoquinoline (85), which was prepared by the route involving the condensation of 2-benzoyl-l,4-dihydroisoquinaldonitrile with o-bromo-4,5-dimethoxybenzaldehyde, gave two products, which have not yet been identified. The ketone (85) and its precursors are interest~ng in that their 20 eV and 70 eV mass spectra do not show molecular ions.